Please note that the outfall series of reports continues until the present (November 2008) but not all the abstracts are listed here as the reports are essentially annual updates. While the abstracts of the newer studies are not provided here the reports are available from the WRRC, simply contact us with the year, outfall of interest, and type of report (benthic, fish and coral, fish histopathology, ROV inspection) and we will be happy to provide you with it.

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 2002

Brock, Richard E.

August 2002, 53 pp.

ABSTRACT

Benthic community structure and fish community structure are monitored quantitatively at sampling stations in the shallow marine environment near the Barbers Point Ocean Outfall for possible effects of treated sewage effluent inshore of the outfall diffuser discharge. The 2002 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

An analysis of the fish communities along the Barbers Point Ocean Outfall, 'Ewa Beach, O'ahu, Hawai'i, using remote video - 2002 data

Brock, Richard E.

July 2002, 22 pp.

ABSTRACT

A remotely controlled video camera is used to determine the status of fish and diurnally exposed macrobenthos resident to the diffuser at the Barbers Point Ocean Outfall. The 2002 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Necropsy and liver histopathology for fish sampled in the vicinity of the Barbers Point Ocean Outfall, O'ahu, Hawai'i, April 2002

Work, Thierry M.

June 2002, 10 pp.

ABSTRACT

Gross necropsy and fish liver histopathology are performed on 10 specimens each of three different fish species collected live near the terminus of the Barbers Point Ocean Outfall in April 2002. The fishes are examined for histologic changes, as part of an ongoing monitoring program.

Benthic faunal sampling adjacent to the Barbers Point Ocean Outfall, O'ahu, Hawai'i, January 2002

Swartz, Richard C., Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

May 2002, 193 pp.

ABSTRACT

Sediment samples are collected for biological and geochemical analyses to determine whether treated sewage effluent discharged through the Barbers Point Ocean Outfall has an effect on the benthic fauna in the surrounding area. The 2002 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, O'ahu, Hawai'i, 2001

Russo, Anthony R.

March 2002, 27 pp.

ABSTRACT

Benthic community structure and fish community structure are monitored quantitatively at sampling stations in the shallow marine environment near the Waianae Ocean Outfall for possible effects of treated sewage effluent inshore of the outfall diffuser discharge. The 2001 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Regional monitoring of benthic fauna in Mamala Bay, O'ahu, Hawai'i, August 2001

Swartz, Richard C., Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 2002, 158 pp.

ABSTRACT

Sediment samples are collected for biological and geochemical analyses to determine whether treated sewage effluent discharged through two ocean outfalls has an effect on the benthic fauna in Mamala Bay. The extent and magnitude of spatial changes in the structure of the benthic community in the bay are described.

Benthic sampling adjacent to the Waianae Ocean Outfall, O'ahu, Hawai'i, May 2001

Russo, Anthony R., E. Alison Kay, Julie H. Bailey - Brock, and William J. Cooke

December 2001, 172 pp.

ABSTRACT

Sediment samples are collected for biological and geochemical analyses to determine whether treated sewage effluent discharged through the Waianae Ocean Outfall has an effect on the benthic fauna in the surrounding area. The 2001 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Necropsy and liver histopathology for fish sampled in the vicinity of the Sand Island Ocean Outfall and in Maunalua Bay, O'ahu, Hawai'i, September 2001

Work, Thierry M.

December 2001, 17 pp.

ABSTRACT

Gross necropsy and fish liver histopathology are performed on 30 specimens each of two different fish species collected live near the terminus of the Sand Island Ocean Outfall and near reference stations in Maunalua Bay in September 2001. The Sand Island fishes are examined for histologic changes, as part of an ongoing monitoring program. The Maunalua Bay fishes provide a control for histopathologic changes that may be induced by a factor(s) unrelated to substances present in wastewater discharged from ocean outfalls in waters off O'ahu.

Necropsy and liver histopathology for fish sampled in the vicinity of the Waianae Ocean Outfall and at the reference station in Maunalua Bay, O'ahu, Hawai'i, 2001

Work, Thierry M.

November 2001, 16 pp.

ABSTRACT

Gross necropsy and fish liver histopathology are performed on 10 specimens each of three different fish species collected live near the terminus of the Waianae Ocean Outfall and another 10 specimens each of three different fish species collected live near the reference station in Maunalua Bay in September 2000. The Waianae fishes are examined for histologic changes, as part of an ongoing monitoring program. The Maunalua Bay fishes provide a control for histopathologic changes that may be induced by a factor(s) unrelated to substances present in wastewater discharged from ocean outfalls in waters off O'ahu.

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 2001

Brock, Richard E.

October 2001, 51 pp.

ABSTRACT

Benthic community structure and fish community structure are monitored quantitatively at sampling stations in the shallow marine environment near the Barbers Point Ocean Outfall for possible effects of treated sewage effluent inshore of the outfall diffuser discharge. The 2001 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Necropsy and liver kistopathology for fish sampled in the vicinity of the Barbers Point Ocean Outfall, O'ahu, Hawai'i, April 2001

Work, Thierry M.

September 2001, 12 pp.

ABSTRACT

Gross necropsy and fish liver histopathology are performed on 10 specimens each of three different fish species collected live near the terminus of the Barbers Point Ocean Outfall in April 2001. The fishes are examined for histologic changes, as part of an ongoing monitoring program.

An analysis of the fish communities along the Barbers Point Ocean Outfall, 'Ewa Beach, O'ahu, Hawai'i, using remote video - 2001 data

Brock, Richard E.

July 2001, 21 pp.

ABSTRACT

A remotely controlled video camera is used to determine the status of fish and diurnally exposed macrobenthos resident to the diffuser at the Barbers Point Ocean Outfall. The 2001 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Benthic faunal sampling adjacent to Barbers Point Ocean Outfall, O'ahu, Hawai'i, January 2001

Swartz, Richard C., Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 2001, 189 pp.

ABSTRACT

Sediment samples are collected for biological and geochemical analyses to determine whether treated sewage effluent discharged through the Barbers Point Ocean Outfall has an effect on the benthic fauna in the surrounding area. The 2001 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Benthic faunal sampling adjacent to Sand Island Ocean Outfall, O'ahu, Hawai'i, August 2000

Swartz, Richard C., Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 2001, 225 pp.

ABSTRACT

Sediment samples are collected for biological and geochemical analyses to determine whether treated sewage effluent discharged through the Sand Island Ocean Outfall has an effect on the benthic fauna in the surrounding area. The 2000 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 2000

Brock, Richard E.

January 2001, 50 pp.

ABSTRACT

Benthic community structure and fish community structure are monitored quantitatively at sampling stations in the shallow marine environment near the Barbers Point Ocean Outfall for possible effects of treated sewage effluent inshore of the outfall diffuser discharge. The 2000 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, O'ahu, Hawai'i, 2000

Russo, Anthony R.

January 2001, 27 pp.

ABSTRACT

Benthic community structure and fish community structure are monitored quantitatively at sampling stations in the shallow marine environment near the Waianae Ocean Outfall for possible effects of treated sewage effluent inshore of the outfall diffuser discharge. The 2000 data are compared with data from previous years to determine whether any statistically significant change has occurred in the measured biological parameters.

Necropsy and liver histopathology for fish sampled in the vicinity of the Sand Island Ocean Outfall and in Maunalua Bay, O'ahu, Hawai'i, September 2000

Brock, James A.

December 2000,19 pp.

ABSTRACT

Gross necropsy and fish liver histopathology are performed on 30 specimens each of two different fish species collected live near the terminus of the Sand Island Ocean Outfall and near reference stations in Maunalua Bay in September 2000. The Sand Island fishes are examined for histologic changes, as part of an ongoing monitoring program. The Maunalua Bay fishes provide a control for histopathologic changes that may be induced by a factor(s) unrelated to substances present in wastewater discharged from ocean outfalls in waters off O'ahu.

Benthic sampling adjacent to the Waianae Ocean Outfall, Oahu, Hawaii, June 2000

Russo, Anthony R.

October 2000

ABSTRACT not yet available

Necropsy and liver histopathology for fish sampled in the vicinity of the Waianae Ocean Outfall and at the reference station in Maunalua Bay, Oahu, Hawaii, 1999

Brock, James A.

August 2000

ABSTRACT not yet available

Benthic faunal sampling adjacent to the Barbers Point Ocean Outfall, Oahu, Hawaii, February-March 2000

Swartz, Richard C.

July 2000

ABSTRACT not yet available

Necropsy and liver histopathology for fish sampled in the vicinity of the Barbers Point Ocean Outfall, Oahu, Hawaii, February 2000

Brock, James A.

July 2000

ABSTRACT not yet available

Necropsy and liver histopathology for fish sampled in the vicinity of the Waianae Ocean Outfall and at the reference station in Maunalua Bay, Oahu, Hawaii, 1999

Brock, James A.

May 2000

ABSTRACT not yet available

Necropsy and liver histopathology for fish sampled in the vicinity of the Barbers Point Ocean Outfall, Oahu, Hawaii, February 1999

Brock, James A.

May 2000

ABSTRACT not yet available

Necropsy and liver histopathology for fish sampled in the vicinity of the Sand Island Ocean Outfall and in Maunalua Bay, Oahu, Hawaii, December 1999

Brock, James A.

March 2000

ABSTRACT not yet available

Benthic faunal sampling adjacent to the Sand Island Ocean Outfall, Oahu, Hawaii, September-October 1999

Swartz, Richard C.

March 2000

ABSTRACT not yet available

Benthic sampling adjacent to the Waianae Ocean Outfall, Oahu, Hawaii, May 1999

Russo, Anthony R.

January 2000

ABSTRACT not yet available

Hawaii rainwater catchment systems development: Suggested guidelines

Fok, Yu-Si

October 1999

ABSTRACT not yet available

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, Oahu, Hawaii, 1999

Russo, Anthony R.

October 1999

ABSTRACT not yet available

Project Report PR-2000-01

Benthic faunal sampling adjacent to Barbers Point Ocean Outfall, Oahu, Hawaii, April 1999

Swartz, Richard C., Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

August 1999

ABSTRACT

Benthic infauna in the vicinity of the Barbers Point Ocean Outfall was sampled at seven stations on 13 and 14 April 1999 with a modified van Veen grab sampler. The stations were located along the diffuser isobath (61 m) as follows: Station HZ within the zone of initial dilution (ZID); Stations HB2, HB3, and HB4 on the ZID boundary; Station HB6 at 0.5 km from the ZID; and Stations HB1 and HB7 at 3.5 km from the ZID. Sediments were predominantly (>90%) fine to coarse sands at all stations, although the proportion of medium and coarse sand was greater at Stations HB1, HB2, HB4, HZ, and HB7 than at Stations HB3, HB4, and HB6. Total organic carbon in the sediments at all stations was less than 0.02%. Values for oxidation-reduction potential and sediment oil and grease (O&G) showed no indication of significant organic buildup in sediments at any station except Station HB2. The high O&G values at Station HB2 were not associated with any biological alterations. A total of 9,679 nonmollusk individuals from 183 taxa were collected. Polychaetes represented 44.0%, nematodes 17.2%, crustaceans 14.2%, oligochaetes 9.9%, and sipunculans 9.5% of total nonmollusk abundance. Mean total nonmollusk abundance ranged from 152.6 individuals per sample (33,639/m², at Station HB1) to 355.8 individuals per sample (78,431/m², at Station HB6). Mean crustacean abundance ranged from 16.2 (3,571/m², at Station HB3) to 65.6 (14,461/m², at Station HB7). Mollusks were analyzed separately because they represent time-averaged collections of live and dead shells. Mean mollusk abundance ranged from 139.0/10 cm³ (at Station HB6) to 317.6/10 cm³ (at Station HZ). There were no significant differences among the seven stations in mean nonmollusk abundance, number of nonmollusk taxa, crustacean abundance, or number of crustacean taxa. There were significant differences in mollusk abundance and richness, but they do not indicate a spatial pattern related to the outfall. For example, reference station HB7 and ZID station HZ had more molluscan individuals and taxa than the other reference stations and the ZID-boundary stations. There has been a significant trend of increased abundance for nonmollusks within the entire study area since 1990. Since 1994, there has been a trend of increased abundance for mollusks. A temporal trend of decreased abundance for crustaceans that began in 1994, reversed itself in 1998 and 1999, when the density of crustaceans increased substantially over the 1997 level. Mean crustacean abundance averaged over the entire study period (1986 to 1999) was significantly lower at ZID-boundary station HB3 than at reference station HB6. However, for the 1999 collection the difference between these two stations was not significant. Both diversity and evenness values for both nonmollusks and mollusks were generally similar among all stations in 1999. Cluster analysis of nonmollusk data confirmed that all stations were relatively similar to one another in terms of species composition and relative abundance. There is no indication of any marked alteration of the benthic community composition related to station proximity to the diffuser.

Project Report PR-99-14

An analysis of the fish communities along the Barbers Point Ocean Outfall, Ewa Beach, Oahu, Hawaii, using remote video, 1999 data

Richard E. Brock

June 1999

ABSTRACT

Because the diffuser of the Barbers Point Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the marine fish communities and selected diurnally exposed macroinvertebrate species residing on the diffuser. Video reconnaissance was completed over the entire 534-m length. Three visual "transects," which "sampled" approximately 31% of the total diffuser length, were established on the diffuser pipe. Previous video samplings of the diffuser fish communities were carried out in January of 1992 through 1995 and 1998, in March of 1996, and in April of 1997 and 1999. The results of the eight annual surveys indicate that the diffuser fish communities are dominated by species that are either small as adults or juveniles of larger species, probably as a result of the presence of only small-scale shelter created by small armor rock and gravel used in constructing the discharge pipe. Because of poor camera resolution, differing angles of the camera, small fish sizes, and the fishesº nature to flee from the approaching camera, the fish census data are highly variable and should be viewed as more qualitative than quantitative in nature. Despite this variability from transect to transect and year to year, only one parameter showed any statistical change over the eight annual survey years. This parameter is the mean size of the area sampled to find an individual fish using the nonparametric Kruskal - Wallis analysis of variance. This statistical difference is related to the lower number of individual fish and macroinvertebrates encountered during the 1997 survey, which is related to the lowered ability to see fish due to poor visibility, camera resolution, and camera angle. Little significance should be attached to any change noted in the fish or macrobenthic communities residing on the Barbers Point diffuser because of the variable quality of the data generated by use of the remotely controlled video system.

Project Report PR-99-13

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 1999

Richard E. Brock

May 1999

ABSTRACT

This report provides the results of the eighth year of an annual quantitative monitoring of shallow marine communities inshore of the Barbers Point Ocean Outfall located in 61 m of water offshore of Ewa Beach, Oahu, Hawaii. The monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Field sampling was first carried out in August 1991 when three study stations were established: Station BP-1, a control station 2.2 km inshore and east of the outfall terminus; Station BP-2, an experimental station about 1.6 km inshore of the terminus; and Station BP-3, an experimental station about 2.9 km west and inshore of the terminus. The second field effort, completed in May and September 1993, resurveyed the above stations as well as established a fourth station (BP-4) on and adjacent to the basalt armor caprock protecting the discharge pipe in 13 m of water and directly inshore of the outfall terminus. Subsequent field surveys were completed in March and April 1994, in June 1995, in May 1996, in February and April 1997, in January and March 1998, and the most recent in January 1999. These permanently marked stations are sited to capitalize on presumed gradients of impact that may be created by the discharge and movement of treated sewage effluent toward the shore and the coral reef communities. Data from the first survey suggested that marine communities offshore of Ewa Beach receive disturbance from a number of possible sources, with the largest perturbation probably coming from natural disturbance caused by occasional wave impact. This was most evident at the station directly inshore of the outfall. Data from Station BP-4 showed that benthic communities situated on armor rock which rises above the flat limestone substratum are not subjected to the same sand scour as those situated on the limestone; thus the coral communities on the elevated caprock are better developed on this substrate. A comparison of the data from the eight annual surveys indicated that no statistically significant change has occurred in the measured biological parameters at these permanent stations, despite the imposition of a major hurricane on these marine communities in September 1992. Thus the data to date support the contention that the operation of the Barbers Point deep-ocean outfall is not having a quantifiable impact on the coral reef resources situated inshore of the outfall terminus.

Project Report PR-99-12

Necropsy and liver histopathology for fish sampled in the vicinity of the Sand Island Ocean Outfall, Oahu, Hawaii, October 1998

James A. Brock

March 1999

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1998 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Selar crumenophthalmus, Lutjanus kasmira, and Myripristis spp. These fish were collected live near the terminus of the Sand Island Ocean Outfall, Oahu, Hawaii. Two of the S. crumenophthalmus had a focus of early bile duct hyperplasia. Putative Myxosporidea spores were observed in the gall bladder of two other S. crumenophthalmus. Four of the L. kasmira had several putative Myxosporidea spores within bile ducts of the liver. Gross or microscopic evidence of neoplasia was not found in the liver of the 30 fish evaluated.

Project Report PR-99-11

Necropsy and liver histopathology for fish sampled at the control station in Maunalua Bay, Oahu, Hawaii, November 1998

James A. Brock

March 1999

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1998 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Myripristis spp., Lutjanus kasmira, and Selar crumenophthalmus. These fish were collected live at the control station in Maunalua Bay, Oahu, Hawaii. Gross or microscopic evidence of neoplasia was not found in the liver of the 30 fish evaluated.

Project Report PR-99-10

Benthic faunal sampling adjacent to Sand Island Ocean Outfall, Oahu, Hawaii, August 1998

Richard C. Swartz, Julie H. Bailey - Brock, William J. Cooke, E. Alison Kay

March 1999

ABSTRACT

Benthic fauna in the vicinity of the Sand Island Ocean Outfall was sampled at seven stations along the diffuser isobath in August 1998. Stations were located both within and on the boundary of the zone of initial dilution (ZID) and at distances of 1.2 to 2 km from the ZID boundary. Values for total organic carbon, total Kjeldahl nitrogen, and oxidation-reduction potential showed no indication of significant organic buildup in sediments at any station. Correlations between sediment oil and grease from Sand Island samples and both crustacean abundance and taxa richness showed no evidence of a negative relationship. There were no significant differences in mean nonmollusk abundance among the stations. The only significant difference in number of nonmollusk taxa was a reduction in richness at reference station B1. There were no significant differences among stations in mean crustacean abundance. ZID-boundary stations B3 and B4, within-ZID station Z, and reference station B1 had fewer crustacean taxa and noncopepod crustacean individuals than reference stations B2 and B6. There were no significant differences in the number of crustacean taxa and noncopepod crustaceans at reference station B1 and any of the four ZID-boundary and within-ZID stations. These comparisons indicate that the crustacean assemblage at the ZID and near-ZID stations was within the range of natural variability as defined by conditions at all three reference stations. There were significant differences among stations in mean mollusk abundance and number of mollusk taxa, but the differences showed no evidence of a negative effect of the diffuser effluent on mollusks. For example, mean mollusk abundance was significantly greater at reference station B2 and at ZID-boundary station B4 than at all other stations. Also, there were significantly more mollusk taxa at ZID station Z and ZID-boundary station B5 than at reference stations B1 and B6. Cluster analysis of nonmollusk species composition and abundance showed high similarity (>63%) among all stations. Reference and ZID stations were not segregated in the cluster pattern. There was no pattern of lower diversity or evenness for either nonmollusk or mollusk groups at ZID stations relative to reference stations. In fact, the highest diversity and evenness values for both mollusks and nonmollusks were observed at ZID-boundary station B5. The long-term pattern of lower species richness at Station B3, as compared to the other stations, was observed only for the crustacean component and not for other faunal components. The abundance and richness of amphipods and all crustaceans increased at all ZID and ZID-boundary stations in 1998. In summary, the response patterns of benthic fauna near the Sand Island Ocean Outfall showed little or no indication of a strong influence by the diffuser effluent.

Project Report PR-99-09

Community structure of fish and macrobenthos at selected sites in the vicinity of the Mokapu Ocean Outfall, Oahu, Hawaii, 1998

Richard E. Brock

January 1999

ABSTRACT

This report provides the results of the first quantitative survey of the coral reef communities in the vicinity of the Mokapu Ocean Outfall in Kailua Bay, Oahu, Hawaii. This survey, conducted in April and July 1998, focuses on benthic and fish community structure and is designed to detect community changes that may be mediated by the release of treated sewage through the outfall. The Kailua Regional Wastewater Treatment Plant (WWTP), which has been operational since 1977, releases a little more than 13 mgd of secondary treated sewage through a 1.55-km-long discharge pipe at a depth of 32 m. If impacts are occurring to marine communities from a point-source discharge, their effects will be most evident in proximity to the source and less obvious with distance from the source. The sampling strategy used in this study focuses on quantifying the degree of development of marine communities adjacent to and at distances from the discharge source. This strategy should allow delineation of impacts-if they are occurring. The results of this first survey indicate that the marine communities in the study area are diverse, with well-developed fish and coral components. This is particularly evident on the Mokapu Ocean Outfall diffuser (Transect T-1) where a high-biomass, diverse fish community occurs. This well-developed fish community is related to the shelter created by the diffuser pipe and basalt armor rock, as well as to the release of organic particles in the treated effluent which serve as a food resource for some fish species. The development of corals as measured in terms of live coverage in the diffuser pipe community is about half that found at the more distant sampling sites. However, a second sampling site (Transect T-2) located parallel to and 15 m away from the diffuser has coral coverage very similar to that found elsewhere in Kailua Bay. These data suggest that if the operation of the Kailua Regional WWTP is having an impact on marine communities, it is very limited in scope and scale.

Project Report PR-99-08

An analysis of the fish and macrobenthos along the Sand Island Ocean Outfall using remote video: IX.1998 data

Richard E. Brock

December 1998

ABSTRACT

Because the diffuser of the Sand Island Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the fish and diurnally exposed macrobenthos resident to the diffuser. The use of a remotely operated vehicle is stipulated in the National Pollutant Discharge Elimination System 301(h) waiver permit for the Sand Island Wastewater Treatment Plant. Video reconnaissance was completed over the entire 1,036 m length of the outfall diffuser. Five visual "transects," which "sampled" approximately 41% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser marine communities was carried out annually from 1990 through 1998. Only a few species of diurnally exposed macroinvertebrates are evident on the videotapes of the diffuser; the numbers are insufficient for any meaningful analysis. In 1998, 30 fish species (1,046 individuals) having an estimated biomass ranging from 13 to 220 g/m² (mean 59 g/m²) were censused. In the years from 1991 through 1997, the number of fish species encountered during a survey ranged from 22 species (in 1993) to 31 species (in 1992); the total number of individuals from 279 (in 1993) to 2,936 (in 1992); and the mean biomass from 21 g/m² (in 1993) to 92 g/m² (in 1996). Because the 1990 video census covered only the terminal 183 m of the diffuser, whereas the later surveys were spread out along the entire diffuser length, a direct comparison cannot be made between the 1990 data and the data for subsequent years. The 1998 census noted one "new" fish species for every 28.3 m² of substratum sampled and one fish for every 0.8 m². In the 1991 through 1997 period, measures of the fish community (number of species, number of individuals, and biomass)-after an initial increase from 1991 to 1992 and a decrease in 1993-have oscillated annually. From a statistical perspective, changes in the mean number of species per transect and the mean number of individual fishes per transect are significant (Kruskal - Wallis ANOVA); changes in the biomass of fishes over the same period are not significant. These changes in the fish community are attributed to changes in the general viewplane of the videotapes recorded in 1994 and later years from that recorded in earlier years, as well as to a change in the resolution of the videotape from which the data are derived. Poorer camera resolution results in lower counts; camera resolution is affected by local wind and currents interacting with the camera, tether, and support vessel as well as by water visibility. Controlling these sources of variation inherent with the use of the remotely operated video system is difficult if not impossible. Until an alternative can be found, the remotely controlled video system is the only low-cost means available to view the marine communities on the diffuser. Until a more accurate means of visual assessment is available, the biological data generated by the remotely operated video camera should be viewed as qualitative, with little statistical rigor.

Project Report PR-99-07

Community structure of fish and macrobenthos at selected sites fronting Sand Island, Oahu, Hawaii, in relation to the Sand Island Ocean Outfall, Year 9, 1998

Richard E. Brock

December 1998

ABSTRACT

This report provides the results of the ninth year of an annual quantitative monitoring (carried out in August and September 1998) of shallow marine communities inshore of the Sand Island Ocean Outfall, Oahu, Hawaii. This monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Marine communities offshore of Honolulu have received considerable perturbation over the last 100 years. Dumping of raw sewage in shallow water, which occurred from 1955 to 1977, was halted in 1978; however, point and nonpoint sources of pollution from both urban activities and industry continue. All of these disturbances may serve to obscure any impacts that may be caused by treated effluent discharged from the deep-ocean outfall. The marine communities show a considerable range in development that is probably related to historical impacts. Stations have been located to take advantage of these gradients. Analysis of the nine years of data showed that there has been no statistically significant change in any of the biological parameters measured in this study other than for the mean number of invertebrate species and numbers of individual invertebrates encountered per transect. In these cases the data for 1998 showed significantly greater numbers of species and individuals over other years. These changes are probably the result of higher than usual counts of the Christmas tree worm Spirobranchus giganteus corniculatus as well as just more invertebrate species present at most stations. All other measures of the communities in this study (i.e., percent coral cover, number of coral species, number of fish species, total number of fishes counted, and the biomass of fishes present at each station) showed no significant changes through the period of this study. Hurricane Iniki, which occurred in September 1992, impacted marine communities along the south shore of Oahu. Coral communities received considerable damage, especially at the westernmost study station. Recovery in these communities is evident from the six years of data collected since the storm. Thus far, this study has not detected a quantifiable negative impact from the operation of the Sand Island Ocean Outfall.

Project Report PR-99-06

Benthic sampling adjacent to the Waianae Ocean Outfall, Oahu, Hawaii, May 1998

Anthony R. Russo, E. Alison Kay, Julie H. Bailey - Brock, and William J. Cooke

November 1998

ABSTRACT

In May 1998, bottom samples were collected by scuba divers near the Waianae Ocean Outfall at a depth of approximately 33 m. The Waianae outfall is located on the leeward side of the island of Oahu, Hawaii. The six stations sampled were (1) Station Z, located in the zone of initial dilution (ZID) at the diffuser; (2) Station ZE, located on the southeast boundary of the ZID, about 30 m from the diffuser; (3) Station ZW, located about 60 m southwest of the diffuser; (4) Station W1, located about 2.5 km southeast of the diffuser; (5) Station W2, located about 1.0 km southeast of the diffuser; and (6) Station W9, located about 2.5 km northwest of the diffuser. The bottom at all stations was comprised of more than 90% fine to coarse sand. Station W2 had the coarsest sediments with a relatively high percentage of coral rubble. Oxidation-reduction potential and total volatile solid measurements indicated a nonreducing benthic environment at all stations. A total of 5,229 nonmollusk individuals representing 158 taxa and 9,512 mollusk individuals representing 181 taxa were recorded. The sediments around the outfall were rich in nematode, oligochaete, polychaete, crustacean, and molluscan fauna. Polychaetes represented 35.2% and crustaceans 15.1% of total nonmollusk abundance. Polychaetes were represented by 90 taxa and crustaceans by 45 taxa. Gastropods comprised more than 90% of the molluscan fauna. The highest mean abundance of nonmollusks was recorded at reference station W9 and the lowest at reference station W1. Mean nonmollusk taxa richness was greatest at Station W2 and least at Station W1. Highest mean mollusk abundance was recorded at reference station W1 and lowest at Station W2. Mean taxa richness for the mollusk component was highest at Stations W9 and W1 (same amount for both) and lowest at Station W2. The nonmollusk taxa composition was similar at Stations ZE and Z. These stations, taken as a group, were most dissimilar to the remaining group of stations comprised of Stations W9, W1, W2, ZW, and Z. For mollusks, Stations Z and W1 were most similar, whereas Station ZE was most dissimilar to the other stations in taxa composition. In 1998 there was a decrease in mean nonmollusk taxa at all stations except ZW and W2. From 1989 to 1993 the ZID and non-ZID station groups showed parallel shifts in nonmollusk taxa richness, whereas in 1994 non-ZID station group values increased and ZID station group values decreased, such that the values for the two groups converged. The values for both groups remained close in 1995, 1996, 1997, and 1998. Mean nonmollusk abundance shifted similarly for ZID and non-ZID station groups among the years of survey, except in 1993 when there was a decrease for the non-ZID station group relative to the ZID station group. In 1995, 1996, 1997, and 1998 nonmollusk abundance values for the two groups remained close. Annual averages for total suspended solids, total phosphorous, and total nitrogen concentrations in the outfall effluent were essentially the same in 1997 and 1998. At all stations the sediment was oxygen-rich, as indicated by positive oxidation-reduction potential readings. Mean taxa richness between ZID (27 taxa) and non-ZID (31 taxa) station groups was not significantly different. Cluster analysis indicated there was no pattern or grouping of stations, according to taxa composition, which showed an interaction with the sewage discharge. Near the outfall discharge, no large increase in abundance was found among some taxa relative to others; the equitability of relative abundances was high at all stations. There was no large decrease in taxa diversity at stations near the diffuser, as predicted by the Pearson - Rosenberg pollution model. Thus all of the results of the 1998 Waianae benthic study, along with results from previous years, suggest that no deleterious effects occur on the biologically indigenous populations near the outfall from sewage discharge.

Project Report PR-99-05

Subsurface geology and hydrogeology of downtown Honolulu, with engineering and environmental implications

Sue A. Finstick

October 1998

ABSTRACT

In the downtown Honolulu area, detailed site investigations are required prior to the design and construction of high-rise buildings and other engineering structures. Hence, over the years, numerous soil borings, environmental assessments, and groundwater measurements have been conducted. As a result, much data on the subsurface geology of downtown Honolulu exists, but it is spread out among individual consulting firms and various governmental agencies. The purpose of this study is to compile the existing data and interpret the subsurface geology, engineering geology, hydrogeology, and environmental problems within the downtown Honolulu area. This study commenced with collecting and interpreting data from 2,276 soil boring logs from consulting firms in Honolulu, along with data from the Groundwater Index database and environmental databases maintained by the State of Hawaii. The subsurface materials are classified into nine categories: fill, lagoonal (low-energy) deposits, alluvial deposits, coralline debris, coral ledges, cinders, tuff, basalt, and residual soil or weathered volcanics. The study area is divided into 157 quadrangles (1,000 feet Ä 1,000 feet each). The subsurface conditions within each quad are described in detail, and nine cross-sections are presented for further clarification of the subsurface geology. Foundation-bearing layers and buried alluvial channels are mapped. Environmental problems and groundwater data are summarized in tables and maps. Coral ledges, tuff, and basalt are the most suitable foundation-bearing layers within the caprock. Coral ledges, coralline debris, coarse-grained lagoonal sediments, and cinder sands are characterized by higher hydraulic conductivities than other materials that comprise the caprock. However, the caprock as a whole is characterized by much lower hydraulic conductivities than the underlying Koolau basalt that forms the main aquifer for the island. The caprock groundwater is not only brackish and nonpotable but also highly vulnerable to contamination. Petroleum hydrocarbons and heavy metals from leaking underground storage tanks are the primary soil and groundwater contaminants. Caprock groundwater is generally found within ±5 feet of sea level. Dewatering is often necessary at sites involving the construction of basements.

Project Report PR-99-04

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, Oahu, Hawaii, 1998

Anthony R. Russo

September 1998

ABSTRACT

In 1998, coral growth and fish abundance were monitored at stations located at and in the vicinity of the Waianae Ocean Outfall. Comparisons of results with fish surveys done in previous years showed no significant differences in the species composition or relative abundances of fish populations at Station W-2 (the sunken ship Mahi), which is located 1.2 km south of the diffuser. Fish abundance and species richness at Station W-3, which is located at the diffuser, increased from 1990 to 1995, decreased in 1996, and increased again in 1997 and 1998. At Station WW, an inshore station located 0.8 km from shore, fish were abundant and speciose on the armor rock covering the pipeline. The fish species seen inshore are comparable to fish species seen in similar (boulder) natural biotopes around Hawaii. There were no significant differences in total mean coral cover at selected quadrats from 1994 to 1998 at Station W-2. However, when comparing 1991 data with 1998 data, there was a significant increase (4.6%) in total mean coral cover at this station. At the diffuser, corals were seen growing on the diffuser pipe and on the riser discharge ports. In 1986, when the diffuser began operation at a discharge rate of 1.5 mgd (0.07 m³/s), no corals were seen at this location. At inshore station WW corals off the pipeline were sparsely distributed but were numerous and thriving on the armor rock over the pipeline. The inshore transect (Alpha), off the armor rock, was moderately covered (less than 30%) with the alga Dictyopteris plagiogramma. This seaweed was also abundant at this location in 1995, 1996, and 1997. The water was clear at all stations surveyed (15 to 20 m horizontal visibility), and the surrounding sediments were clean and white. No significant deleterious effect due to outfall operation and discharge were seen on the biological community at the stations surveyed. The increase in fish diversity and abundance at the diffuser in 1998 may be due to natural fluctuations in abundance or to environmental conditions suitable to fish populations living there. To distinguish between outfall effects and natural fish population fluctuation patterns, several years of consecutive monitoring must be performed.

Project Report PR-99-03

Necropsy and liver histopathology for fish sampled in the vicinity of the Waianae Ocean Outfall, Hawaii, June 1998

James A. Brock

August 1998

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1998 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Myripristis spp., Lutjanus kasmira, and Selar crumenophthalmus. These fish were collected live near the terminus of the Waianae Ocean Outfall. Gross or microscopic evidence of neoplasia was not found in the livers of the 30 fish evaluated.

Project Report PR-99-02

Benthic sampling in the vicinity of the Mokapu Ocean Outfall, Oahu, Hawaii, March 1998

Anthony R. Russo, E. Alison Kay, Julie H. Bailey - Brock, William J. Cooke

August 1998

ABSTRACT

In March 1998, City and County of Honolulu scuba divers collected bottom sediment samples for biological and geochemical analyses in the vicinity of the Mokapu Ocean Outfall on the windward coast of Oahu, Hawaii. Six stations along the 34-m diffuser isobath were sampled: Station B1 at 33 m north and Station B2 at 33 m south of the diffuser on the boundary of the zone of initial dilution (ZID), Station Z in the ZID, Station A at 1 km north and Station C at 1 km south of the diffuser, and Station D at 3.2 km south of the diffuser. The net current direction is to the north in this area. All stations had sediment fractions with greater than 90% sand. Sediment grain size was essentially the same at all stations. Oxidation-reduction potentials were positive and did not show major fluctuations among stations. Total organic carbon in the sediment was less than 1% (dry weight) at all stations. All sediments were clean, devoid of particulates, and considered non-reducing. A total of 7,576 nonmollusks (216 taxa) and 7,320 mollusks (206 taxa) were collected. The sediments were rich and diverse with polychaetes, crustaceans, nematodes, oligochaetes, and gastropod mollusks. The pattern of abundance among stations for nonmollusks, mollusks, and crustaceans was parallel except at Station D. Shifts in taxa richness for all three components of the benthos were similar among stations. Comparisons among 1986, 1992, and 1998 studies at the same stations showed a large decrease in nonmollusk abundances (especially for the crustacean component) from 1986 to 1992, followed by an increase in 1998 at Stations A, B1, B2, and D. Nonmollusk taxa richness decreased between 1986 and 1992, but the decrease was only significant at Station A, the northernmost station that is most affected by wave scour. Nonmollusk taxa richness increased from 1992 to 1998. Differences in sampling seasons between 1986 (post-summer) and 1992 (post-winter) may be the reason for differences seen in benthic community distribution and abundance for those years, reflecting disturbances in the sedimentary environment because of severe winter storms from November 1991 to February 1992. Mollusks generally increased in abundance and diversity among all years of study. Crustacean abundances were lower in 1992 than in 1986 but higher in 1998 than in 1992 at Stations A, Z, B2, and C. Increases in crustacean diversity in 1998 over those in 1992 were recorded at stations A, B2, C, and D. Faunal species diversity appears to be a better measure of changes in the benthic community than abundance patterns since benthic fauna reproduce rapidly, resulting in wide swings in abundance from season to season and from year to year. Whatever the effect, if any, of the Mokapu outfall discharge on the benthic community in the area, fluctuations in community abundance and lesser variations in the community diversity were seen at all stations, including those 1 km or farther from the ZID. There was no pattern or grouping of stations for nonmollusk or mollusk taxa composition which indicated an outfall effect on the benthos. ZID stations, taken as a group, did not differ significantly from non-ZID stations in mean abundance or mean taxa richness. Benthic communities near the Mokapu outfall may be structured more by seasonal sedimentary disturbances than by the outfall discharge.

Project Report PR-99-01

Necropsy and liver histopathology for fish sampled in the vicinity of Barbers Point Ocean Outfall, Oahu, Hawaii, Febuary 1998

James A. Brock

July 1998

ABSTRACT

Fish liver histopathology is an important biological impact that is monitored near the terminus of the Barbers Point Ocean Outfall. In 1998 gross necropsy and fish liver histopathology were conducted on 10 live specimens each of three different fish species: Selar crumenophthalmus, Lutjanus kasmira, and Myripristis spp. Gross evidence of neoplasia was not found in the integument or in the liver of the 30 fish evaluated. Hyperplasia and periductal fibrosis were found in the liver of one S. crumenophthalmus (specimen 98-30A8) and eight L. kasmira (specimens 98-30B1, 98-30B2, 98-30B4, 98-30B5, 98-30B6, 98-30B8, 98-30B9, and 98-30B10). A putative Myxosporea parasite was observed in the gall bladder of nine of the fish. The cause is undetermined for the proliferative response in the biliary system observed in some of the fish.

Project Report PR-98-14

An analysis of the fish communities along the Barbers Point Ocean Outfall, Ewa Beach, Oahu, Hawaii, using remote video, 1998 data

Richard E. Brock

June 1998

ABSTRACT

Because the diffuser of the Barbers Point Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the marine fish communities and selected diurnally exposed macroinvertebrate species residing on the diffuser. Video reconnaissance was completed over the entire 534-m length. Three visual "transects," which "sampled" approximately 31% of the total diffuser length, were established on the diffuser pipe. Previous video samplings of the diffuser fish communities were carried out in January of 1992 through 1995, in March of 1996, and in April of 1997. This year the video sampling was carried out in January. The results of the seven annual surveys indicate that the diffuser fish communities are dominated by species that are either small as adults or juveniles of larger species, probably as a result of the presence of only small-scale shelter created by small armor rock and gravel used in constructing the discharge pipe. Because of poor camera resolution, differing angles of the camera, small fish sizes, and the fishesº nature to flee from the approaching camera, the fish census data are highly variable and should be viewed as more qualitative than quantitative in nature. Despite this variability from transect to transect and year to year, only one parameter showed any statistical change over the seven annual survey years. This parameter was the mean size of the area sampled to find an individual fish using the nonparametric Kruskal - Wallis analysis of variance. This statistical difference is related to the lower number of individual fish and macroinvertebrates encountered during the 1997 survey, which is related to the lowered ability to see fish due to poor visibility, camera resolution, and camera angle. Little significance should be attached to any change noted in the fish or macrobenthic communities residing on the Barbers Point diffuser because of the variable quality of the data generated by use of the remotely controlled video system.

Project Report PR-98-13

Benthic faunal sampling adjacent to Barbers Point Ocean Outfall, Oahu, Hawaii, January 1998

Richard C. Swartz, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

June 1998

ABSTRACT

Benthic infauna in the vicinity of the Barbers Point Ocean Outfall was sampled at seven stations on 10 and 12 January 1998 with a modified van Veen grab sampler. The stations were located along the diffuser isobath (61 m) as follows: Station HZ within the zone of initial dilution (ZID); Stations HB2, HB3, and HB4 on the ZID boundary; Station HB6 at 0.5 km from the ZID; and Stations HB1 and HB7 at 3.5 km from the ZID. Sediments were predominantly (>90%) fine to coarse sands. Stations HB1 and HB7 had relatively coarser sediments than other stations, and Station HB2 had relatively finer sediments. Total organic carbon in the sediments at all stations was near or below the detection limit of the analytical method used. Values for oxidation-reduction potential and sediment oil and grease showed no indication of significant organic buildup in sediments at any station. A total of 8,373 nonmollusk individuals from 140 taxa were collected. Polychaetes represented 42.1%, nematodes 24.6%, oligochaetes 11.5%, sipunculans 9.8%, and crustaceans 8.3% of total nonmollusk abundance. Mean total nonmollusk abundance ranged from 140.4 individuals per sample (30,949/m²) at Station HB2 to 392.2 individuals per sample (86,455/m²) at Station HB6. Mean crustacean abundances ranged from 4.0 (882/m²) at Station HB3 to 32.2 (7,098/m²) at Station HB6. Mollusks were analyzed separately because they represent time-averaged collections of live and dead shells. Mean mollusk densities ranged from 229.0 at Station HB7 to 414.0 at Station HB1. From comparisons of nonmollusk abundance among stations, reference station HB6 had significantly greater mean abundances than reference stations HB1 and HB7 and ZID-boundary stations HB2 and HB3. There has been a significant trend of increased abundance for nonmollusks within the entire study area since 1990. Since 1994, there has been a trend of increased abundance for mollusks. A temporal trend of decreased abundance for crustaceans began in 1994, but reversed itself in 1998 when the density of crustaceans increased substantially over the 1997 level. In 1998 the mean number of nonmollusk taxa at Station HB3 was significantly less than at Stations HZ and HB6, and the mean number of nonmollusk taxa at Station HB2 was significantly less than at Station HZ. The mean number of crustacean taxa was significantly less at Station HB3 than at Stations HB1, HZ, HB6, and HB7. Station HB2 had significantly fewer mollusk taxa than all other stations, and Station HZ had significantly fewer mollusk taxa than Station HB1. Mean crustacean abundance and taxa richness averaged over the entire study period and in 1998 were lower at two stations near the diffuser relative to reference stations. Although most station differences in crustaceans were not significant, the pattern may indicate a trend related to proximity to the diffuser. However, this trend is not consistent for all crustacean parameters, e.g., the total number of crustacean taxa collected at ZID station HZ was greater than at two of the reference stations in 1998. Both diversity and evenness values were generally similar among all stations in 1998 for both nonmollusks and mollusks. Cluster analysis of nonmollusk data confirmed that all stations were relatively similar to one another in terms of species composition and relative abundance. There is no indication of any marked alteration of the benthic community composition related to station proximity to the diffuser.

Project Report PR-98-12

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 1998

Richard E. Brock

May 1998

ABSTRACT

This report provides the results of the seventh year of an annual quantitative monitoring of shallow marine communities inshore of the Barbers Point Ocean Outfall located in 61 m of water offshore of Ewa Beach, Oahu, Hawaii. The monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Field sampling was first carried out in August 1991 when three study stations were established: Station BP-1, a control station 2.2 km inshore and east of the outfall terminus; Station BP-2, an experimental station about 1.5 km inshore of the terminus; and Station BP-3, an experimental station about 2.9 km west and inshore of the terminus. The second field effort, completed in May and September 1993, resurveyed the above stations as well as established a fourth station (BP-4) on and adjacent to the basalt armor caprock protecting the discharge pipe in 13 m of water and directly inshore of the outfall terminus. The third field survey was completed in March and April 1994, the fourth in June 1995, the fifth in May 1996, the sixth in February and April 1997, and the seventh in January - March 1998; each sampled all four stations. These stations are sited to capitalize on presumed gradients of impact that may be created by the discharge and movement of treated sewage effluent toward the shore and the coral reef communities. Data from the first survey suggested that marine communities offshore of Ewa Beach receive disturbance from a number of possible sources, with the largest perturbation probably coming from natural disturbance caused by occasional wave impact. This was most evident at the station directly inshore of the outfall. Data from Station BP-4 showed that benthic communities situated on armor rock which rises above the flat limestone substratum are not subjected to the same sand scour as those situated on the limestone; thus the coral communities on the elevated caprock are better developed on this substrate.A comparison of the data from the seven annual surveys indicated that no statistically significant change has occurred in the measured biological parameters at these permanent stations, despite the imposition of a major hurricane on these marine communities in September 1992. Thus the data to date support the contention that the operation of the Barbers Point deep-ocean outfall is not having a quantifiable impact on the coral reef resources situated inshore of the outfall terminus.

Project Report PR-98-11

Benthic sampling adjacent to the Waianae Ocean Outfall, Oahu, Hawaii, July 1997

Anthony R. Russo, E. Alison Kay, Julie H. Bailey - Brock, and William J. Cooke

April 1998

ABSTRACT

In July 1997, bottom samples were collected by scuba divers near the Waianae Ocean Outfall at a depth of approximately 33 m. The Waianae outfall is located on the leeward side of the island of Oahu, Hawaii. The six stations sampled were (1) Station Z, located in the zone of initial dilution (ZID) at the diffuser; (2) Station ZE, located on the southeast boundary of the ZID, about 30 m from the diffuser; (3) Station ZW, located about 60 m southwest of the diffuser; (4) Station W1, located about 2.5 km southeast of the diffuser; (5) Station W2, located about 1.0 km southeast of the diffuser; and (6) Station W9, located about 2.5 km northwest of the diffuser. The bottom at all stations was comprised of more than 90% fine to coarse sand. Station W2 had the coarsest sediments with a relatively high percentage of coral rubble. Oxidation-reduction potential and total volatile solid measurements indicated a nonreducing benthic environment at all stations. A total of 6,883 nonmollusk individuals representing 182 taxa and 12,964 mollusk individuals representing 206 species were recorded. The sediments around the outfall were rich in nematode, oligochaete, polychaete, crustacean, and molluscan fauna. Polychaetes represented 34.4% and crustaceans 20.9% of total nonmollusk abundance. Polychaetes were represented by 101 species and crustaceans by 61. Gastropods comprised more than 90% of total molluscan fauna. The highest mean abundance of nonmollusks was recorded at ZID station Z and the lowest at ZID station ZW. Mean nonmollusk taxa richness was greatest at Station W2 and least at Station ZW. Highest mean mollusk abundance was recorded at reference station W1 and lowest at Station W2. Mean species richness for the mollusk component was highest at Station W9 and lowest at Station ZW. The nonmollusk taxa composition was similar at all Stations ZE and ZW. These stations, taken as a group, were most dissimilar to the group of stations comprised of Stations W9, W1, W2, and Z. For mollusks, Stations Z and ZW were most similar. Stations ZE and W2 were also quite similar in taxa composition as were Stations W9 and W1. These three pairs of stations were all dissimilar to each other in mollusk taxa diversity. In 1997 there was an increase in nonmollusk taxa (excluding crustaceans) at Stations W1, W2, Z, and W9. From 1989 to 1993 the ZID and non-ZID station groups showed parallel shifts in nonmollusk taxa richness, whereas in 1994 non-ZID station group values increased and ZID station group values decreased, such that the values for the two groups converged. The values for both groups remained essentially the same in 1995, 1996, and 1997. Mean nonmollusk abundance shifted similarly for ZID and non-ZID station groups among the years of survey, except in 1993 when there was a decrease for the non-ZID station group relative to the ZID station group. In 1995, 1996, and 1997 nonmollusk abundance values for the two groups converged. Annual averages for total suspended solids, total phosphorous, and total nitrogen concentrations in the outfall effluent were slightly higher in 1997 than in 1996, whereas the annual average for biochemical oxygen demand was lower. At all stations the sediment was oxygen-rich, as indicated by positive oxidation-reduction potential readings. Mean species richness between ZID and non-ZID station groups was not statistically different. Cluster analysis indicated there was no pattern or grouping of stations, according to species composition, which showed an interaction with the sewage discharge. Near the outfall discharge, no large increase in abundance was found among some species relative to others; the equitability of relative abundances was high at all stations. There was no large decrease in species diversity at stations near the diffuser, as predicted by the Pearson - Rosenberg pollution model. Thus all of the results of the 1997 Waianae benthic study, along with results from previous years, suggest that no deleterious effects occur on the biologically indigenous populations near the outfall from sewage discharge.

Project Report PR-98-10

Necropsy and liver histopathology for fish sampled in the vicinity of the Sand Island Ocean Outfall, Oahu, Hawaii, September 1997

James A. Brock

March 1998

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1997 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Myripristis spp., Lutjanus kasmira, and Selar crumenophthalmus. All specimens were collected live in the immediate vicinity of the Sand Island Ocean Outfall, Oahu, Hawaii. Gross or microscopic evidence of neoplasia was not found in the livers of the 30 fish evaluated.

Project Report PR-98-09

Necropsy and liver histopathology for fish sampled at the control station in Maunalua Bay, Oahu, Hawaii, October-November 1997

James A. Brock

March 1998

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1997 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Selar crumenophthalmus, Lutjanus kasmira, and Myripristis spp. collected live at the control station in Maunalua Bay, Oahu, Hawaii. Gross or microscopic evidence of neoplasia was not found in the liver of the 30 fish evaluated.

Project Report PR-98-08

Benthic faunal sampling adjacent to Sand Island Ocean Outfall, Oahu, Hawaii, August 1997

Richard C. Swartz, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 1998

ABSTRACT

Benthic fauna in the vicinity of the Sand Island Ocean Outfall was sampled at seven stations along the diffuser isobath in August 1997. Stations were located both within and on the boundary of the zone of initial dilution (ZID) and at distances of 1.2 to 2 km from the ZID boundary. Values for total organic carbon, total Kjeldahl nitrogen, and oxidation-reduction potential showed no indication of significant organic buildup in sediments at any station. Correlations between sediment oil and grease from Sand Island samples and both crustacean abundance and species richness showed no evidence of a negative relationship. There were no significant differences in mean nonmollusk abundance or number of nonmollusk taxa among the stations. There were no significant differences among stations in mean crustacean abundance, although the mean number of noncopepod crustaceans was significantly less at within-ZID station Z and ZID-boundary station B3 than at reference station B6. There were significantly more crustacean taxa at all three reference stations (B1, B2, and B6) than at Station B3 and significantly more crustacean taxa at Station B6 than at Station Z. No other pairwise differences in stations for the nonmollusk or crustacean component of the benthic fauna were significant. Therefore, there was no general relationship between nearness to the diffuser and the abundance and richness of nonmollusks and crustaceans. There were significant differences among stations in mean mollusk abundance and number of mollusk taxa, but the differences showed no evidence of a negative effect of the diffuser effluent on mollusks. For example, mean mollusk abundance was significantly greater at reference station B2 than at ZID station Z or reference stations B1 and B5. Also, there were significantly more mollusk taxa at ZID station Z than at all three reference stations (B1, B2, and B6). Cluster analysis of nonmollusk species composition and abundance showed high similarity (> 65%) among all stations. Two reference stations (B1 and B2) were linked together in a weakly defined subcluster, but the third reference station (B6) was clustered with the ZID and ZID-boundary stations. There was no pattern of lower diversity or evenness for either nonmollusk or mollusk groups at ZID or near-ZID stations relative to the other stations. In fact, the highest diversity and evenness values for both mollusks and nonmollusks were observed at ZID-boundary station B5. The long-term pattern of lower species richness at Station B3, as compared to the other stations, was observed only for the crustacean component and not for other faunal components. The response patterns of benthic fauna near the Sand Island Ocean Outfall showed little indication of a strong influence by the diffuser effluent.

Project Report PR-98-07

Community structure of fish and macrobenthos at selected sites fronting Sand Island Ocean Outfall, Year 8, 1997

Richard E. Brock

January 1998

ABSTRACT

This report provides the results of the eighth year of an annual quantitative monitoring (carried out in August and September 1997) of shallow marine communities inshore of the Sand Island Ocean Outfall, Oahu, Hawaii. This monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Marine communities offshore of Honolulu have received considerable perturbation over the last 100 years. Dumping of raw sewage in shallow water, which occurred from 1955 to 1977, was halted in 1978; however, point and nonpoint sources of pollution from both urban activities and industry continue. All of these disturbances may serve to obscure any impacts that may be caused by treated effluent discharged from the deep-ocean outfall. The marine communities show a considerable range in development that is probably related to historical impacts. Stations have been located to take advantage of these gradients. Analysis of the eight years of data showed that there has been no statistically significant change in the following biological measures: percent coral cover, number of coral species, number of invertebrate species, total number of invertebrates counted, number of fish species, total number of fishes counted, and the biomass of fishes present at each station. Hurricane Iniki, which occurred in September 1992, impacted marine communities along the south shore of Oahu. Coral communities received considerable damage, especially at the westernmost study station. Recovery in these communities is evident from the five years of data collected since the storm. Thus far, this study has not detected a quantifiable negative impact from the operation of the Sand Island Ocean Outfall.

Project Reprot PR-98-06

An analysis of the fish and macrobenthos along the Sand Island Ocean Outfall using remote video: VIII.1997 data

Richard E. Brock

January 1998

ABSTRACT

Because the diffuser of the Sand Island Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the fish and diurnally exposed macrobenthos resident to the diffuser. The use of a remotely operated vehicle is stipulated in the National Pollutant Discharge Elimination System 301(h) waiver permit for the Sand Island Wastewater Treatment Plant. Video reconnaissance was completed over the entire 1,036 m length of the outfall diffuser. Five visual "transects," which "sampled" approximately 41% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser marine communities was carried out annually from 1990 through 1997. Only a few species of diurnally exposed macroinvertebrates are evident on the videotapes of the diffuser; the numbers are insufficient for any meaningful analysis. In 1997, 30 fish species (3,111 individuals) having an estimated biomass ranging from 15 to 90 g/m² (mean 34 g/m²) were censused. In the 1991 through 1996 period the number of fish species encountered during a survey ranged from 22 species (in 1993) to 31 species (in 1992), the total number of individuals from 279 (in 1993) to 2,936 (in 1992), and the mean biomass from 21 g/m² (in 1993) to 92 g/m² (in 1996). Because the 1990 video census covered only the terminal 183 m of the diffuser, whereas the later surveys were spread out along the entire diffuser length, a direct comparison cannot be made between the 1990 data and the data for subsequent years. The 1997 census noted one new fish species for every 11.6 m² of substratum sampled and one fish for every 0.7 m². In the 1991 through 1997 period, measures of the fish community (number of species, number of individuals, and biomass) after an initial increase from 1991 to 1992 and a decrease in 1993 oscillated annually. From a statistical perspective, changes in the mean number of species per transect and the mean number of individual fishes per transect are significant (Kruskal - Wallis ANOVA); changes in the biomass of fishes over the same period are not significant. These changes in the fish community are attributed to changes in the general viewplane of the videotapes recorded in 1994 and later years from that recorded in earlier years, as well as to a change in the resolution of the videotape from which the data are derived. Poorer camera resolution results in lower counts; camera resolution is affected by local wind and currents interacting with the camera, tether, and support vessel as well as by water visibility. Controlling these sources of variation inherent with the use of the remotely operated video system is difficult if not impossible. Until an alternative can be found, the remotely controlled video system is the only low-cost means available to view the marine communities on the diffuser. Until a more accurate means of visual assessment is available, the biological data generated by the remotely operated video camera should be viewed as qualitative, with little statistical rigor.

Project Report PR-98-05

Necropsy and liver histopathology for fish sampled in the vicinity of the Waianae Ocean Outfall, Oahu, Hawaii, September-October 1997

James A. Brock

January 1998

ABSTRACT

Fish liver histopathology is an important biological tool used to assess fish for exposure to pollution. In 1997 gross necropsy and fish liver histopathology were conducted on 10 specimens each of three different fish species: Selar crumenophthalmus, Lutjanus kasmira, and Myripristis spp. These fish were collected live near the terminus of the Waianae Ocean Outfall. Gross or microscopic evidence of neoplasia was not found in the livers of the 30 fish evaluated.

Project Report PR-98-04

Necropsy and liver histopathology for fish sampled in the vicinity of the Barbers Point Ocean Outfall, Oahu, Hawaii, July 1997

James A. Brock

October 1997

ABSTRACT

Fish liver histopathology is an important biological impact that is monitored near the terminus of the Barbers Point Ocean Outfall. In 1997 gross necropsy and fish liver histopathology were conducted on 10 live specimens each of three different fish species: Selar crumenophthalmus, Myripristis spp., and Lutjanus kasmira. Gross evidence of neoplasia was not found in the integument or in the liver of the 30 fish evaluated.

Project Report PR-98-03

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, Oahu, Hawaii, 1997

Anthony R. Russo

October 1997

ABSTRACT

In 1997, coral growth and fish abundance were monitored at stations located at and in the vicinity of the Waianae Ocean Outfall. Comparisons of results with fish surveys done in previous years showed no significant differences in the species composition or relative abundances of fish populations at Station W-2 (the sunken ship Mahi), which is located 1.2 km south of the diffuser. Fish abundance and species richness at Station W-3, which is located at the diffuser, increased from 1990 to 1995, decreased in 1996, and increased again in 1997. At Station WW, an inshore station located 0.8 km from shore, fish were abundant and speciose on the armor rock covering the pipeline. The fish species seen inshore are comparable to fish species seen in similar (boulder) natural biotopes around Hawaii. There were no significant differences in total mean coral cover at selected quadrats from 1994 to 1997 at Station W-2. However, there was a significant increase (8%) in total mean coral cover at this station from 1991 to 1997. At the diffuser, corals were seen growing on the diffuser pipe and on the riser discharge ports. In 1986, when the diffuser began operation at a discharge rate of 1.5 mgd (0.07 m³/s), no corals were seen at this location. At inshore station WW corals off the pipeline were sparsely distributed but were numerous and thriving on the armor rock over the pipeline. The inshore transect (Alpha), off the armor rock, was covered (more than 80%) with the alga Dictyopteris plagiogramma. This seaweed was also abundant at this location in 1995 and 1996. The water was clear at all stations surveyed (13 to 20 m horizontal visibility), and the surrounding sediments were clean and white. No significant deleterious effect due to outfall operation and discharge were seen on the biological community at the stations surveyed. The increase in fish diversity and abundance at the diffuser in 1997 may be due to natural fluctuations in abundance or to environmental conditions suitable to fish populations living there. To distinguish between outfall effects and natural fish population fluctuation patterns, several years of consecutive monitoring must be performed.

Project Report PR-98-02

Benthic sampling adjacent to the Waianae Ocean Outfall, Oahu, Hawaii, October 1996

Anthony R. Russo, E. Alison Kay, Julie H. Bailey - Brock, and William J. Cooke

August 1997

ABSTRACT

In October 1996, bottom samples were collected by scuba divers near the Waianae Ocean Outfall at a depth of approximately 33 m. The Waianae outfall is located on the leeward side of the island of Oahu, Hawaii. The six stations sampled were (1) Station Z, located in the zone of initial dilution (ZID) at the diffuser; (2) Station ZE, located on the southeast boundary of the ZID, about 30 m from the diffuser; (3) Station ZW, located about 60 m southwest of the diffuser; (4) Station W1, located about 2.5 km southeast of the diffuser; (5) Station W2, located about 1.0 km southeast of the diffuser; and (6) Station W9, located about 2.5 km northwest of the diffuser. The bottom at all stations was comprised of more than 90% fine to coarse sand. Station W2 had the coarsest sediments with a relatively high percentage of coral rubble. Oxidation-reduction potential and total volatile solid measurements indicated a nonreducing benthic environment at all stations. A total of 6,949 nonmollusk individuals representing 145 taxa and 8,723 mollusk individuals representing 153 species were recorded. The sediments around the outfall were rich in nematode, oligochaete, polychaete, crustacean, and molluscan fauna. Polychaetes represented 36.8% and crustaceans 9.3% of total nonmollusk abundance. Polychaetes were represented by 80 species and crustaceans by 43. Gastropods comprised more than 90% of total molluscan fauna. The highest mean abundance of nonmollusks was recorded at ZID station ZE and the lowest at ZID station ZW. Mean nonmollusk taxa richness was greatest at station W2, followed by stations Z and ZW, and least at station ZE. Highest mean mollusk abundance was recorded at far-field station W9 and lowest at Station W2. Mean species richness for the mollusk component was highest at Station W9 and lowest at Station W2. The nonmollusk taxa composition was generally similar at all stations. Station ZE was most dissimilar in nonmollusk taxa composition, whereas Stations W1, Z, and W9 were most similar. For mollusks, Station ZE was most dissimilar to the other stations, whereas Stations W1, W2, and W9 were most similar. From 1995 to 1996, there was an increase in nonmollusk taxa richness at Stations W1, W9, and ZW and a decrease at the remaining stations. From 1989 to 1993 the ZID and non-ZID station groups showed parallel shifts in nonmollusk taxa richness, whereas in 1994 non-ZID station group values increased and ZID station group values decreased, such that the values for the two groups converged. The values for both groups remained essentially the same in 1995 and 1996. Mean nonmollusk abundance shifted similarly for ZID and non-ZID station groups among the years of survey, except in 1993 when there was a decrease for the non-ZID station group relative to the ZID station group. In 1995 and 1996 nonmollusk abundance values for the two groups converged. In 1996 total volatile solids, total organic carbon, and total nitrogen concentrations in the sediments near the outfall discharge were lower than in 1995. This is probably due to the shift from primary to secondary treatment of sewage at the Waianae Wastewater Treatment Plant in early 1996. At all stations the sediment was oxygen-rich, as indicated by positive oxidation-reduction potential readings. Mean species richness between ZID and non-ZID station groups was not statistically different. Cluster analysis indicated there was no pattern or grouping of stations, according to species composition, which showed an interaction with the sewage discharge. Near the outfall discharge, no large increase in abundance was found among some species relative to others; the equitability of relative abundances was high at all stations. There was no large decrease in species diversity at stations near the diffuser, as predicted by the Pearson - Rosenberg pollution model. Thus all of the results of the 1996 Waianae benthic study, along with results from previous years, suggest that no deleterious effects occur on the biologically indigenous populations near the outfall from sewage discharge.

Project Report PR-98-01

An analysis of the fish communities along the Barbers Point Ocean Outfall, Ewa Beach, Oahu, Hawaii, using remote video, 1997 data

Richard E. Brock

August 1997

ABSTRACT

Because the diffuser of the Barbers Point Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the marine fish communities and selected diurnally exposed macroinvertebrate species residing on the diffuser. Video reconnaissance was completed over the entire 534-m length. Three visual "transects," which "sampled" approximately 31% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser fish communities was carried out in January of 1992 through 1995, in March of 1996, and in April of 1997. The results of the six annual surveys indicate that the diffuser fish communities are dominated by species that are either small as adults or juveniles of larger species, probably as a result of the presence of only small-scale shelter created by small armor rock and gravel used in constructing the discharge pipe. Because of poor camera resolution, differing angles of the camera, small fish sizes, and the fishesº nature to flee from the approaching camera, the fish census data are highly variable and should be viewed as more qualitative than quantitative in nature. Despite this variability from transect to transect and year to year, only one parameter showed any statistical change over the six annual survey years. This parameter was the mean size of the area sampled to find an individual fish using the nonparametric Kruskal - Wallis analysis of variance. The statistical difference is related to the lower number of individual fish and macroinvertebrates encountered during the 1997 survey, which is related to the ability to see fish due to poor visibility, camera resolution, and camera angle. Little significance should be attached to any change noted in the fish or macrobenthic communities residing on the Barbers Point diffuser because of the variable quality of the data generated by use of the remotely controlled video system.

Project Report PR-97-08

Benthic faunal sampling adjacent to Barbers Point Ocean Outfall, Oahu, Hawaii, January - February 1997

Walter G. Nelson, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

June 1997

ABSTRACT

Benthic infauna in the vicinity of the Barbers Point Ocean Outfall was sampled at seven stations on 30 and 31 January and 4 February 1997 with a modified van Veen grab sampler. The stations were located along the diffuser isobath (61 m) as follows: Station HZ within the zone of initial dilution (ZID); Stations HB2, HB3, and HB4 on the ZID boundary; Station HB6 at 0.5 km from the ZID; and Stations HB1 and HB7 at 3.5 km from the ZID. Sediments were predominantly (>90%) fine to coarse sands. Stations HB1 and HB7 had relatively coarser sediments, and Station HB2 had a higher percentage of silt and clay than the other stations. Total organic carbon in the sediments at all stations was below the detection limit of the analytical method used. Values for oxidation-reduction potential and sediment oil and grease showed no indication of significant organic buildup in sediments at any station. A total of 6,865 nonmollusk individuals from 138 taxa were collected. Polychaetes represented 41.0%, nematodes 28.2%, oligochaetes 13.4%, sipunculans 9.0%, and crustaceans 4.2% of total nonmollusk abundance. Mean total nonmollusk abundance ranged from 122.8 individuals per sample (22,554/m²) at Station HB2 to 259.4 individuals per sample (47,643/m²) at Station HB4. Mean crustacean abundances ranged from 4.2 (926/m²) at Station HB2 to 12.4 (2,733/m²) at Station HB4. Mollusks were analyzed separately because they represent time-averaged collections of live and dead shells. Mean mollusk densities ranged from 152.0 at Station HB2 to 308.0 at Station HB1. From comparisons of nonmollusk abundance among stations, ZID-boundary station HB4 had significantly greater mean abundances than ZID-boundary station HB2. There has been a significant trend of increased abundance for nonmollusks within the entire study area since 1990. Since 1994, there has been a trend of decreased abundance for crustaceans and a trend of increased abundance for mollusks. Significantly elevated abundances of nonmollusks over the entire study period have occurred at two stations near the diffuser relative not only to two of the reference stations but also to a third near-diffuser station. There were no significant differences among stations in number of nonmollusk or crustacean species. Although there were significant differences among stations in number of species for the mollusks, no clear pattern of differences related to proximity to the diffuser was seen among stations. Crustacean taxa richness averaged over the entire study period was lower at stations near the diffuser relative to reference stations. Although not all station differences were significant, the pattern may indicate a trend related to the diffuser. Both diversity and evenness values were generally similar among all stations in 1997 for both nonmollusks and mollusks. Cluster analysis of nonmollusk data confirmed that all stations were relatively similar to one another in terms of species composition and relative abundance. There is no indication of any marked alteration of the benthic community composition related to station proximity to the diffuser.

Project Report PR-97-07

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 1997

Richard E. Brock

May 1997

ABSTRACT

This report provides the results of the sixth year of an annual quantitative monitoring of shallow marine communities inshore of the Barbers Point Ocean Outfall located in 61 m of water offshore of Ewa Beach, Oahu, Hawaii. The monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Field sampling was first carried out in August 1991 when three study stations were established: Station BP-1, a control station 2.2 km inshore and east of the outfall terminus; Station BP-2, an experimental station about 1.5 km inshore of the terminus; and Station BP-3, an experimental station about 2.9 km west and inshore of the terminus. The second field effort, completed in May and September 1993, resurveyed the above stations as well as established a fourth station (BP-4) on and adjacent to the basalt armor caprock protecting the discharge pipe in 13 m of water and directly inshore of the outfall terminus. The third field survey was completed in March and April 1994, the fourth in June 1995, the fifth in May 1996, and the sixth in February and April 1997; each sampled all four stations. These stations are sited to capitalize on presumed gradients of impact that may be created by the discharge and movement of treated sewage effluent toward the shore and the coral reef communities. Data from the first survey suggested that marine communities offshore of Ewa Beach receive disturbance from a number of possible sources, with the largest perturbation probably coming from natural disturbance caused by occasional wave impact. This was most evident at the station directly inshore of the outfall. Data from Station BP-4 showed that benthic communities situated on armor rock which rises above the flat limestone substratum are not subjected to the same sand scour as those situated on the limestone; thus the coral communities on the elevated caprock are better developed on this substrate. A comparison of the data from the six annual surveys indicated that no statistically significant change has occurred in the measured biological parameters at these permanent stations, despite the imposition of a major hurricane on these marine communities in September 1992. Thus the data to date support the contention that the operation of the Barbers Point deep-ocean outfall is not having a quantifiable impact on the coral reef resources situated inshore of the outfall terminus.

Project Report PR-97-06

Benthic faunal sampling adjacent to Sand Island Ocean Outfall, Oahu, Hawaii, September 1996

Walter G. Nelson, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 1997

ABSTRACT

Benthic fauna in the vicinity of the Sand Island Ocean Outfall was sampled at seven stations along the diffuser isobath in September 1996. Stations were located both within and on the boundary of the zone of initial dilution (ZID) and at distances of 1.2 to 2 km from the ZID boundary. Values for total organic carbon, total Kjeldahl nitrogen, and oxidation-reduction potential showed no indication of significant organic buildup in sediments at any station. Correlations between sediment oil and grease from Sand Island samples and both crustacean abundance and species richness showed no evidence of a negative relationship. Mean nonmollusk abundance was significantly greater at Station B2 than at Stations B1 and B6, and mean nonmollusk taxa richness was significantly greater at Station B5 than at Station B1. Station B2 had significantly greater mean crustacean abundance than Stations B3, B1, and Z and greater mean number of crustacean taxa than all other stations. No other pairwise differences in stations for the nonmollusk or crustacean component of the benthic fauna were significant. Therefore, there was no general relationship between nearness to the diffuser and mean nonmollusk or crustacean species richness. Mean mollusk abundance was significantly greater at Station B4, located on the ZID boundary, than at all other stations, and at reference station B2 than at reference station B1 and ZID station Z. Mean mollusk species richness was significantly greater at Stations B5 and Z, respectively located on the ZID boundary and within the ZID, as compared to all other stations, and significantly greater at ZID-boundary station B4 as compared to reference station B1. These patterns show no evidence of a negative effect of the diffuser effluent on mollusks. Cluster analysis of nonmollusk species composition and abundance showed two groupings of stations; one group consisted of two reference stations (B2 and B6), and the second group consisted of the four stations located near the diffuser outfall (B3, B4, B5, and Z). Station B1 was most different from all other stations in 1996. There was no pattern of lower diversity or evenness for either nonmollusk or mollusk groups at ZID or near-ZID stations relative to the other stations. The long-term pattern of lower species richness at Station B3, as compared to the other stations, was observed only for the crustacean component and not for other faunal components. The response patterns of benthic fauna near the Sand Island Ocean Outfall showed little indication of a strong influence by the diffuser effluent.

Project Report PR-97-05

An analysis of the fish and macrobenthos along the Sand Island Ocean Outfall using remote video: VII. 1996 data

Richard E. Brock

March 1997

ABSTRACT

Because the diffuser of the Sand Island Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the fish and diurnally exposed macrobenthos resident to the diffuser. The use of a remotely operated vehicle is stipulated in the National Pollutant Discharge Elimination System 301(h) waiver permit for the Sand Island Wastewater Treatment Plant. Video reconnaissance was completed over the entire 1,036 m length of the outfall diffuser. Five visual "transects," which "sampled" approximately 41% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser marine communities was carried out annually from 1990 through 1996. Only a few species of diurnally exposed macroinvertebrates are evident on the videotapes of the diffuser; the numbers are insufficient for any meaningful analysis. In 1996, 29 fish species (1,931 individuals) having an estimated biomass ranging from 12 to 293 g/m² (mean 92 g/m²) were censused. In the 1991 through 1995 period the number of fish species encountered during a survey ranged from 22 species (in 1993) to 31 species (in 1992), the total number of individuals from 279 (in 1993) to 2,936 (in 1992), and the mean biomass from 21 g/m² (in 1993) to 53 g/m² (in 1992). Because the 1990 video census covered only the terminal 183 m of the diffuser, whereas the later surveys were spread out along the entire diffuser length, a direct comparison cannot be made between the 1990 data and the data for subsequent years. The 1996 census noted one new fish species for every 15.3 m² of substratum sampled and one fish for every 0.7 m². In the 1991 through 1996 period, measures of the fish community (number of species, number of individuals, and biomass) have oscillated annually after an initial increase from 1991 to 1992 and a decrease in 1993. From a statistical perspective, changes in the mean number of species per transect and the mean number of individual fishes per transect are significant (Kruskal - Wallis ANOVA); changes in the biomass of fishes over the same period are not significant. These changes in the fish community are attributed to changes in the general viewplane of the videotapes recorded in 1994 and later years from that recorded in earlier years, as well as to a change in the resolution of the videotape from which the data are derived. Poorer camera resolution results in lower counts; camera resolution is affected by local wind and currents interacting with the camera, tether, and support vessel, as well as by water visibility. Controlling these sources of variation inherent with the use of the remotely operated video system is difficult if not impossible. Until an alternative can be found, the remotely controlled video system is the only low-cost means available to view the marine communities on the diffuser. Until a more accurate means of visual assessment is available, the biological data generated by the remotely operated video camera should be viewed as qualitative, with little statistical rigor.

Project Report PR-97-04

Community structure of fish and macrobenthos at selected sites fronting Sand Island, Oahu, Hawaii, in relation to the Sand Island Ocean Outfall, Year 7, 1996

Richard E. Brock

February 1997

ABSTRACT

This report provides the results of the seventh year of an annual quantitative monitoring (carried out in August and November 1996) of shallow marine communities inshore of the Sand Island Ocean Outfall, Oahu, Hawaii. This monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Marine communities offshore of Honolulu have received considerable perturbation over the last 100 years. Dumping of raw sewage in shallow water, which occurred from 1955 to 1977, was halted in 1978; however, point and nonpoint sources of pollution from both urban activities and industry continue. All of these disturbances may serve to obscure any impacts that may be caused by treated effluent discharged from the deep-ocean outfall. The marine communities show a considerable range in development that is probably related to historical impacts. Stations have been located to take advantage of these gradients. Analysis of the seven years of data showed that there has been no statistically significant change in the following biological measures: percent coral cover, number of coral species, number of invertebrate species, total number of invertebrates counted, number of fish species, total number of fishes counted, and the biomass of fishes present at each station. Hurricane Iniki, which occurred in September 1992, impacted marine communities along the south shore of Oahu. Coral communities received considerable damage, especially at the westernmost study station. Recovery in these communities is evident from the four years of data collected since the storm. Thus far, this study has not detected a quantifiable negative impact from the operation of the Sand Island Ocean Outfall.

Project Report PR-97-03

A survey of selected coral and fish assemblages near the Waianae Ocean Outfall, Oahu, Hawaii, 1996

Anthony R. Russo

November 1996

ABSTRACT

In 1996, coral growth and fish abundance were monitored at stations located at and in the vicinity of the Waianae Ocean Outfall. Comparisons of results with fish surveys done in previous years showed no significant differences in the species composition or relative abundances of fish populations at Station W-2 (the sunken ship Mahi), which is located 1.2 km south of the diffuser. Fish abundance and species richness increased at Station W-3, which is located at the diffuser, from 1990 to 1995 and decreased in 1996. At Station WW, an inshore station located 0.8 km from shore, fish were abundant and speciose on the armor rock covering the pipeline. The fish species seen inshore are comparable to fish species seen in similar (boulder) natural biotopes around Hawaii. There were no significant differences in total mean coral cover at selected quadrats from 1994 to 1996 at Station W-2. However, there was a significant increase (8%) in total mean coral cover at this station from 1991 to 1996. At the diffuser, corals were seen growing on the diffuser pipe and on the riser discharge ports. In 1986, when the diffuser began operation at a discharge rate of 1.5 mgd (0.07 m³/s), no corals were seen at this location. At inshore station WW corals off the pipeline were sparsely distributed but were numerous and thriving on the armor rock over the pipeline. The inshore transect (Alpha), off the armor rock, was covered (more than 40%) with the alga Dictyopteris plagiogramma. This seaweed was also seen at this location in 1994 and 1995. The water was clear at all stations surveyed (10 to 15 m horizontal visibility), and the surrounding sediments were clean and white. No significant deleterious effect due to outfall operation and discharge were seen on the biological community at the stations surveyed. The decrease in fish diversity and abundance at the diffuser may be due to natural fluctuations in fish abundance. To distinguish between outfall effects and natural fish population fluctuation patterns, several years of consecutive monitoring must be performed.

Project Report PR-97-02

Community structure of fish and macrobenthos at selected shallow-water sites in relation to the Barbers Point Ocean Outfall, 1996

Richard E. Brock

November 1996

ABSTRACT

This report provides the results of the fifth year of an annual quantitative monitoring of shallow marine communities inshore of the Barbers Point Ocean Outfall located in 61 m of water offshore of Ewa Beach, Oahu, Hawaii. The monitoring effort focuses on benthic and fish community structure and is designed to detect changes in these communities. Field sampling was first carried out in August 1991 when three study stations were established: Station BP-1, a control station 2.2 km east and inshore of the outfall terminus; Station BP-2, an experimental station about 1.5 km inshore of the terminus; and Station BP-3, an experimental station about 2.9 km west and inshore of the terminus. The second field effort, completed in May and September 1993, resurveyed the above stations as well as established a fourth station (BP-4) on and adjacent to the basalt armor caprock protecting the discharge pipe in 13 m of water and directly inshore of the outfall terminus. The third field survey was completed in March and April 1994, the fourth in June 1995, and the fifth in May 1996; each sampled all four stations. These stations are sited to capitalize on presumed gradients of impact that may be created by the discharge and movement of treated sewage effluent toward the shore and the coral reef communities. Data from the first survey suggested that marine communities offshore of ÂEwa Beach receive disturbance from a number of possible sources, with the largest perturbation probably coming from natural disturbance caused by occasional wave impact. This was most evident at the station directly inshore of the outfall. Data from Station BP-4 showed that benthic communities situated on armor rock which rises above the flat limestone substratum are not subjected to the same sand scour as those situated on the limestone; thus the coral communities on the elevated caprock are better developed on this substrate. A comparison of the data from the five surveys indicated that no statistically significant change has occurred in the measured biological parameters at these permanent stations, despite the imposition of a major hurricane on these marine communities in September 1992. Thus the data to date support the contention that the operation of the Barbers Point deep-ocean outfall is not having a quantifiable impact on the coral reef resources situated inshore of the outfall terminus.

Project Report PR-97-01

An analysis of the fish communities along the Barbers Point Ocean Outfall, Ewa Beach, Oahu, Hawaii, using remote video, 1996 data

Richard E. Brock

October 1996

ABSTRACT

Because the diffuser of the Barbers Point Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the marine fish communities and selected diurnally exposed macroinvertebrate species residing on the diffuser. Video reconnaissance was completed over the entire 534-m length. Three visual "transects," which "sampled" approximately 31% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser fish communities was carried out in January of each year from 1992 through 1995 and in March of 1996. The results of the five annual surveys indicate that the diffuser fish communities are dominated by species that are either small as adults or juveniles of larger species, probably as a result of the presence of only small-scale shelter created by small armor rock and gravel used in constructing the discharge pipe. Because of poor camera resolution, differing angles of the camera, small fish sizes, and the fishesº nature to flee from the approaching camera, the fish census data are highly variable and should be viewed as more qualitative than quantitative in nature. Despite this variability from transect to transect and year to year, only one parameter showed any statistical change over the five annual survey years. This parameter was the mean size of the area sampled to find an individual fish. Little significance should be attached to any change noted in the fish or macrobenthic communities residing on the Barbers Point diffuser because of the variable quality of the data generated by use of the remotely controlled video system.

Project Report PR-96-09

A study of the impact of Hurricane Iniki on coral communities at selected sites in Mamala Bay, Oahu, Hawaii

Richard E. Brock

June 1996

ABSTRACT

Mamala Bay on Oahuºs south shore is the receiving body for sewage effluent discharged from two deep-ocean outfalls, the Sand Island Ocean Outfall and Barbers Point Ocean Outfall. The effluent, after receiving primary treatment at the Sand Island and Honouliuli wastewater treatment plants, is discharged about 2.7 km from shore at depths of 61 m and 71 m, respectively. The coral reef communities inshore of these outfalls are monitored at a number of permanently marked stations that take advantage of any shoreward gradient of stress that may emanate from these two point source discharges. Hurricane Iniki, which occurred in 1992, impacted coral reef communities in Mamala Bay and elsewhere. The damage caused by this storm could serve to obscure impacts due to the operation of the outfalls, and/or the decline in coral coverage could be construed as being the result of the operation of the outfalls. This study was undertaken to address these concerns. The study results revealed that pre-Iniki coral communities in Mamala Bay were not well-developed due to the occasional impact of storm-generated surf. Hurricane Iniki contributed to a decrease in coral coverage to varying degrees, with less impact in areas where local submarine topography served to protect corals from storm damage. Despite varying degrees of local impact, recovery in Mamala Bay coral communities was similar, irrespective of location or method of measurement. Recovery was measured by recording changes in coral coverage in permanently marked quadrats as well as changes in growth rates of marked and transplanted corals. The lack of significant differences in any of the growth parameters measured in this study between sites suggests that environmental parameters that may influence coral growth probably do not differ much between these locations. The recovery of corals at all sites following the hurricane was statistically similar, suggesting no negative influence from the operation of the deep-ocean outfalls. The greatest change attributable to the hurricane at the sites examined in this study was the loss of topographical relief and shelter habitat for many fish and invertebrate species. This loss was caused by the movement of loose materials (rubble and sand) across the bottom; their settling into depressions resulted in a less heterogeneous habitat. However, loss of habitat due to infilling is only one aspect of a continuum; major storm events may create topographical complexity and shelter space by uncovering previously buried substratum.

Project Report PR-96-08

Benthic faunal sampling adjacent to Barbers Point Ocean Outfall, Oahu, Hawaii, January 1996

Walter G. Nelson, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

May 1996

ABSTRACT

Benthic infauna in the vicinity of the Barbers Point Ocean Outfall was sampled at seven stations on 11 and 12 January 1996 with a modified Van Veen grab sampler. The stations were located along the diffuser isobath (61 m) as follows: Station HZ within the zone of initial dilution (ZID); Stations HB2, HB3, and HB4 on the ZID boundary; Station HB6 at 0.5 km from the ZID; and Stations HB1 and HB7 at 3.5 km from the ZID. Sediments were predominantly (>90%) fine to coarse sands. Station HB7 had relatively coarser sediments and Station HB2 had a higher percentage of silt and clay than the other stations. Total organic carbon in the sediments at all stations was below the detection limit of the analytical method used. Values for oxidation-reduction potential and sediment oil and grease showed no indication of significant organic buildup in sediments at any station. A total of 8,727 nonmollusk individuals from 147 taxa were collected. Polychaetes represented 44.0%, nematodes 28.6%, oligochaetes 13.2%, and crustaceans 7.5% of total nonmollusk abundance. Mean total nonmollusk abundance ranged from 121.2 individuals per sample (22,371/m²) at Station HB7 to 347.0 individuals per sample (64,246/m²) at Station HZ. Mean crustacean abundances ranged from 13.8 (3,041/m²) at Station HZ to 25.0 (5,510/m²) at Station HB1. Mollusks were analyzed separately because they represent time-averaged collections of live and dead shells. Mean mollusk densities ranged from 173.6 at Station HB2 to 279.6 at Station HB4. From comparisons of nonmollusk abundance among stations, ZID-boundary station HB4 and ZID station HZ had significantly greater mean abundances than reference station HB7. There has been a significant trend of increased abundance of nonmollusks within the entire study area since 1990, although there has been no trend either for the crustacean component of the nonmollusks or for the mollusks. Significantly elevated abundances of nonmollusks over the entire study period have occurred at two stations near the diffuser relative not only to two of the reference stations but also to a third near-diffuser station. There were no significant differences among stations in number of nonmollusk or crustacean species. Although there were significant differences among stations in number of species for the mollusks, no clear pattern of differences related to proximity to the diffuser was seen among stations. Both diversity and evenness values were generally similar among all stations for both nonmollusks and mollusks. Cluster analysis of nonmollusk data confirmed that all stations were relatively similar to one another in terms of species composition and relative abundance. There is no indication of any marked alteration of the benthic community composition related to station proximity to the diffuser.

Project Report PR-96-07

Benthic faunal sampling adjacent to Sand Island Ocean Outfall, Oahu, Hawaii, August 1995

Walter G. Nelson, Julie H. Bailey - Brock, William J. Cooke, and E. Alison Kay

March 1996

ABSTRACT

Benthic fauna in the vicinity of the Sand Island Ocean Outfall was sampled at seven stations along the diffuser isobath in August 1995. Stations were located both within and on the boundary of the zone of initial dilution (ZID) and at distances of 1.2 to 2 km from the ZID boundary. Values for total organic carbon, total Kjeldahl nitrogen, and oxidation-reduction potential showed no indication of significant organic buildup in sediments at any station. Correlations between sediment oil and grease from Sand Island samples and both crustacean abundance and species richness were not significant. Mean nonmollusk abundance and crustacean abundance did not differ significantly among stations. Mean nonmollusk species richness was not significantly different among stations. Mean crustacean species richness was significantly lower at Station B3 as compared only to reference station B1. Therefore, there was no general relationship between nearness to the diffuser and mean nonmollusk or crustacean species richness. Mean mollusk abundance was significantly greater at Station B4, located on the ZID boundary, than at reference station B1 or Station B5, located near the ZID. Mean mollusk species richness was highest at Stations B5 and Z, located either on the ZID boundary or within the ZID, as compared to most other stations. These patterns are the reverse of those expected as a result of an impact related to the diffuser effluent. Cluster analysis of nonmollusk species composition and abundance showed two groupings of stations; the three reference stations formed one group and the four stations near the diffuser formed a second group. In 1994, reference station B2 was grouped with the ZID and near-ZID stations. There was no pattern of lower diversity or evenness for either nonmollusk or mollusk groups at ZID or near-ZID stations relative to the other stations. The long-term pattern of lower species richness at Station B3, as compared to the other stations, was observed only for crustacean species richness and not for other faunal components. The response patterns of benthic fauna near the Sand Island Ocean Outfall showed little indication of a strong influence by the diffuser effluent.

Project Report PR-96-06

An analysis of the fish and macrobenthos along the Sand Island Ocean Outfall using remote video: VI. 1995 data

Richard E. Brock

March 1996

ABSTRACT

Because the diffuser of the Sand Island Ocean Outfall lies below safe diving depths, a remotely controlled video camera system was used to determine the status of the fish and diurnally exposed macrobenthos resident to the diffuser. The use of a remotely operated vehicle is stipulated in the National Pollutant Discharge Elimination System 301(h) waiver permit for the Sand Island Wastewater Treatment Plant. Video reconnaissance was completed over the entire 1,036 m length of the outfall diffuser. Five visual "transects," which "sampled" approximately 41% of the total diffuser length, were established on the diffuser pipe. Video sampling of the diffuser marine communities was carried out annually from 1990 to 1995. Only a few species of diurnally exposed macroinvertebrates are evident on the videotapes of the diffuser; the numbers are insufficient for any meaningful analysis. In 1995, 25 fish species (1,796 individuals) having an estimated biomass ranging from 19 to 51 g/m² (mean 30 g/m²) were