Project Report PR-94-10
A Survey of Selected Coral and Fish Assemblages Near the Waianae Ocean Outfall, Oahu, Hawaii, 1993
Anthony R. Russo
In 1993, coral growth and fish abundance were monitored at stations located at and in the vicinity of the Waianae Ocean Outfall. Comparison of the 1993 results with fish surveys done in previous years showed no significant differences in the species composition or relative abundances of fish populations at the outfall diffuser and at a station 1.2 km south of the diffuser (the sunken ship Mahi). Fish species were essentially the same as those seen in similar natural biotopes around Hawaii. There were no significant differences in total coral cover from 1992 to 1993 at the station 1.2 km south of the diffuser. In 1986, when the diffuser began operation, no corals were seen at the diffuser; however, in 1993 corals were seen growing on the diffuser pipe and on the riser discharge ports. The water was clear at all stations surveyed (10 to 15 m horizontal visibility), and the sediments were clean and white. No significant deleterious effects resulting from outfall operation and discharge were seen on the biological community at the stations surveyed.