Table 39. Maximum and minimum site means, total ranges among site means, averages of the 

 site SDs and CVs, and the quotient of dividing the range by the average SD for selected 

 bioeffects measures in Platichthys stellatus. 



* November - December fish 



DISCUSSION AND CONCLUSIONS 



Sediment Toxicity Tests 



Mytilus edulis. The bivalve larvae bioassay was initially developed for use in testing the 

 toxicity of water and effluents, particularly pulp mill wastes in Puget Sound. Its initial use 

 in sediment tests was reported by Chapman and Morgan, 1983. The embryos of oysters were 

 initially used in the tests. The test has been used as a relatively quick and inexpensive 

 indicator of sediment toxicity. Embryos generally can be acquired throughout most of the 

 year, although with more difficulty during the winter. However, since the embryos of both 

 oysters and mussels do not seek and colonize soft-bottom sediments, the test may be most 

 appropriately viewed as an indicator test with less ecological relevance than, say, a solid 

 phase test with an infaunal or epibenthic species. Protocols have been developed for the 

 performance of the test. These protocols (Chapman and Becker, 1986), specify that at least 

 70 percent of the larvae must survive in seawater controls and that at least 90 percent of the 

 larvae develop normally. These protocols recommended that either oyster larvae or mussel 

 larvae could be used in the tests. 



Out of 60 stations sampled in the industrial waterways of Commencement Bay, normal 

 development of oyster larvae was 70 percent or less in samples from 18 (30%) of the stations 

 (Williams et a\., 1986). No normal larvae were observed in a test of one of the stations, less 

 than 40 percent were normal in tests of five of the stations. In four samples from a rural 

 reference area, Carr Inlet, mean percent normal development was 87 percent. About 96 

 percent of the larvae developed normally in seawater controls. In other research conducted 

 in Puget Sound, less than 80 percent normal development was observed in 3 of 10 (30%) 

 stations sampled in Bellingham Bay, 3 of 6 (50%) stations sampled in Everett Inner Harbor, 

 4 of 4 (100%) stations sampled in the Duwamish Waterway near Seattle, and 6 of 9 (67%) 

 stations sampled in the Commencement Bay waterways (Long, 1985). Mean normal 

 development was less than 40 percent in samples from Islais Waterway, off Port of San 

 Francisco piers 94/96, off Hunters Point, and off Treasure Island tested with oyster or mussel 

 larvae by various investigators (Long et al., 1988). By comparison, mean normal development 



79 



