No abstract

No abstract

A simple sperm/fertilization bioassay, primarily using sea urchin gametes, has been developed and used by a variety of laboratories. This assay was recently refined into a standard test and is now being used by the U.S. Environmental Protection Agency and others for toxicity testing in marine waters. One factor that has lagged behind the development of this assay is the comparison of its sensitivity to various common toxicants as compared to other bioassay systems and life stages of other marine organisms. The objective of this study was to compare the sensitivity of a standardized sea urchin sperm/fertilization assay to the responses of embryo, larval, and adult marine organisms to metals (Ag, Cd, Cu, Pb, Zn) and pesticides (DDT, Dieldrin, Endrin, Endosulfan) added to natural seawater. The results, although highly variable, generally showed that sperm/fertilization and embryo assays were quite sensitive to the metals tested, but that the larval and adult assays were more sensitive to the pesticides. These comparative data, together with other studies of complex effluents, show that the standardized sperm/fertilization bioassay is an especially quick and useful tool for biomonitoring of marine waters.

Concerns about possibly heavy impacts of bottom trawl fisheries on red king crab (Paralithodes camtschaticus) pot fisheries in the eastern Bering Sea led in 1987 to an emergency closure of trawling in an area of adult and juvenile crab habitat. We examine the effectiveness of this bycatch refuge in protecting and possibly enhancing the crab resource using three approaches. First, bycatch of crab in trawl fisheries is a small proportion of total estimated abundance throughout the southeastern Bering Sea but may be high relative to stock abundance within the closed area and relative to annual crab landings; recent regulations have diminished this apparent effect. Effects of direct bycatch on the stock are obscured by lack of evidence on indirect effects of trawling, including crushing of crab and degredation of juvenile habitat. Second, surveys inside and outside the refuge before and after closure show no significant changes in abundance of female and prerecruit male crab. Third, important breeding and hatching grounds and juvenile habitat are not protected by the refuge, leaving long-term stock renewal subject to trawl impacts. We suggest that full consideration of the needs of all life history stages could lead to a more effective refuge design.