Mysids, small shrimp-like crustacea, proved to be a practical bioassay animal for investigating the effects of cadmium in seawater and may serve this purpose for other pollutants. In the laboratory under flow-through test conditions, the mysid, Mysidopsis bahia, was more sensitive to cadmium than other crustaceans tested. LC50 values were 15.5 microgram/l within 96 hrs and 11.3 microgram/l during a 17-day life cycle, whereas LC50's for other selected crustaceans were between 120 and 720 microgram/l. Results of life-cycle bioassays can aid in the establishment of water quality criteria for marine and estuarine organisms.

This study documents the successful use of a mysid, Mysidopsis bahia, for life-cycle toxicity tests. These tests were conducted to determine acute and chronic toxicities of metal (cadmium) and pesticide (Kepone). Delay in the formation of mysid brood pouches and release of young were noted in low concentrations ⩽6.4μg cadmium/litre. Fewer young produced per female and decreased growth were other indicators of effects of Kepone.

Flow-through, acute (96-h), and early life stage (28-d after hatch) toxicity tests were performed with eight chemical on a saltwater fish, sheepshead minnows (Cyprinodon variegatus). Chemical effects on survival, growth, and development were determined. Maximum acceptable toxicant concentrations (MATCs) were greater than 3.2 less than 7.7 mg/l for toluene, greater than 0.52 greater than 0.97 mg/l for acenaphthene, greater than 80 less than 156 mg/l for isophorone, greater than 10 less than 16 mg/l for 4-nitrophenol, greater than 4.8 less than 8.5 mg/l for bromoform, greater than 0.39 less than 0.79 mg/l for 1-chloronaphthalene, greater than 0.09 less than 0.18 mg/l for 1, 2, 4, 5-tetrachlorobenzene, and less than 0.36 mg/l for 2, 4-dichloro-6-methylphenol; application factors were 0.25-0.59, 0.17-0.31, greater than or equal to 0.57, 0.31-0.50, greater than or equal to 0.68, greater than or equal to 0.56, 0.27-0.54, and less than 0.10. respectively. Test results reported here were compared with results of static, acute toxicity tests conducted previously with six species of aquatic organisms and the same chemicals.