Associate Water Quality Biologist, Aquatic Toxicology Laboratory, Elk Grove, CA
Environmental Services Supervisor, Aquatic Toxicology Laboratory, Elk Grove, CA
Aquatic Biologist, U.S. Environmental Protection Agency, Environmental Research Laboratory, Newport, OR
Pages: 19 Published: Jan 1991
Striped bass (Morone saxatilis) appear to be a desirable test species for the estuarine environment because their critical life stages are spent in estuaries, they have wide tolerance to salinity, and they are available through government and private hatcheries. Toxicity test procedures and life stage sensitivity were evaluated based upon results from acute (96-h) and chronic (36-d) larvae-to-fry and (45-d) embryos-to-fry tests. Striped bass larvae can suffer significant control mortality, but acceptable results were the rule when tests were conducted with larvae greater than 10-d posthatch and with dilution water of alkalinity and hardness between 110 to 150 mg/L (CaCO3) and slightly saline (2‰). Replicate tests with molinate, thiobencarb, and endosulfan resulted in coefficients of variation for 96-h LC50 values of less than 30%. Striped bass larvae were more sensitive to several pesticides than chinook salmon (Oncorhynchus tshawytscha) fry. Lower 96-h LC50 (μg/L) values were obtained using striped bass larvae compared to chinook salmon fry for a variety of pesticides including carbofuran (210 versus 610), thiobencarb (730 versus 760), molinate (9400 versus 13 000), endosulfan (0.31 versus 0.74), and malathion (47 versus 101). Striped bass larvae-to-fry and chinook salmon embryos-to-fry had similar sensitivity to molinate and to thiobencarb; MATC values ((NOEC × LOEC)½) were 290 and 170 μg/L molinate and <27 to 73 and 37 μg/L thiobencarb, respectively.
acute toxicity, striped bass, chinook salmon, chronic toxicity, copper, malathion, molinate, thiobencarb, endosulfan, carbofuran
Paper ID: STP23573S