Comparative acute toxicities of several pesticides and metals to Mysidopsis bahia and postlarval penaeus duorarum

Effects of toxic chemicals on estuarine and marine crustaceans are often evaluated using the mysid Mysidopsis bahia . In a literature survey of results of acute toxicity tests with estuarine crustaceans, Mysidae and Penaeidae were generally the two most sensitive families. However, neither family was consistently more sensitive (higher LC50 divided by lower LC50 > 2). Mysids were 54 times more sensitive to pyrethroids than were penaeids ( N = 3 studies). Yet penaeids were 36 times more sensitive ( N = 4 studies) to organochlorines and 5 times more sensitive ( N = 17 studies) to organophosphates than were mysids. Acute exposures of ≤24‐h‐old mysids and second postlarval pink shrimp Penaeus duorarum were conducted to compare responses of these crustaceans to each other, and to values from the literature for other estuarine crustaceans. The test compounds were chloride salts of cadmium, copper, and zinc; the organophosphates diazinon, fenthion, and malathion; and several pyrethroids – cypermethrin, fenvalerate, and permethrin. Results showed that pyrethroid toxicities to mysids and postlarval pink shrimp were similar, organophosphate toxicities were within a factor of 2.6 for both species, and mysids were 3 to 26 times more sensitive to the metals than were larval pink shrimp.