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 oft en 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 s ensitive (N = 4 studies) to organochlorines and 5 times more sensitive (N = 17 studies) to organophosphates than were mysids. Acute exposures of less than or equal to 24-h-old mysids and second postlarval pink s hrimp Penaeus duorarum were conducted to compare responses of these cr ustaceans to each other, and to values from the literature for other e stuarine crustaceans. The test compounds were chloride salts of cadmiu m, copper, and zinc; the organophosphates diazinon, fenthion, and mala thion; and several pyrethroids - cypermethrin, fenvalerate, and permet hrin. Results showed that pyrethroid toxicities to mysids and postlarv al pink shrimp were similar, organophosphate toxicities were within a factor of 2.6 for both species, and mysids were 3 to 26 times more sen sitive to the metals than were larval pink shrimp.