Effects of addition of a bird repellent to fish diets on their growth and bioaccumulation

Abstract

The eiects of adding the nonlethal bird repellent methyl anthranilate (MA), at levels of 100 and 1000 mg kg 1 , to ¢sh feed on the bioaccumulation and growth of juvenile (10 g) hybrid striped bass (Morone chrysops M. saxatilis) and juvenile (1g) African cichlid ¢sh Aulonocara jacobfreibergi were investigated under laboratory conditions. The bird repellent did not have any eiect on the ¢sh growth or survival over a period of 6 weeks. MA residues at low levels of 11.2 2.6 m gg 1 were found in lipophilic tissues (liver) of MA-fed ¢sh. Control ¢sh, which had no MA added to their diet, had a much lower level of 0.6 0.3 m gg 1 MA in their liver. Fish muscle was found to contain negligible MA residues, while the outer body surface mucus did not contain any MA. Following a 6-week depuration period, during which the previously MA-fed hybrid striped bass were fed a feed to which no MA was added, the levels of MA residues detected were reduced by one order of magnitude.