Effects of dietary copper on the Australian freshwater crayfish Cherax destructor

Little information is available on the effects of metals in the diet of par astacids, despite the importance of the freshwater crayfish industry worldw ide. There have been no published studies on the effect of either dissolved or dietary copper on the Australian freshwater crayfish Cherax destructor. Herein is reported a study on the bioaccumulation of copper through a simp le food chain. The copper was first absorbed by the floating aquatic macrop hyte Lemna minor to an average concentration of 74 mu g/g, before being fed to C. destructor. Tn the crayfish, the highest copper concentrations were found in the muscle (56.4-1299.6 mu g/g), gills (86.8-714.3 mu g/g) and bem olymph (14.8-1293.5 mu g/g). There was no bioaccumulation or bioconcentrati on of copper from contaminated dietary material. A general linear model ind icated that such treatment had no effect on copper concentrations in the cr ayfish. The results are consistent with the regulation of copper by C. dest ructor, with the gills being the main site for absorption and depuration of copper to and from the water column. C. destructor does not appear to be s ensitive to dietary copper. (C) 2000 Academic Press.