Abstract
The toxicity of cadmium to sticklebacks was determined over a wide range of concentrations. The 96 h LC50 was found to be 6.5 mg Cd I−1. The shape of the time‐concentration curve suggests that cadmium may have two toxic mechanisms. The median period of survival for fish infected with the plerocercoids of the cestode, Schistocephalus solidus, was found to be considerably shorter than for non‐parasitized fish. This observation is considered in the light of the known effects of 5. solidus on its host.