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Arctic cod (Boreogadus saida) were captured by bottom trawl at depths of 120–300 m. Zooplankton were obtained by bottom to surface tows from the Arctic cod habitat. Average concentrations of arsenic (As) and zinc (Zn) were higher in Arctic cod fillets than in livers from the same fish; cadmium (Cd) and iron (Fe) concentrations were higher in livers. The difference between copper (Cu) concentrations in muscle and liver was not significant. As and Zn in whole fish, and As in fillets from seven specimens, were positively correlated to body weight. Cu and Fe in whole fish were negatively correlated to body weight, whereas Cd was not related to body weight. Examination of Arctic cod stomach contents indicated that planktonic copepods were important in the diet. Cd levels were 5–8 times higher in the unsorted copepods than in the Arctic cod, whereas As, Cu, Fe, and Zn were higher in the fish than in the copepods.

The lower mainland waterways of British Columbia are inhabited by two races of prickly sculpin, Cottus asper. The "coastal" race, which has a generally smooth skin, lives in the lower part of the rivers or estuaries and spends at least part of its life (particularly during the spawning season) under tidal conditions. The "inland" race, which displays a marked dermal "prickling", is confined entirely to freshwater, where it is found in scattered, more or less isolated populations, In freshwater the thyroid glands of both races are relatively quiescent, but with increasing salinity, particularly in a hyperosmotic environment, there is a marked increase in the uptake of tracer iodine by the thyroid and an elevation in the levels of circulating hormone. The inland fish have a greater ability than do the coastal fish to retain injected iodides in freshwater; in seawater the thyroids of the inland fish appear to be more active than do those of the coastal forms. The findings indicate a genetic divergence resulting in a relatively greater capacity of the inland fish to retain electrolytes.