ORGANOCHLORINE AND METAL CONTAMINANTS IN BALEEN WHALES - A REVIEW ANDEVALUATION OF CONSERVATION IMPLICATIONS

The literature on organochlorine and metal contaminants in tissues of baleen whales includes data for approximately 1000 individuals in 10 s pecies from various oceans of the world. Concentrations of these conta minants in tissues of baleen whales are low. Sources of variation in o rganochlorine concentrations in whales include age, sex, region of exp osure, and feeding habits. Concentrations of SIGMADDT and PCBs in bale en whales appear higher in the northern hemisphere than in the souther n oceans, perhaps due to greater contamination of northern ecosystems and a higher incidence of fish in the diet. However, maximum concentra tions are generally lower in tissues of baleen whales than in other ma rine mammal species, both on global and local scales. This is predicta ble based on the general distribution, habitats and trophic levels of baleen whales. We reviewed laboratory studies on the effects of select ed organochlorine contaminants on direct mortality and impaired reprod uction in other mammals, and critically examined observations attempti ng to link organochlorines to reproductive and population effects in m arine mammals. There is no firm basis to conclude that the contaminant s reviewed herein have affected baleen whale populations. Although mor e information on contaminants in baleen whales would be of value, as a matter of priority, research and management actions should focus on r educing human-caused mortality and increasing habitat carrying capacit y for these species.