Visual track census and a new method, acoustic counting, were used to estimate the humpback whale (Megaptera novaeangliae) population in the West Indies. Results produced by the two methods differed to some extent. The average or best estimate was 1018 whales with a range of 785–1157. Silver and Navidad banks, containing approximately 85% of the total population, are presently the major nursery grounds in the West Indies. The humpback whale population in the western North Atlantic has increased since the early part of the century.
DDT, PCBs, chlordane, and dieldrin levels were measured in blubber of 18 cetaceans, including humpback, sperm, dense-beaked, Atlantic, and Pacific pilot whales, and five species of dolphins. All had significant residue levels, ranging from 1.1 to 1023 ppm ΣDDT (wet weight basis), and 0.7–147 ppm PCBs. These levels are high enough to justify efforts to reduce PCB contamination of the oceans and a continued ban on widespread use of DDT.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.