Pesticide Residues in a Marine Population of Double-Crested Cormorants

Abstract

The double-crested cormorant (Phalacrocorax auritus) was successful in its reproduction in Muscongus Bay, Maine, colonies in 1966 despite the fact that gulls and exposure inflicted a high mortality (71 percent) on eggs and young. The cormorant obtained little or no pesticide from Maine fish. Pesticides present in the organs of the cormorant were obtained in some other area, possibly Florida where the bird winters. Pesticide residues seem not to have affected the reproductive success of the cormorant. It has been suggested that pesticide residues in the fishes upon which the osprey (Pandion haliaetus) (Ames and Mersereau 1964) and the bald eagle (Haliaeetus leucocephalus) (Broley 1958) feed may be responsible for these bird's decline in pro1 This research was supported by the Department of Conservation at Cornell University, the Department of Food Science and Technology at the New York State Agricultural Experiment Station, the Patuxent Wildlife Research Center of the Bureau of Sport Fisheries and Wildlife, the American Museum of Natural History (Chapman Fund), the Wildlife Management Institute, the Mercersburg Academy, the National Audubon Society, and the Conococheaque Naturalists. s been sug ested that pesticide resii the fishes upon which the osprey ductivity. Rather poor nesting success of the osprey has been noted for Muscongus Bay, Maine (Kury 1966). Other piscivorous birds, particularly the double-crested cormorant, appeared to be unaffected. To study this inconsistency, levels of pesticide in the cormorant and its food were measured as well as cormorant nesting success in the Muscongus Bay colonies. Some work was done in Penobscot Bay and samples were collected on the Isles of Shoals. R. Clark performed the gas chromatographic analyses. W. 0. Allen, 0. H. Hewitt, G. L. Mack, and G. A. Swanson were . at er poor nesting suc es of as been noted for Muscongus i ( ury 1966). Other piscivorous ic larly the double-crested corThis content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 06:13:23 UTC All use subject to http://about.jstor.org/terms 92 Journal of Wildlife Management, Vol. 33, No. 1, January 1969 Table 1. Pesticide residues in double-crested cormorants expressed in ppm. No. OF SAMPLES IN WHICH No. OF No. OF ARITH. ALSO PRESENT SAMPLES INDIVIDUALS PESTIMEAN Year LOCALITY TYPE ANALYZED ANALYZED CIDE ? SD RANGE DDT DDD 1966 Mus. B. 9 brain 11 11 DDE 2.0 ? 0.4 0.6 5.3 0