Intensity of parasitic nematodes increases with organochlorine levels in the glaucous gull.
Forty adult glaucous gulls Larus hyperboreus were collected on Bear Island, Norway, in the Svalbard archipelago in the western Barents Sea in July 1996. Concentrations of 9 selected polychlorinated biphenyls (PCB; 28, 52, 99, 101, 118, 138, 153, 170 and 180) and 5 chlorinated pesticides (hexachlorobenzene, oxychlordane, DDE, DDT and Mirex) were measured in the liver. The abundance of 12 species of intestinal helminths, including 1 trematode (Cryptocotyle lingua), 6 cestodes (Anomotaenia micracantha, Alcataenia dominicana, Paricterotaenia porosa, Microsomacanthus ductilis, Aploparaksis larina, Tetrabothrius erostris), 4 nematodes (Anisakis simplex, Contracaecum osculatum, Paracuaria adunca, Stegophorus stellaepolaris) and 1 acanthocephalan (Corynosoma strumosum), was determined. After controlling for nutritional condition, no single parasite species was significantly associated with concentrations of PCB or chlorinated pesticides. However, the intensity of all nematodes grouped together was positively correlated with 10 of the 14 organochlorine concentrations measured. The strongest correlations were with p,p′-DDT, Mirex, Σ9PCB, and PCB congeners 28, 118, 153, 138, 170 and 180. Although correlative, and collected in the absence of immunological data, these data do not refute the hypothesis that organochlorines might affect avian immune function.