The effects of in vitro exposure to different organochlorines were evaluated on immune functions of beluga whale peripheral blood leukocytes and splenocytes. The effects of different concentrations of four different congeners of PCBs (138, 153, 180, and 169) as well as two DDT metabolites (p,p'-DDT and p,p'-DDE) were evaluated on phagocytosis and cell proliferation. The effects of dioxins and m...

Toxoplasmosis was diagnosed in two free-ranging beluga whales from the St Lawrence estuary, Quebec, Canada, in 1988 and 1998. Histologically, tachyzoites and bradyzoites were present in the brain, spleen, lymph nodes, adrenals and lungs of both animals, and in the thymus of one. These organisms were readily labelled by an indirect immunohistochemical method for Toxoplasma gondii antigens. In th...

James, Hudson and Ungava bays are summering areas for stocks of beluga whales (Delphinapterus leucas) (Sergeant and Brodie, 1975; Finley et al., 1982; Smith and Hammill, 1986; Richard et al., 1990). There are several apparently separate summer groups, which include a summer group of ~23,000 individuals in western Hudson Bay, a group of 1500 individuals in the eastern Hudson Bay arc, and a few i...

Individual specialization (IS), where individuals within populations irrespective of age, sex, and body size are either specialized or generalized in terms of resource use, has implications on ecological niches and food web structure. Niche size and degree of IS of near-top trophic-level marine predators have been little studied in polar regions or with latitude. We quantified the large-scale l...

Contaminants described as organochlorines (OCs; e.g., polychlorinated biphenyls [PCBs]) are present in tissues of marine mammals, including beluga whales (Delphinapterus leucas), but the complexity of contaminant exposure often is not fully known. The PCBs, OC pesticides, polybrominated diphenyl ether (PBDE) flame retardants, methylsulfonyl (MeSO2)- and hydroxy (OH)-PCB metabolites, and OH-PBDE...

This paper aims to analyze the physiological, perceptual, and behavioral adaptations in the Beluga Whale (Delphinapterus leucas) as a result of its arctic niche. The social implications of these adaptations will be examined by looking at each part as influential elements of each other. Lastly, the idea of defining culture in cetaceans will be addressed, including a proposal for examining cultur...

lactic acid bacteria are characterized as gram-positive, usually non-motile, non-sporulating bacteria that produce lactic acid as a major or sole product of their fermentative metabolism. in this study, the presence of lactobacilli were investigated in the intestines of beluga ( huso huso) and persian sturgeon ( acipenser persicus ), inhabiting caspian sea. the obtained data showed that various...

Masked tonal thresholds were measured for a beluga whale at one noise level and 32 frequencies between 40 Hz and 115 kHz. Critical ratios were estimated and compared with those previously measured for the bottlenose dolphin. Beluga whale critical ratios were found to be about 3 dB lower than those of the bottlenose dolphin. Absolute tonal thresholds were extended below previous measurements to ...

A population of approximately 650 beluga (Delphinapterus leucas) inhabits a short segment of the St. Lawrence estuary (SLE). Over 17 years (1983-1999), we have examined 129 (or 49%) of 263 SLE beluga carcasses reported stranded. The major primary causes of death were respiratory and gastrointestinal infections with metazoan parasites (22%), cancer (18%), and bacterial, viral, and protozoan infe...