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PARENT SESSION

PW10 Bioaccumulation and Biomagnification
Exhibit Hall
8:00 AM - Wednesday

(PW184) Organochlorine accumulation in odontocete melon tissue.

Gardner, S1, Pier, M2, Ylitalo, G3, Varanasi, U3, 1 Centro de Investigaciones Biologicas del Noroeste, La Paz, BCS, Mexico2 Amigos para la Conservacion de Cabo Pulmo, Los Barriles, BCS, Mexico3 Northwest Fisheries Science Center, NOAA, Seattle, WA, USA

ABSTRACT- Despite the importance of odontocete melon for performing ecolocation functions, little information is available on the accumulation of contaminants in this tissue and its effect on sound production. Previous studies have indicated that biosynthesis of acoustical lipids is largely independent of fluctuations in the fatty acid content of the diet and may occur in situ in the head tissue. This would suggest that once deposited, contaminants may be permanently stored in melon because of resistance to hydrolysis. Therefore this study was designed to determine the deposition and metabolism of lipid soluble contaminants in melon to better understand the ontology and function of acoustic tissues. Analyses of organochlorine residues in melon and blubber samples from porpoises (Phocoena sp.) and dolphin (Tursiops truncatus) were conducted from specimens available as incidental catch. Mean sum of OC concentrations in blubber as compared to melon tissue were not significantly different in adult or fetal porpoises. Principal Components Analysis (PCA) demonstrated that melon and blubber samples did not separate out and in many cases, melon and blubber tissue samples from the same individual had very similar scores. Total OC concentration in melon and blubber was significantly correlated to body length indicating that both maternal transfer in utero as well as bioaccumulation with growth of the odontocete determine concentrations of OCs in melon and blubber. These findings demonstrate that melon and blubber did not differ significantly in their contaminant burdens suggesting that a mechanism exists whereby these lipids are metabolized in the melon tissues.

Key words: odontocete, organochlorine, melon, marine mammal


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