Lipid content of blubber biopsies is not representative of blubber in situ for fin whales (Balaenoptera physalus)

摘要

Biopsy darting of free ranging cetaceans is a nonlethal tissue sampling technique where retrievable darts are delivered using a crossbow or modied rie (Lambertsen 1987). Biopsies permit various analyses of free-ranging cetaceans using a suite of techniques including molecular genetics, fatty acid (diet composition and ageing), immunohistochemical, stable isotope and persistent pollutant analyses (Baker et al. 1990, Borobia et al. 1995, Gauthier et al. 1997a, Todd et al. 1997, Hooker et al. 2008, Herman et al. 2009). The ndings from such studies have revolutionized our understanding of cetaceans (Borobia et al. 1995, Palsbll et al. 1997, Moller ¨ et al. 2001). This sampling method has been validated for analysis of persistent organochlorine contaminants in the blubber of some species of mysticetes (Gauthier et al. 1997b). Blubber lipid-content and thickness are of particular importance in the assessment of the life cycle status and health of cetaceans, particularly those capital breeders such as mysticetes where blubber lipid stores govern reproductive success (Pettis et al. 2004, Iverson 2008). Lipid content of n whale blubber for example, has been shown to vary with sex and reproductive status (Lockyer et al. 1985). One of the untested assumptions of the remote biopsy technique is that the lipid content of blubber biopsies is representative of that in situ, i.e., that there is no sampling effect. However Krahn et al. (2007) found surprising differences within the same region and season in percentage lipid content of blubber samples between live (biopsied) and stranded (excised) whales for both killer (Orcinus orca) and beluga (Delphinapterus leucas) whales.