Health Assessment of Weddell Seals, \u3ci\u3eLeptonychotes weddellii\u3c/i\u3e, in McMurdo Sound, Antarctica

The demography of Weddell seals in eastern McMurdo Sound, Antarctica, has been well studied during the past three decades (e.g. Stirling 1971; Siniff et al. 1977; Testa and Siniff 1987; Hastings and Testa 1998; Gelatt et al. 2001). Detailed life-history data are available on thousands of seals tagged as pups in McMurdo Sound, making this population a rich resource for wildlife health studies because health parameters can be evaluated in the light of reproductive histories and genetic relationships of several generations of tagged seals. Recently, evidence of exposure to diseases generally associated with domestic animals and feral wildlife has been detected in Antarctic wildlife (Austin and Webster 1993; Olsen et al. 1996; Gardner et al. 1997; Retamal et al. 2000; Foster et al. 2002) and this has generated concern and debate regarding the risks of disease introduction to Antarctic wildlife. Antibodies to viruses that have caused large die-offs in phocids in other areas of the world have been detected in Weddell seals (Bengtson et al. 1991), and there is a historical report of a mass die-off of crabeater seals that may have had a viral etiology (Laws and Taylor 1957)

Diet of endangered Steller sea lions in the Aleutian Islands: New insights from DNA detections and bio-energetic reconstructions.

The endangered western stock of Steller sea lion (Eumetopias jubatus (Schreber, 1776)) still declines in the western Aleutian Islands and accurate diet information is vital to test leading hypotheses. We undertook the first bio-energetic diet reconstruction using both molecular and hard part prey identifications from >600 scats collected in March-April 2008 and 2012. Atka mackerel (Pleurogrammus monopterygius (Pallas, 1810)) remained a primary prey (17-27% by energy), but large (mean 60 cm) Pacific cod (Gadus macrocephalus (Tilesius, 1810)) also emerged as important prey (20-24%) in a more diverse diet than previously reported, with Cottidae and smooth lumpsucker (Aptocyclus ventricosus (Pallas, 1769)) also contributing ~10%. DNA detections highlighted a potentially important and previously underestimated prey, giant Pacific octopus ((Enteroctopus dofleini (W端lker, 1910)) (diet contribution 2-15% - dependent on prey size assumptions). While 504 unique DNA identifications resulted in significant increases for cephalopods, Pacific cod and smooth lumpsucker, hard part alone species rankings were similar to composite ones and bio-energetic species rankings similar to occurrence-based ones. Retention/regurgitation of large cephalopod beaks, the removal of large cod heads and skeletal fragility of lumpsuckers may explain these differences. DNA identifications provide valuable comparative and complementary prey occurrence data for pinnipeds, but composite diet estimates are optimal.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author