Estimating the number of walruses in Svalbard from aerial surveys and behavioural data from satellite telemetry

ABSTRACT. All known terrestrial haul-out sites for walruses in Svalbard (n = 79) were surveyed during the period 1–3 August 2006, and sites that were in use (n = 17) were documented using digital photography. A total of 657 walruses were counted on land in the resultant images. An extensive behavioural data set from walruses equipped with satellite relay data loggers, covering August 2002 to August 2005, was used to account for walruses that were in the water. The proportion of walruses at sea during the survey was calculated to be 0.750 on the basis of 28 thirty-day periods from 23 male walruses. Time of day and wind chill did not significantly affect haul-out behaviour. However, a logistic regression model revealed both a correlation among haul-out patterns of individuals within years, and a year effect (χ2 = 6.42, df = 2, p = 0.04). Because the survey was not flown in a year when satellite tags were deployed, the interannual variance was retained in a model (with no other explanatory variables). The over-dispersion parameter from this model was 2.02 (deviance = 28.33, df = 14). Thus, variance in proportions of time individuals spent at sea was multiplied by this parameter to achieve a corrected SE around the estimate. The 95 % CI based on this SE corresponded to a proportion of walruses at sea during the survey between 0.717 and 0.781, resulting in an estimated total number of walruse

Bacterial diversity in faeces from polar bear (Ursus maritimus) in Arctic Svalbard

<p>Abstract</p> <p>Background</p> <p>Polar bears (<it>Ursus maritimus</it>) are major predators in the Arctic marine ecosystem, feeding mainly on seals, and living closely associated with sea ice. Little is known of their gut microbial ecology and the main purpose of this study was to investigate the microbial diversity in faeces of polar bears in Svalbard, Norway (74-81°N, 10-33°E). In addition the level of <it>bla</it>_TEMalleles, encoding ampicillin resistance (amp^r) were determined. In total, ten samples were collected from ten individual bears, rectum swabs from five individuals in 2004 and faeces samples from five individuals in 2006.</p> <p>Results</p> <p>A 16S rRNA gene clone library was constructed, and all sequences obtained from 161 clones showed affiliation with the phylum <it>Firmicutes</it>, with 160 sequences identified as <it>Clostridiales </it>and one sequence identified as unclassified <it>Firmicutes</it>. The majority of the sequences (70%) were affiliated with the genus <it>Clostridium</it>. Aerobic heterotrophic cell counts on chocolate agar ranged between 5.0 × 10⁴to 1.6 × 10⁶colony forming units (cfu)/ml for the rectum swabs and 4.0 × 10³to 1.0 × 10⁵cfu/g for the faeces samples. The proportion of amp^rbacteria ranged from 0% to 44%. All of 144 randomly selected amp^risolates tested positive for enzymatic β-lactamase activity. Three % of the amp^risolates from the rectal samples yielded positive results when screened for the presence of <it>bla</it>_TEMgenes by PCR. <it>Bla</it>_TEMalleles were also detected by PCR in two out of three total faecal DNA samples from polar bears.</p> <p>Conclusion</p> <p>The bacterial diversity in faeces from polar bears in their natural environment in Svalbard is low compared to other animal species, with all obtained clones affiliating to <it>Firmicutes</it>. Furthermore, only low levels of <it>bla</it>_TEMalleles were detected in contrast to their increasing prevalence in some clinical and commensal bacterial populations.</p