Show simple item record

dc.contributor.supervisor Ferguson, Steven H. (Biological Sciences) en
dc.contributor.author Vincent-Chambellant, Magaly
dc.date.accessioned 2010-09-10T23:01:18Z
dc.date.available 2010-09-10T23:01:18Z
dc.date.issued 2010-09-10T23:01:18Z
dc.identifier.uri http://hdl.handle.net/1993/4159
dc.description.abstract Recently, Hudson Bay experienced unidirectional trends in temperature, sea-ice extent, time of break-up, and length of the open-water season. Predicted impacts on population dynamics of ice-associated species include habitat loss and shift in prey availability. The ringed seal (Phoca hispida) depends on a stable ice platform with sufficient snow depth and a productive open-water season for reproduction and survival. Evidence of ringed seal sensitivity to environmental variations has been reported, but mechanisms involved were poorly understood. In western Hudson Bay, density, life-history traits, and diet of ringed seals were monitored over two decades, providing an opportunity to understand the effects of climatic variations on the population dynamics of this long-lived carnivore. Ringed seal density was estimated through strip-transect analyses after aerial surveys were flown in western Hudson Bay in late spring during the annual moult in the 1990s and 2000s. During these periods, ringed seals were also sampled from Inuit subsistence fall harvests In Arviat, NU, and ages, reproductive status, percentage of pups in the harvest, body condition, and diet were assessed. Strong inter-annual variations in these parameters were observed, and a decadal cycle was suggested and related to variations in the sea-ice regime. The cold and heavy ice conditions that prevailed in western Hudson Bay in 1991-92 likely induced a decrease in pelagic productivity, reducing the availability to ringed seals of sand lances (Ammodytes sp.), their major prey. The nutritional stress endured, combined with a strong predation pressure, led to a decrease in ringed seal reproductive performances, pup survival, and density during the 1990s. The recovery of ringed seal demographic parameters and number in the 2000s was associated with the immigration of pups, juveniles, and young adults into western Hudson Bay. Impact of current climatic trends on ringed seal population dynamics was not apparent, but considering the limited range of environmental variations tolerated by ringed seals, the response of this species to climate warming might be of a catastrophic type. Ringed seals were found to be good indicators of ecosystem changes, and long-term monitoring of the species in Hudson Bay should be a priority. en
dc.format.extent 3662877 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject density en
dc.subject distribution en
dc.subject life-history en
dc.subject body condition en
dc.subject reproduction en
dc.subject diet en
dc.subject spring ice break-up en
dc.subject temporal variation en
dc.subject snow depth en
dc.subject ice cover en
dc.subject climate change en
dc.title Ecology of ringed seals (Phoca hispida) in western Hudson Bay, Canada en
dc.degree.discipline Biological Sciences en
dc.contributor.examiningcommittee Roth, James (Biological Sciences) Stern, Gary (Environment and Geography) Kelly, Brendan Patrick (National Marine Mammal Laboratory, NOAA Alaska Fisheries Science Center, USA) en
dc.degree.level Doctor of Philosophy (Ph.D.) en
dc.description.note October 2010 en


Files in this item

This item appears in the following Collection(s)

Show simple item record

View Statistics