Modelling the Changing Availability of Landfast Sea Ice Suitable for Breeding Ringed Seals Along the Coast of Labrador
Ringed seals are a key species in ice-covered Arctic marine ecosystems because they link the aquatic food web to higher level predators. In addition, this species is culturally important and is an important food source for northern Inuit communities. Ringed seals construct a well-sheltered birth lair under snow drifts created by rough sea ice to protect the pup from the cold and predators. As the quantity and quality of sea ice decreases due to climate change the availability of birthing habitat will decrease and pup survival in some areas of the seal's range will decrease as well. Loss of habitat that is essential to the species is an international concern that has led the United States to consider listing ringed seals as a threatened in a significant portion of their range.
This project will use archived satellite imagery to identify climate related changes in the availability of quality pupping habitat for ringed seals in coastal Labrador. This will allow researchers to link the reproductive productivity of seals to changing habitat, and gain a better understanding of the capacity of the species to adapt.
Results: Researchers used a sea ice habitat model to identify the presence of key ice features necessary for ringed seal pupping habitat in the regions of Nain, Hopedale, Lake Melville, and eastern Hudson Bay. Conditions along the coast of Labrador were challenging for pup survival for four years within the period from 2001 to 2007, Lake Melville experienced the least extreme variability among the region. During the course of this study, researchers were able to observe the ice dynamics that created the key ice features characteristic of good pupping habitats, such as sequential freezing that allows sheets of ice to bump and crack into one another forming large ridges of deformed ice. Other events, such as pack ice surges that compress useable rough ice habitat and rapid freezing that creates smooth ice, reduce the availability of suitable pupping habitat.
Further study is required to improve the sea-ice model in order to incorporate snow depth and to differentiate between snowdrifts (which are unsuitable for pupping) and some rough ice features that are useable habitat. Researchers are also conducting further study to model larger areas in the study regions listed above. Results from this study will be included in a scientific publication.
Atlantic: Newfoundland, Labrador Shelves
Fisheries and Oceans Canada
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