{"id":373,"date":"2015-09-29T14:49:12","date_gmt":"2015-09-29T12:49:12","guid":{"rendered":"https:\/\/arctos.uit.no\/?p=373"},"modified":"2015-10-29T14:53:49","modified_gmt":"2015-10-29T12:53:49","slug":"373","status":"publish","type":"post","link":"https:\/\/arctos.uit.no\/?p=373","title":{"rendered":"New ARCTOS PhD: Virginie Ramasco"},"content":{"rendered":"

On Thursday 24th of September, Virginie Ramasco successfully defended her thesis entitled: ‘Spatial and temporal patterns of foraging of harbour seals (Phoca vitulina<\/em>) in Porsangerfjord’.<\/p>\n

This population of harbour seals has been hypothesised to act as a predator-pit for the cod stock in the area which has drastically declined in the 80’s and never fully recovered since. In her thesis Virginie investigated the foraging behaviour of theses seals in order to understand their role in the Porsangerfjord. As one major result she described two types of resting behaviour at sea, prolonged stays at the surface but also so called resting dives. This particular behaviour was documented for the first time for this species. Virginie also compared the identified foraging locations with the availability of potential prey. The results suggested that habour seals in Porsangerfjord have a preference for fish <25cm aggregated close to the haulout areas. Small codfish was preferred during autumn, but when getting less available due to overwintering in cold deep waters, seals would prefer small pelagic fish. Ice-formation making the pelagic fish less available however would provoke shifting back to small codfish. Ice-melt in late spring would reserve that trend again and seals would shift back to pelagic fish as preferred prey. Virginie therefore suggests that the impact of harbour seals on the cod population of Porsangerfjord changes across seasons and is lowered by the availability of highly aggregated pelagic fish during winter and spring<\/p>\n

\"OLYMPUS<\/a>

Photos: Ingjerd Nilsen<\/p><\/div>\n

Virginie’s thesis consists of three papers:<\/p>\n