The trophic niche (recent and time-integrated niche estimates) of polymorphic populations of Arctic charr was investigated in two lakes in Northern Norway. The lakes, Tårnvatn and Skøvatn, have three and two morphs, respectively. Since the two systems are very similar in environmental conditions and fish communities, comparable niches between similar trophic morphs across lakes were expected caused ...

The Seasonal population dynamics of the small copepod species Oithona similis (cyclopoida), Microsotella norvegica (harpacticoida) and Microcalanus spp. were investigated in the northern Norwegian fjords Balsfjord, Altafjord and Porsangerfjord. In this study a WP-2 net with 64 µm mesh size was used to sample all the stages of O. similis, M. norvegica and Microcalanus spp. Copepodite stages CI – CVI ...

Predator aversion is an important adaptation that can significantly lower the mortality rate among prey animals, but avoiding a predator requires knowing and recognizing them. The predator aversion of Common gulls and Mallard ducks at Prestvannet Lake, Tromsø, Northern Norway was tested in an experiment by placing differing objects resembling snakes next to bread during the summer and autumn of 2017. ...

The introduced red king crab (Paralithodes camtschaticus) has successfully established in Norwegian waters since its release to the Barents Sea in the 1960’s. It has become an important commercial resource contributing to the local coastal society in the eastern region of Finnmark. The fishery consists of one quota regulated area east of 26° (North Cape) and an open fishery west of 26°E. During the ...

Migrating reindeer and caribou tend to return to traditional calving locations every spring with specific environmental conditions and protection of calving grounds is a central part of Rangifer conservation. In contrast, the non-migratory Svalbard reindeer inhabit an environment free of predators during calving season making them ideal as a reference population. Little is known about habitat ...

Since 2011, large numbers of humpback whales have aggregated to feed on Norwegian spring-spawning herring overwintering from late October to February within the fjords of the Troms county in Northern Norway. Whale aggregations are new in this region and little information on the whales’ behaviour is available. How whales dive and forage and how they adjust to the extreme light regime at this latitude ...

The rapid growth of tourism in Polar Regions stimulates a need for investigating potential impacts on targeted species and sensitive areas, such as walrus (Odobenus rosmarus) haul-out sites. This study examines effects of tourist visitations on haul-out dynamics and site use by walruses in Svalbard, Norway. Camera stations were established at five traditional walrus haul-out sites that experience ...

Duration of parental care in avian species varies widely, from altricial to precocial species. The seabird family Alcidae is unique among birds in the variation of mass and age at nest departure. The common guillemot Uria aalge exhibits an intermediate nest departure, where chicks leave the nest flightless and only at a quarter of adult body size. The aim of this study was to examine factors controlling ...

Three different mark-recapture models were applied to resighting data for Brünnich's guillemot (Uria lomvia) chicks obtained from photo series. Performances of the various models as potential tools for estimating chick survival over the breeding season were assessed. Of particular interest was Pradel’s multievent model, estimating state transition probabilities while accounting for uncertainty of ...

I used a theoretical model with different predatory preference relationships but with no direct competition. Simulated time series were statistically analysed to evaluate changes in rodent dynamics, with respect to periodicity, synchrony, amplitude and symmetry. The study found that shared predation could mediate a relationship between the two rodents to some extent. Periodicity increased on average ...