English
norskBlar i forfatter "Rikardsen, Audun"
Viser treff 1-6 av 6
-
Foraging movements of humpback whales relate to the lateral and vertical distribution of capelin in the Barents Sea
(Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-24)Understanding how individual animals modulate their behaviour and movement patterns in response to environmental variability plays a central role in behavioural ecology. Marine mammal tracking studies typically use physical environmental characteristics that vary, and/or proxies of prey distribution, to explain predator movements. Studies linking predator movements and the actual distributions ... -
Konflikter mellom ærfugl og blåskjelldyrking
(Research report; Forskningsrapport, 2006-01)Oppdrett av blåskjell har i de senere år økt sterkt i omfang i Norge, men kunnskapen om de økologiske konsekvensene av virksomheten er meget begrenset. Et betydelig problem som har oppstått i denne forbindelse er predasjon fra fugl, og da særlig ærfugl. Dette har klare negative konsekvenser for lønnsomheten, samt representerer et kunstig habitat og mulige negative påvirkninger for fugl. Bedre ... -
Mass strandings of seven toothed and baleen whale species in Northern Norway in March 2020 call for further investigation
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-06)Monitoring whale strandings are a key aspect of ecosystem management as stranded animals can provide indications on ecosystem health, pollution and adverse efects due to anthropogenic activities. Most mass mortality events are reported for toothed whales and rarely involve baleen whales. In the course of one month in spring 2020, 17 whales belonging to seven diferent species, stranded on the ... -
Round-trip migration and energy budget of a breeding female humpback whale in the Northeast Atlantic
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-05-27)In the northern hemisphere, humpback whales (<i>Megaptera novaeangliae</i>) typically migrate between summer/autumn feeding grounds at high latitudes, and specific winter/spring breeding grounds at low latitudes. Northeast Atlantic (NEA) humpback whales for instance forage in the Barents Sea and breed either in the West Indies, or the Cape Verde Islands, undertaking the longest recorded mammalian ... -
Røye som langtidsvert og smittereservoar for Gyrodactylus salaris i Skibotnelva i Troms
(Research report; Forskningsrapport, 2005-03)Skibotnelva i Troms var lenge det eneste vassdraget i våre to nordligste fylker med infeksjon av fiskeparasitten Gyrodactylus salaris. Parasitten ble første gang påvist i 1979, og to rotenonbehandlinger i den lakseførende delen (i 1988 og 1995) har vært mislykkede. Di-rektoratet for naturforvaltning vurderer bygging av langtidssperre som et av flere aktuelle utryddingstiltak i Skibotnelva. Imidlertid ... -
Thermal habitat of adult Atlantic salmon Salmo salar in a warming ocean
(Journal article; Tidsskriftartikkel; Peer reviewed, 2019-10-29)The year‐round thermal habitat at sea for adult Atlantic salmon <i>Salmo salar</i> (<i>n</i> = 49) from northern Norway was investigated using archival tags over a 10 year study period. During their ocean feeding migration, the fish spent 90% of the time in waters with temperatures from 1.6–8.4°C. Daily mean temperatures ranged from −0.5 to 12.9°C, with daily temperature variation up to 9.6°C. Fish ...
