Blar i Published in cooperation with others på forfatter "Ottersen, Geir"
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Ambient temperature and distribution of northeast arctic cod
Ottersen, Geir; Michalsen, Kathrine; Nakken, Odd (ICES CM documents, Working paper, 1996)Most studies on the effects of field temperature on fish distribution and population parameters have considered the temperature and its variability at fixed stations or sections rather than the temperature in the actual ... -
Climatic effects filtered through the food web affect the dynamics of Arcto-Norwegian cod
Hjermann, Dag Ø.; Eikeset, Anne Maria; Bogstad, Bjarte; Ottersen, Geir; Stenseth, Nils Christian (ICES CM documents, Working paper, 2005)The world's largest cod stock, the Arcto-Norwegian cod (a.k.a. North-East Arctic cod), is heavily influenced by temperature in two ways: First, cod recruitment tends to be high when Barents Sea temperature in the spawning ... -
Combining hydrographical particles-tracking models with spatial analyses to evaluate spatial dynamics of cod larvae and 0-group in the Barents Sea
Hidalgo, Manuel; Gusdal, Yvonne; Dingsør, Gjert Endre; Ciannelli, Lorenzo; Hjermann, Dag Ø.; Ottersen, Geir; Stige, Leif Christian; Fossum, Ingerid; Melsom, Arne; Stenseth, Nils Christian (ICES CM Documents;2009/C:06, Working paper, 2009)Recruitment ecology of cod has been an important focus within the framework of GLOBEC. A large part of this work focused on understanding the spatiotemporal component of cod populations. For the early pelagic life stages, ... -
Current patterns during pelagic stages determine interannual variability in length-at-age of juvenile Arcto-Norwegian cod
Ottersen, Geir; Helle, Kristin; Bogstad, Bjarte (ICES CM documents, Working paper, 2001) -
Dramatic changes in spawning stock age-structure of Barents Sea cod
Ottersen, Geir; Hjermann, Dag Ø.; Stenseth, Nils Christian (ICES CM documents, Working paper, 2004)Atlantic Cod (Gadus morhua) is one of the commercially most important fish species in the North Atlantic and plays a central role in several ecosystems. Fishing pressure has been heavy over a prolonged period and the ... -
Enhancing stock-recruitment models for North Sea cod by including climate and zooplankton
Ottersen, Geir; Olsen, Esben Moland; Stenseth, Nils Christian (ICES CM documents;2009/C:08, Working paper, 2009)The “recruitment problem” - trying to understand what regulates recruitment variability in marine fish populations - has been the number one issue in fisheries science since the early twentieth century. Intuitively, the ... -
An evaluation of recruitment indices for Northeast Arctic cod (Gadus morhua L.)
Helle, Kristin; Bogstad, Bjarte; Marshall, C. Tara; Michalsen, Kathrine; Ottersen, Geir; Pennington, Michael (ICES CM documents, Working paper, 1999)Indices of the abundance of Northeast Arctic cod (Gadus morhua L.) for various life stages were compared in order to determine the earliest stage at .which year-class strength is established. The indices considered are: ... -
Growth of northeast arctic cod in relation to ambient temperature
Michalsen, Kathrine; Ottersen, Geir; Nakken, Odd (ICES CM documents, Working paper, 1996)In the present study temperature related changes in horizontal distribution are described and the influence of temperature on the growth of Northeast Arctic cod is interpreted. Data from acoustic-and bottom trawl surveys ... -
IMR status report on the Barents Sea Ecosystem, 2004-2005
Stiansen, Jan Erik; Bogstad, Bjarte; Dalpadado, Padmini; Gjøsæter, Harald; Hauge, Kjellrun Hiis; Ingvaldsen, Randi; Loeng, Harald; Mauritzen, Mette; Mehl, Sigbjørn; Ottersen, Geir; Stenevik, Erling Kåre (Working paper, 2005) -
Including climate into the assessment of future fish recruitment, using multiple regression models.
Stiansen, Jan Erik; Aglen, Asgeir; Bogstad, Bjarte; Loeng, Harald; Mehl, Sigbjørn; Nakken, Odd; Ottersen, Geir; Svendsen, Einar (ICES CM documents, Working paper, 2005)Climate variability has generally not been included in the assessment of fish stocks in the Barents Sea and Norwegian Sea. However, in recent years there has been a focus on implementing climate variability in the assessment ... -
Inter-regional comparison of climate effects on marine fish populations facilitated through classification of mechanisms
Ottersen, Geir; Stenseth, Nils Christian (ICES CM documents;2007/D:17, Working paper, 2007)Variations in climate strongly affect the structure and function of marine ecosystems, but a number of different mechanisms are at play and their relative importance varies between regions and with time. There are obvious ... -
Landscape dynamics and predator-prey interactions in marine environments
Ciannelli, Lorenzo; Bailey, Kevin; Frank, Kenneth T.; Hjermann, Dag Ø.; Ottersen, Geir; Stenseth, Nils Christian (ICES CM documents, Working paper, 2004)In several sub-arctic marine ecosystems of the North Atlantic capelin are the primary prey item for cod, and the trophic interaction between capelin and cod is a central energetic pathway. However, in the North Pacific ... -
Some environmental factors that influence the growth of Arcto-Norwegian cod from the early juvenile to the adult stage
Helle, Kristin; Bogstad, Bjarte; Ottersen, Geir; Pennington, Michael (ICES CM documents, Working paper, 2000)A high growth rate for Arcto-Norwegian cod (Gadus morhua L.) in the Barents Sea and adjacent areas from the larval stage to the 0-group stage enhances survival and ultimately recruitment to the fishery. However, it appears ... -
Spatial patterns of age-0 cod survival in the Barents Sea
Ciannelli, Lorenzo; Dingsør, Gjert Endre; Bogstad, Bjarte; Ottersen, Geir; Chan, Kung-Sik; Gjøsæter, Harald; Stenseth, Nils Christian (ICES CM documents, Working paper, 2005)Apart from human harvest, recruitment dynamics is conceivably recognized as the main source of population variability of marine fish stocks. Factors affecting recruitment dynamics can change over both temporal and spatial ... -
Statistical modelling of temperature variability in the Barents Sea
Ottersen, Geir; Ådlandsvik, Bjørn; Loeng, Harald (ICES CM Documents;1994/S:2, Working paper, 1994)During the latter years an effort has been made to find out more about the relations between environmental variation and recruitment, growth, distribution and migration of fish. The rationale has to a large degree been ... -
Trophic interactions affecting a key ecosystem component: a multi-stage analysis of the recruitment of the Barents Sea capelin
Hjermann, Dag Ø.; Bogstad, Bjarte; Dingsør, Gjert Endre; Gjøsæter, Harald; Ottersen, Geir; Eikeset, Anne Maria; Stenseth, Nils Christian (ICES CM documents;2009/ C:07, Working paper, 2009)