Blar i Brage IMR på forfatter "Kjesbu, Olav Sigurd"
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Skipped spawning in Northeast Arctic haddock Melanogrammus aeglefinus
Skjæraasen, Jon Egil; Korsbrekke, Knut; Nilsen, Trygve; Fonn, Merete; Kjesbu, Olav Sigurd; Dingsør, Gjert Endre; Nash, Richard David Marriott (Journal article; Peer reviewed, 2015-04-22) -
Some characteristics of sperm motility in European hake (Merluccius merluccius, L., 1758)
Groison, A.-L.; Fauvel, C.; Suquet, M.; Kjesbu, Olav Sigurd; Le Coz, J.R.; Mayer, Ian; Cosson, J. (Journal article; Peer reviewed, 2010-09-17)The objective of this paper is to characterize some of the sperm motility parameters in European hake (Merluccius merluccius), which is considered to be a species with aquaculture potential. The total ATP, ADP and AMP ... -
Some like it cold – Consequence of warming seas for the distribution of large bodied fish
Höffle, Hannes; Kjesbu, Olav Sigurd (ICES CM documents;2014/M:07, Conference object, 2014-09-15) -
Spawner quality effects on two measures of reproductive potential: have we been counting our eggs before they've hatched?
Marshall, C. Tara; Kjesbu, Olav Sigurd; Thorsen, Anders; Solemdal, Per (ICES CM documents, Working paper, 1999)Recent studies have found positive associations between recruitment and indices of spawner quality (condition) for stocks exhibiting an indeterminate relationship between recruitment and spawner biomass. This suggests ... -
Stereological calibration of the profile method to quickly estimate atresia levels in fish
Kjesbu, Olav Sigurd; Fonn, Merete; Gonzáles, Barbara Dunia; Nilsen, Trygve (Journal article; Peer reviewed, 2010-05)The (physical) ‘disector method’, a frequently cited stereological technique, has so far received little attention within fish fecundity studies, although it can be used to provide unbiased, assumption-free data on levels ... -
Stereological calibration of the profile method to quickly estimate atresia levels in fish
Kjesbu, Olav Sigurd; Fonn, Merete; Gonzáles, Barbara Dunia; Nilsen, Trygve (Journal article; Peer reviewed, 2010-05)The (physical) ‘disector method’, a frequently cited stereological technique, has so far received little attention within fish fecundity studies, although it can be used to provide unbiased, assumption-free data on levels ... -
Synergies between climate and management for Atlantic cod fisheries at high latitudes
Kjesbu, Olav Sigurd; Bogstad, Bjarte; Devine, Jennifer A.; Gjøsæter, Harald; Howell, Daniel; Ingvaldsen, Randi; Nash, Richard D.M.; Skjæraasen, Jon Egil (Journal article; Peer reviewed, 2014-02-18)The widespread depletion of commercially exploited marine living resources is often seen as a general failure of management and results in criticism of contemporary management procedures. When populations show dramatic and ... -
Systematic bias in estimates of reproductive potential of an Atlantic cod (Gadus morhua) stock: implications for stock–recruit theory and management
Marshall, C. Tara; Needle, Coby L.; Thorsen, Anders; Kjesbu, Olav Sigurd; Yaragina, Natalia A. (Journal article; Peer reviewed, 2006)Stock–recruit relationships that use spawning stock biomass (SSB) to represent reproductive potential assume that the proportion of SSB composed of females and the relative fecundity (number of eggs produced per unit ... -
Systematic bias in estimates of reproductive potential of cod stocks: implications for stock/recruit theory and management
Marshall, C. Tara; Needle, Coby L.; Thorsen, Anders; Kjesbu, Olav Sigurd; Yaragina, Natalia A. (ICES CM documents, Working paper, 2005)Stock/recruit relationships, describing the relationship between the parental population and the number of offspring produced, are a central tool in population ecology. For fish populations the stock/recruit relationship ... -
The effects of maternal status of Arcto-Norwegian cod on egg quality and vitality of early larvae. 1. The collection and characteristics of the cod females, a pilot study
Solemdal, Per; Kjesbu, Olav Sigurd; Kjørsvik, Elin (ICES CM Documents;1992/G:78, Working paper, 1992)On the basis of a new field method to determine the stage of spawning, egg groups from Arcto-Norwegian cod females in different stage of spawning were selected for further studies on egg quality and vitality of early ... -
The effects of maternal status of Arcto-Norwegian cod on egg quality and vitality of early larvae. 2. Preliminary results of the experiment in 1992
Solemdal, Per; Bergh, Øivind; Finn, Roderick Nigel; Fyhn, Hans Jørgen; Grahl-Nielsen, Otto; Homme, O.; Kjesbu, Olav Sigurd; Kjørsvik, Elin; Opstad, Ingegjerd; Skiftesvik, Anne Berit (ICES CM Documents;1992/G:79, Working paper, 1992)The stage of spawning of females of the Arcto-Norwegian cod caught during peak spawning in Lofoten had a profound effect on several vital parameters of the eggs and larvae. Significant negative correlations were ... -
The legacy of Johan Hjort: Challenges and critical periods ‒ past, present and future
Kjesbu, Olav Sigurd; Hubbard, Jennifer; Suthers, Iain M.; Schwach, Vera (Peer reviewed; Journal article, 2020)The 150th anniversary of Johan Hjort’s birth was celebrated by a symposium held in Bergen on 12–14 June 2019 to take a broad perspective on the origins of, and developments in, fisheries science and thereby examine current ... -
The North Atlantic spring-bloom system - where the changing climate meets the winter dark
Sundby, Svein; Drinkwater, Ken; Kjesbu, Olav Sigurd (Journal article; Peer reviewed, 2016-03-15)The North Atlantic with its spring-bloom ecosystem has its particular responses to climate change, many of them different from the other parts of the world's oceans. The system is strongly influenced by anthropogenic climate ... -
Thermal dynamics of ovarian maturation in Atlantic cod (Gadus Morhua)
Kjesbu, Olav Sigurd; Righton, David; Krüger-Johnsen, Maria; Thorsen, Anders; Michalsen, Kathrine; Fonn, Merete; Witthames, Peter R. (Journal article; Peer reviewed, 2010-03)The timing and success of spawning in marine fish are of fundamental importance to population persistence and distribution and, for commercial species, sustainability. Their physiological processes of reproduction are ... -
Timecourse of oocyte development in saithe Pollachius virens
Skjæraasen, Jon Egil; Devine, Jennifer Ann; Godiksen, Jane Aanestad; Fonn, Merete; Otterå, Håkon Magne; Kjesbu, Olav Sigurd; Norberg, Birgitta; Langangen, Øystein; Karlsen, Ørjan (Journal article; Peer reviewed, 2017)Wild caught North Sea saithe Pollachius virens were monitored for growth, sex steroid profiles and oocyte development pre-spawning and measured for egg size and group fecundity during the spawning season in the laboratory. ... -
Timing and determination of potential fecundity in Atlantic cod (Gadus morhua)
Skjæraasen, Jon Egil; Nilsen, Trygve; Kjesbu, Olav Sigurd (Journal article; Peer reviewed, 2005)Studies using annual averages of lipid storage or estimated quality of the feeding season have shown that energy reserves influence egg production in Atlantic cod (Gadus morhua). However, vitellogenesis starts months ... -
Tracking oocyte development and the timing of skipped spawning for north-east Arctic haddock (Melanogrammus aeglefinus)
Tronbøl, Frida; Johannesen, Edda; Alix, Maud; dos Santos Schmidt, Thassya Christina; Charitonidou, Katerina; Folkvord, Arild; Kjesbu, Olav Sigurd (Peer reviewed; Journal article, 2022)The present study tracked oocyte development over 9 months and noted incidences of ‘skipping’, i.e., adults terminating their upcoming reproductive cycle, in field-caught north-east Arctic (NEA) haddock (Melanogrammus ... -
Utvalg til å vurdere fremtidig utvikling i våre mest sentrale fiskebestander
Huse, Geir; Kjesbu, Olav Sigurd; Gjøsæter, Harald; Bogstad, Bjarte; Stenevik, Erling Kåre; Holst, Jens Christian; Fossum, Petter; Ingvaldsen, Randi; Johansen, Geir Odd; Skern-Mauritzen, Mette (Rapport fra Havforskningen;Nr. 29 - 2012, Working paper, 2012)