Blar i Research Programmes på forfatter "Kjesbu, Olav Sigurd"
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The fate of vitellogenic follicles in experimentally monitored Atlantic cod Gadus morhua (L.): Application to stock assessment
Witthames, Peter R.; Thorsen, Anders; Kjesbu, Olav Sigurd (Journal article; Peer reviewed, 2010-05)In this paper we report on the fate of vitellogenic follicles (VF) as either alpha atretic follicles (αF) or post-ovulatory follicles (POFs) using histology and captive Atlantic cod (Gadus morhua) in three experiments. In ... -
Long-term changes in the total egg production of Norwegian spring-spawning herring Clupea harengus (L.)—Implications of variations in population structure and condition factor
Ndjaula, Hilkka O.N.; Nash, Richard D.M.; Slotte, Aril; Johannessen, Arne; Kjesbu, Olav Sigurd (Journal article; Peer reviewed, 2010-05)The reproductive potential of Norwegian spring-spawning herring (Clupea harengus) was estimated in terms of total egg production (TEP) for the period 1935–2005, using a model where spawning stock numbers (SSN)-, weight- ... -
Mechanisms regulating oocyte recruitment and skippedspawning in Northeast Arctic cod (Gadus morhua L.)
Skjæraasen, Jon Egil; Kennedy, James; Thorsen, Anders; Fonn, Merete; Strand, Bente; Mayer, Ian; Kjesbu, Olav Sigurd (Journal article; Peer reviewed, 2009-09)To examine mechanisms that affect fecundity, atresia and skipped spawning in Northeast Arctic cod (Gadus morhua L.), we conducted an experiment where wild-caught cod (>60 cm) kept under restricted food regimes were subjected ... -
The reproductive cycle of female Ballan wrasse Labrus bergylta in high latitude, temperate waters
Muncaster, S.; Andersson, Eva; Kjesbu, Olav Sigurd; Taranger, Geir Lasse; Skiftesvik, Anne Berit; Norberg, Birgitta (Journal article; Peer reviewed, 2010-08)This 2 year study examined the reproductive cycle of wild female Ballan wrasse Labrus bergylta in western Norway as a precursor to captive breeding trials. Light microscopy of ovarian histology was used to stage gonad ... -
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 ...