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dc.contributor.authorSvedang, Hendrik
dc.contributor.authorBarth, Julia Maria Isis
dc.contributor.authorSvenson, Anders
dc.contributor.authorJonsson, Patrik
dc.contributor.authorJentoft, Sissel
dc.contributor.authorKnutsen, Halvor
dc.contributor.authorAndre, Carl
dc.date.accessioned2019-03-06T12:16:41Z
dc.date.available2019-03-06T12:16:41Z
dc.date.created2018-10-15T09:06:03Z
dc.date.issued2018
dc.identifier.issn1054-3139
dc.identifier.urihttp://hdl.handle.net/11250/2588992
dc.description.abstractDramatic and persistent reductions in Atlantic cod (Gadus morhua) are common in many coastal areas. While offshore cod stocks still were abundant and productive, the Swedish west coast showed signs of diminishing adult cod abundance at the beginning of the 1980s, where the local cod component was considered to be extirpated. To survey the present cod spawning activity and stock composition, we initiated egg trawling over two consecutive years (203 hauls in total) in combination with population genetic analyses (425 individually genotyped eggs). Here, we provide evidence of cod spawning at the Swedish Skagerrak coast, suggesting recolonization or that local cod has recovered from a nearly depleted state. Early stage eggs were found inside fjords too far to have been transported by oceanic drift from offshore spawning areas. The cod eggs were genetically similar in early to late life-stages and cluster mainly with the local adult cod, indicating that eggs and adults belong to the same genetic unit. The cod eggs were genetically differentiated from adult North Sea cod, and, to a lesser degree, also from the Kattegat and Öresund cod, i.e. indicating a possible recovery of local coastal stock. The patterns of the genetic structure in the inshore areas are, however, difficult to fully disentangle, as Atlantic cod in the North Sea-Skagerrak area seem to be a mixture of co-existing forms: local cod completing their entire life cycle in fjords and sheltered areas, and oceanic populations showing homing behaviours. The egg abundances are considerably lower compared with what is found in similar studies along the Norwegian Skagerrak coast. Nevertheless, the discovery of locally spawning cod along the Swedish west coast—although at low biomasses—is an encouraging finding that highlights the needs for endurance in protective measures and of detailed surveys to secure intraspecific biodiversity and ecosystem services.nb_NO
dc.language.isoengnb_NO
dc.titleLocal cod (Gadus morhua) revealed by egg surveys and population genetic analysis after longstanding depletion on the Swedish Skagerrak coastnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.description.versionpublishedVersionnb_NO
dc.source.journalICES Journal of Marine Sciencenb_NO
dc.identifier.doi10.1093/icesjms/fsy166
dc.identifier.cristin1620289
cristin.unitcode7431,0,0,0
cristin.unitnameHavforskningsinstituttet
cristin.ispublishedtrue
cristin.fulltextoriginal
cristin.qualitycode1


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