Spawning of Kattegat cod (Gadus morhua)-Mapping spatial distribution by egg surveys

Abstract

The Kattegat cod has been heavily depleted and is classified as exhibiting reduced reproductive capacity. There is therefore a need for updated information on cod spawning activity and specific locations of spawning grounds in the area. To address this, data from dedicated egg surveys in the Kattegat between 2004 and 2006 were analysed. Positively identified cod eggs confirmed that cod were spawning in the area during the period. The estimated daily egg production was highest in the southeastern part of the surveyed area (similar to 20 eggs m(-2) d(-1)) close to the entrance of the Sound and off the Swedish coast. North of latitude 56 degrees 45' N the daily egg production was low (0-5 eggs m(-2) d(-1)). The predicted distribution of daily egg production was broadly consistent with the two major spawning areas proposed by Vitale et al. (2008), although shifted southwards emphasizing the importance of the southernmost spawning area closer to the Sound. These results provide a baseline for future studies of spawning and life history characteristics of Kattegat cod, and also in studies designed to disentangle the stock complex in the Kattegat-Sound-Belt area. (C) 2013 Elsevier B.V. All rights reserved.

Keywords

Egg density; Ichthyoplankton; Spawning ground; Stock structure; TaqMan

Published in

Fisheries Research
2013, volume: 147, pages: 63-71
Publisher: ELSEVIER SCIENCE BV

SLU Authors

• Börjesson, Patrik

• Jonsson, Patrik

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

• Svedäng, Henrik

  • Department of Aquatic Resources (SLU Aqua), Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Fish and Aquacultural Science
Ecology

Publication identifier

• DOI: https://doi.org/10.1016/j.fishres.2013.04.012

Permanent link to this page (URI)

https://res.slu.se/id/publ/54905