AB 5:133-142 (2009)  -  DOI: https://doi.org/10.3354/ab00144

Link between vertical and horizontal movement patterns of cod in the North Sea

Victoria J. Hobson1,2,*, David Righton2, Julian D. Metcalfe2, Graeme C. Hays1

1Institute of Environmental Sustainability, Swansea University, Singleton Park, Swansea SA2 8PP, UK
2Centre for Environment, Fisheries and Aquaculture Science, Lowestoft Laboratory, Pakefield Road, Lowestoft, Suffolk NR33 0HT, UK

ABSTRACT: We used a geolocation method based on tidal amplitude and water depth to assess the horizontal movements of 14 cod Gadus morhua equipped with time-depth recorders (TDR) in the North Sea and English Channel. Tracks ranged from 40 to 468 d and showed horizontal movements of up to 455 km and periods of continuous localised residence of up to 360 d. Cod spent time both in midwater (43% of total time) and near the seabed (57% of total time). A variety of common vertical movement patterns were seen within periods of both residence and directed horizontal movement. Hence particular patterns of vertical movement could not unequivocally define periods of migration or localised residence. After long horizontal movements, cod tended to adopt resident behaviour for several months and then return to broadly the same location where they were tagged, indicating a geospatial instinct. The results suggest that residence and homing behaviour are important features of Atlantic cod behaviour.


KEY WORDS: Groundfish · Horizontal movement · Geolocation · Vertical behaviour · Locational accuracy · Hidden Markov model


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Cite this article as: Hobson VJ, Righton D, Metcalfe JD, Hays GC (2009) Link between vertical and horizontal movement patterns of cod in the North Sea. Aquat Biol 5:133-142. https://doi.org/10.3354/ab00144

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