Northern cod re-establish historical migration patterns linked to capelin: insights from pop-up satellite archival tags
In May 2012–2015, 90 large (85–117 cm) Northern cod ( Gadus morhua) with pop-up satellite archival tags (PSATs) set to release 1 year later were released from offshore spawning aggregations on the northeast Newfoundland shelf. Forty-nine (54%) transmitted or were recovered; 82% migrated inshore and...
Published in: | Canadian Journal of Fisheries and Aquatic Sciences |
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Main Authors: | , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Canadian Science Publishing
2024
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Subjects: | |
Online Access: | http://dx.doi.org/10.1139/cjfas-2023-0172 https://cdnsciencepub.com/doi/full-xml/10.1139/cjfas-2023-0172 https://cdnsciencepub.com/doi/pdf/10.1139/cjfas-2023-0172 |
Summary: | In May 2012–2015, 90 large (85–117 cm) Northern cod ( Gadus morhua) with pop-up satellite archival tags (PSATs) set to release 1 year later were released from offshore spawning aggregations on the northeast Newfoundland shelf. Forty-nine (54%) transmitted or were recovered; 82% migrated inshore and 15% remained offshore (balance predated). Geo-locations were based on release, capture, and surfacing positions, and at tag-recorded depths <50 m, on Kalman-predicted light-based longitudes matched with coastal bathymetry. Migrating fish moved southwestward on average 5° longitude (350 km) and 2° latitude (222 km) to the northeast coast of Newfoundland, southern Labrador, and northern Grand Bank, as historically from similar release points. Migration onset through the Labrador Current (<0 °C) and arrival inshore were correlated with capelin ( Mallotus villosus) peak spawning, inshore duration with capelin, and cod biomass. Both species were delayed a month from historical norms. The probability of a cod remaining inshore after 1 December was 50%, which could impact time-dependent surveys. Fishing exploitation was 6% and predation 5%. Northern cod have re-established historical spatial migration patterns, with capelin a key influence on timing and duration inshore. |
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