Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence
Correlations between catch rates in bottom-trawl surveys and indices of environmental conditions or fish distribution have been attributed to effects of the environmental conditions or fish distribution on catchability to the survey. We tested this hypothesis using data on cod in the southern Gulf o...
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fthighwire:oai:open-archive.highwire.org:icesjms:57/1/56 2023-05-15T15:27:44+02:00 Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence Swain, D. P. Poirier, G. A. Sinclair, A. F. 2000-02-01 00:00:00.0 text/html http://icesjms.oxfordjournals.org/cgi/content/short/57/1/56 https://doi.org/10.1006/jmsc.1999.0516 en eng Oxford University Press http://icesjms.oxfordjournals.org/cgi/content/short/57/1/56 http://dx.doi.org/10.1006/jmsc.1999.0516 Copyright (C) 2000, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer Articles TEXT 2000 fthighwire https://doi.org/10.1006/jmsc.1999.0516 2013-05-27T04:57:56Z Correlations between catch rates in bottom-trawl surveys and indices of environmental conditions or fish distribution have been attributed to effects of the environmental conditions or fish distribution on catchability to the survey. We tested this hypothesis using data on cod in the southern Gulf of St Lawrence. Survey catch rates of cod were significantly correlated with indices of bottom temperature and of cod temperature and depth distributions. Correlations were in the directions expected on the basis of predicted effects on catchability or availability to the survey. However, tests involving calibrations of sequential population analysis (SPA) or residuals from multiplicative analyses of the survey catch rates (with terms for yearclass, age and cumulative mortality) did not support the hypothesis that these correlations resulted from effects on catchability to the survey. These tests provided no support for an effect of cod temperature or depth distribution on catchability. They provided some support for an effect of bottom temperature conditions on availability to the survey, but this effect on availability was not reflected by the correlations observed between bottom temperature indices and survey catch rates. We conclude that adjustments for effects on catchability should be based on relationships with inconsistencies in survey catch rates instead of relationships with the catch rates themselves. These adjustments could be incorporated in calibration of the SPA or calculated based on relationships with residuals from models relating survey catch rate to yearclass, age and fishing mortality. However, such adjustments were negligible in the case of southern Gulf of St Lawrence cod. Text atlantic cod Gadus morhua HighWire Press (Stanford University) ICES Journal of Marine Science 57 1 56 68 |
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Articles Swain, D. P. Poirier, G. A. Sinclair, A. F. Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
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description |
Correlations between catch rates in bottom-trawl surveys and indices of environmental conditions or fish distribution have been attributed to effects of the environmental conditions or fish distribution on catchability to the survey. We tested this hypothesis using data on cod in the southern Gulf of St Lawrence. Survey catch rates of cod were significantly correlated with indices of bottom temperature and of cod temperature and depth distributions. Correlations were in the directions expected on the basis of predicted effects on catchability or availability to the survey. However, tests involving calibrations of sequential population analysis (SPA) or residuals from multiplicative analyses of the survey catch rates (with terms for yearclass, age and cumulative mortality) did not support the hypothesis that these correlations resulted from effects on catchability to the survey. These tests provided no support for an effect of cod temperature or depth distribution on catchability. They provided some support for an effect of bottom temperature conditions on availability to the survey, but this effect on availability was not reflected by the correlations observed between bottom temperature indices and survey catch rates. We conclude that adjustments for effects on catchability should be based on relationships with inconsistencies in survey catch rates instead of relationships with the catch rates themselves. These adjustments could be incorporated in calibration of the SPA or calculated based on relationships with residuals from models relating survey catch rate to yearclass, age and fishing mortality. However, such adjustments were negligible in the case of southern Gulf of St Lawrence cod. |
format |
Text |
author |
Swain, D. P. Poirier, G. A. Sinclair, A. F. |
author_facet |
Swain, D. P. Poirier, G. A. Sinclair, A. F. |
author_sort |
Swain, D. P. |
title |
Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
title_short |
Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
title_full |
Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
title_fullStr |
Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
title_full_unstemmed |
Effect of water temperature on catchability of Atlantic cod (Gadus morhua) to the bottom-trawl survey in the southern Gulf of St Lawrence |
title_sort |
effect of water temperature on catchability of atlantic cod (gadus morhua) to the bottom-trawl survey in the southern gulf of st lawrence |
publisher |
Oxford University Press |
publishDate |
2000 |
url |
http://icesjms.oxfordjournals.org/cgi/content/short/57/1/56 https://doi.org/10.1006/jmsc.1999.0516 |
genre |
atlantic cod Gadus morhua |
genre_facet |
atlantic cod Gadus morhua |
op_relation |
http://icesjms.oxfordjournals.org/cgi/content/short/57/1/56 http://dx.doi.org/10.1006/jmsc.1999.0516 |
op_rights |
Copyright (C) 2000, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer |
op_doi |
https://doi.org/10.1006/jmsc.1999.0516 |
container_title |
ICES Journal of Marine Science |
container_volume |
57 |
container_issue |
1 |
container_start_page |
56 |
op_container_end_page |
68 |
_version_ |
1766358142336106496 |