Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia
Exploitation of Skeena River sockeye salmon has been conducted almost solely by drift gillnets since 1875. This study was designed to determine the selective properties of nylon gillnets presently in use; to compare these with properties of linen nets used prior to 1955; and, using statistics of cat...
Published in: | Journal of the Fisheries Research Board of Canada |
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Canadian Science Publishing
1971
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Online Access: | http://dx.doi.org/10.1139/f71-123 http://www.nrcresearchpress.com/doi/pdf/10.1139/f71-123 |
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crcansciencepubl:10.1139/f71-123 2023-12-17T10:48:47+01:00 Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia Todd, Ian St. P. Larkin, P. A. 1971 http://dx.doi.org/10.1139/f71-123 http://www.nrcresearchpress.com/doi/pdf/10.1139/f71-123 en eng Canadian Science Publishing http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining Journal of the Fisheries Research Board of Canada volume 28, issue 6, page 821-842 ISSN 0015-296X General Medicine journal-article 1971 crcansciencepubl https://doi.org/10.1139/f71-123 2023-11-19T13:39:28Z Exploitation of Skeena River sockeye salmon has been conducted almost solely by drift gillnets since 1875. This study was designed to determine the selective properties of nylon gillnets presently in use; to compare these with properties of linen nets used prior to 1955; and, using statistics of catch and escapement, to estimate the selective action of the fishery as a whole on sockeye and pink salmon in 1968.Unique selectivity curves for nylon nets of [Formula: see text] mesh size could not be determined from sockeye catches. Mean size of age class 1.2 sockeye increased with mesh size but mean size of the predominant age class 1.3 sockeye demonstrated no trend. Age class 1.3 sockeye were among the largest on record and were too large to gill properly in all mesh sizes used.Comparison of [Formula: see text] mesh nylon gillnet with linen nets of [Formula: see text] mesh used in the historic fishery was also influenced by the large size of age class 1.3 sockeye. Nylon nets were 2.5 and 2.7 times as efficient as linen for sockeye, and 8.0 and 9.0 times for pink salmon. Nylon gillnets caught larger sockeye and pink salmon than did linen. Variances of mean size were also greater for catches in nylon.The statistics of catch and escapement for 1968 indicated that selection increased over the length range of age 1.2 sockeye but decreased over the length range of age class 1.3 sockeye. For pink salmon, which were extremely small in 1968, selection was increasingly large for larger size males and females. The length–girth relations of the species and sexes accounted for most of the difference between the selectivity curves. Retention by gillnets declined once the girth/mesh ratio exceeded 1.2 for sockeye. For pink salmon, no females were of a size to equal this ratio; the descending limb of the selectivity curve was due solely to males as the retention rates declined once girth/mesh ratio exceeded 1.0.These findings suggest that in most years the gillnet fishery on the Skeena River would tend to select relatively larger ... Article in Journal/Newspaper Pink salmon Canadian Science Publishing (via Crossref) Sockeye ENVELOPE(-130.143,-130.143,54.160,54.160) Skeena ENVELOPE(-130.198,-130.198,53.646,53.646) Skeena River ENVELOPE(-130.113,-130.113,54.015,54.015) Journal of the Fisheries Research Board of Canada 28 6 821 842 |
institution |
Open Polar |
collection |
Canadian Science Publishing (via Crossref) |
op_collection_id |
crcansciencepubl |
language |
English |
topic |
General Medicine |
spellingShingle |
General Medicine Todd, Ian St. P. Larkin, P. A. Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
topic_facet |
General Medicine |
description |
Exploitation of Skeena River sockeye salmon has been conducted almost solely by drift gillnets since 1875. This study was designed to determine the selective properties of nylon gillnets presently in use; to compare these with properties of linen nets used prior to 1955; and, using statistics of catch and escapement, to estimate the selective action of the fishery as a whole on sockeye and pink salmon in 1968.Unique selectivity curves for nylon nets of [Formula: see text] mesh size could not be determined from sockeye catches. Mean size of age class 1.2 sockeye increased with mesh size but mean size of the predominant age class 1.3 sockeye demonstrated no trend. Age class 1.3 sockeye were among the largest on record and were too large to gill properly in all mesh sizes used.Comparison of [Formula: see text] mesh nylon gillnet with linen nets of [Formula: see text] mesh used in the historic fishery was also influenced by the large size of age class 1.3 sockeye. Nylon nets were 2.5 and 2.7 times as efficient as linen for sockeye, and 8.0 and 9.0 times for pink salmon. Nylon gillnets caught larger sockeye and pink salmon than did linen. Variances of mean size were also greater for catches in nylon.The statistics of catch and escapement for 1968 indicated that selection increased over the length range of age 1.2 sockeye but decreased over the length range of age class 1.3 sockeye. For pink salmon, which were extremely small in 1968, selection was increasingly large for larger size males and females. The length–girth relations of the species and sexes accounted for most of the difference between the selectivity curves. Retention by gillnets declined once the girth/mesh ratio exceeded 1.2 for sockeye. For pink salmon, no females were of a size to equal this ratio; the descending limb of the selectivity curve was due solely to males as the retention rates declined once girth/mesh ratio exceeded 1.0.These findings suggest that in most years the gillnet fishery on the Skeena River would tend to select relatively larger ... |
format |
Article in Journal/Newspaper |
author |
Todd, Ian St. P. Larkin, P. A. |
author_facet |
Todd, Ian St. P. Larkin, P. A. |
author_sort |
Todd, Ian St. P. |
title |
Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
title_short |
Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
title_full |
Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
title_fullStr |
Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
title_full_unstemmed |
Gillnet Selectivity on Sockeye ( Oncorhynchus nerka ) and Pink Salmon ( O . gorbuscha ) of the Skeena River System, British Columbia |
title_sort |
gillnet selectivity on sockeye ( oncorhynchus nerka ) and pink salmon ( o . gorbuscha ) of the skeena river system, british columbia |
publisher |
Canadian Science Publishing |
publishDate |
1971 |
url |
http://dx.doi.org/10.1139/f71-123 http://www.nrcresearchpress.com/doi/pdf/10.1139/f71-123 |
long_lat |
ENVELOPE(-130.143,-130.143,54.160,54.160) ENVELOPE(-130.198,-130.198,53.646,53.646) ENVELOPE(-130.113,-130.113,54.015,54.015) |
geographic |
Sockeye Skeena Skeena River |
geographic_facet |
Sockeye Skeena Skeena River |
genre |
Pink salmon |
genre_facet |
Pink salmon |
op_source |
Journal of the Fisheries Research Board of Canada volume 28, issue 6, page 821-842 ISSN 0015-296X |
op_rights |
http://www.nrcresearchpress.com/page/about/CorporateTextAndDataMining |
op_doi |
https://doi.org/10.1139/f71-123 |
container_title |
Journal of the Fisheries Research Board of Canada |
container_volume |
28 |
container_issue |
6 |
container_start_page |
821 |
op_container_end_page |
842 |
_version_ |
1785573043197706240 |