The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology
The northern rockfish, Sebastes polyspinis, is the second most abundant rockfish in Alaska, and it supports a valuable trawl fishery. Little information is available, however, on either the biology of this species or its commercial fishery. To provide a synopsis of information on northern rockfish i...
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ftaquaticcommons:oai:generic.eprints.org:9739 2023-05-15T17:04:39+02:00 The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology Clausen, David M. Heifetz, Jonathan 2002 application/pdf http://aquaticcommons.org/9739/ http://spo.nwr.noaa.gov/mfr644/mfr6441.pdf http://aquaticcommons.org/9739/1/mfr6441.pdf en eng http://aquaticcommons.org/9739/1/mfr6441.pdf Clausen, David M. and Heifetz, Jonathan (2002) The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology. Marine Fisheries Review, 64(4), pp. 1-28. Biology Ecology Fisheries Article PeerReviewed 2002 ftaquaticcommons 2020-02-27T09:23:51Z The northern rockfish, Sebastes polyspinis, is the second most abundant rockfish in Alaska, and it supports a valuable trawl fishery. Little information is available, however, on either the biology of this species or its commercial fishery. To provide a synopsis of information on northern rockfish in Alaska, this study examined data for this species from commercial fishery observations in 1990–98 and from fishery-independent trawl surveys in 1980–99. Nearly all the commercial catch came from bottom trawling, mostly by large factory-trawlers, although smaller shore-based trawlers in recent years took an increasing portion of the catch in the Gulf of Alaska. Most of the northern rockfish catch in the Gulf of Alaska was taken by a directed fishery, whereas that of the Aleutian Islands predominantly came as discarded bycatch in the Atka mackerel fishery. In both regions, most of the catch was taken from a number of relatively small and discrete fishing grounds at depths of 75–150 m in the Gulf of Alaska and 75–175 m in the Aleutian Islands. These grounds, especially in the Gulf of Alaska, are on shallow rises or banks located on the outer continental shelf, and often are surrounded by deeper water. Five fishing grounds were identified in the Gulf of Alaska, and eleven in the Aleutian Islands. One fishing ground in the Gulf of Alaska, the “Snakehead” south of Kodiak Island, accounted for 46% of the total northern rockfish catch in this region. Analysis of the survey data generally revealed similar patterns of geographic distribution as those seen in the fishery, although some of the commercial fishing grounds did not stand out as areas of special abundance in the surveys. The surveys also found two areas of abundance that were not evident in the fishery data. Relatively few juvenile northern rockfish were caught in any of the surveys, but those taken in the Gulf of Alaska tended to occur more inshore and at shallower depths than adults. Individual size of northern rockfish was substantially larger in the Gulf of Alaska than in the Aleutian Islands according to both fishery and survey data. Analysis of age data from each region supports this, as Gulf of Alaska fish were found to grow significantly faster and reach a larger maximum length than those in the Aleutian Islands. Sex ratio in the Gulf of Alaska was nearly 50:50, but females predominated in the Aleutian Islands by a ratio of 57:43. In both regions, size of females was significantly larger than males. Article in Journal/Newspaper Kodiak Alaska Aleutian Islands International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons Atka ENVELOPE(151.789,151.789,60.835,60.835) Fishing Ground ENVELOPE(-55.848,-55.848,49.550,49.550) Gulf of Alaska |
institution |
Open Polar |
collection |
International Association of Aquatic and Marine Science Libraries and Information Centers (IAMSLIC): Aquatic Commons |
op_collection_id |
ftaquaticcommons |
language |
English |
topic |
Biology Ecology Fisheries |
spellingShingle |
Biology Ecology Fisheries Clausen, David M. Heifetz, Jonathan The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
topic_facet |
Biology Ecology Fisheries |
description |
The northern rockfish, Sebastes polyspinis, is the second most abundant rockfish in Alaska, and it supports a valuable trawl fishery. Little information is available, however, on either the biology of this species or its commercial fishery. To provide a synopsis of information on northern rockfish in Alaska, this study examined data for this species from commercial fishery observations in 1990–98 and from fishery-independent trawl surveys in 1980–99. Nearly all the commercial catch came from bottom trawling, mostly by large factory-trawlers, although smaller shore-based trawlers in recent years took an increasing portion of the catch in the Gulf of Alaska. Most of the northern rockfish catch in the Gulf of Alaska was taken by a directed fishery, whereas that of the Aleutian Islands predominantly came as discarded bycatch in the Atka mackerel fishery. In both regions, most of the catch was taken from a number of relatively small and discrete fishing grounds at depths of 75–150 m in the Gulf of Alaska and 75–175 m in the Aleutian Islands. These grounds, especially in the Gulf of Alaska, are on shallow rises or banks located on the outer continental shelf, and often are surrounded by deeper water. Five fishing grounds were identified in the Gulf of Alaska, and eleven in the Aleutian Islands. One fishing ground in the Gulf of Alaska, the “Snakehead” south of Kodiak Island, accounted for 46% of the total northern rockfish catch in this region. Analysis of the survey data generally revealed similar patterns of geographic distribution as those seen in the fishery, although some of the commercial fishing grounds did not stand out as areas of special abundance in the surveys. The surveys also found two areas of abundance that were not evident in the fishery data. Relatively few juvenile northern rockfish were caught in any of the surveys, but those taken in the Gulf of Alaska tended to occur more inshore and at shallower depths than adults. Individual size of northern rockfish was substantially larger in the Gulf of Alaska than in the Aleutian Islands according to both fishery and survey data. Analysis of age data from each region supports this, as Gulf of Alaska fish were found to grow significantly faster and reach a larger maximum length than those in the Aleutian Islands. Sex ratio in the Gulf of Alaska was nearly 50:50, but females predominated in the Aleutian Islands by a ratio of 57:43. In both regions, size of females was significantly larger than males. |
format |
Article in Journal/Newspaper |
author |
Clausen, David M. Heifetz, Jonathan |
author_facet |
Clausen, David M. Heifetz, Jonathan |
author_sort |
Clausen, David M. |
title |
The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
title_short |
The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
title_full |
The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
title_fullStr |
The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
title_full_unstemmed |
The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology |
title_sort |
northern rockfish, sebastes polyspinis, in alaska: commercial fishery, distribution, and biology |
publishDate |
2002 |
url |
http://aquaticcommons.org/9739/ http://spo.nwr.noaa.gov/mfr644/mfr6441.pdf http://aquaticcommons.org/9739/1/mfr6441.pdf |
long_lat |
ENVELOPE(151.789,151.789,60.835,60.835) ENVELOPE(-55.848,-55.848,49.550,49.550) |
geographic |
Atka Fishing Ground Gulf of Alaska |
geographic_facet |
Atka Fishing Ground Gulf of Alaska |
genre |
Kodiak Alaska Aleutian Islands |
genre_facet |
Kodiak Alaska Aleutian Islands |
op_relation |
http://aquaticcommons.org/9739/1/mfr6441.pdf Clausen, David M. and Heifetz, Jonathan (2002) The Northern Rockfish, Sebastes polyspinis, in Alaska: Commercial Fishery, Distribution, and Biology. Marine Fisheries Review, 64(4), pp. 1-28. |
_version_ |
1766058962361253888 |