Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools
—Rockfishes (Sebastes spp.) are an important component of North Pacific marine ecosystems and commercial fisheries. Because the rocky, high-relief substrate that rockfishes often inhabit is inaccessible to standard survey trawls, population abundance assessments for many rockfish species are difficu...
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ftuninhampshire:oai:scholars.unh.edu:ccom-2095 2023-05-15T17:04:42+02:00 Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools Jones, Darin Wilson, Christopher D de Robertis, Alex Rooper, Chris Weber, Thomas C. Butler, John L 2012-01-01T08:00:00Z application/pdf https://scholars.unh.edu/ccom/1095 https://scholars.unh.edu/cgi/viewcontent.cgi?article=2095&context=ccom unknown University of New Hampshire Scholars' Repository https://scholars.unh.edu/ccom/1095 https://scholars.unh.edu/cgi/viewcontent.cgi?article=2095&context=ccom Center for Coastal and Ocean Mapping Marine Biology Oceanography and Atmospheric Sciences and Meteorology text 2012 ftuninhampshire 2023-01-30T21:33:29Z —Rockfishes (Sebastes spp.) are an important component of North Pacific marine ecosystems and commercial fisheries. Because the rocky, high-relief substrate that rockfishes often inhabit is inaccessible to standard survey trawls, population abundance assessments for many rockfish species are difficult. As part of a large study to classify substrate and compare complementary sampling tools, we investigated the feasibility of using an acoustic survey in conjunction with a lowered stereo-video camera, a remotely operated vehicle, and a modified bottom trawl to estimate rockfish biomass in untrawlable habitat. The Snakehead Bank south of Kodiak Island, Alaska, was surveyed repeatedly over 4 days and nights. Dusky rockfish (S. variabilis), northern rockfish (S. polyspinis), and harlequin rockfish (S. variegatus) were the most abundant species observed on the bank. Backscatter attributed to rockfish were collected primarily near the seafloor at a mean height off the bottom of 1.5 m. Total rockfish backscatter and the height of backscatter off the bottom did not differ among survey passes or between night and day. Biomass estimates for the 41 square nautical-mile area surveyed on this small, predominantly untrawlable bank were 2350 metric tons (t) of dusky rockfish, 331 t of northern rockfish, and 137 t of harlequin rockfish. These biomass estimates are 5–60 times the density estimated for these rockfish species by a regularly conducted bottom trawl survey covering the bank and the surrounding shelf. This finding shows that bottom trawl surveys can underestimate the abundance of rockfishes in untrawlable areas and, therefore, may underestimate overall population abundance for these species. Text Kodiak Alaska University of New Hampshire: Scholars Repository Pacific |
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University of New Hampshire: Scholars Repository |
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Marine Biology Oceanography and Atmospheric Sciences and Meteorology |
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Marine Biology Oceanography and Atmospheric Sciences and Meteorology Jones, Darin Wilson, Christopher D de Robertis, Alex Rooper, Chris Weber, Thomas C. Butler, John L Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
topic_facet |
Marine Biology Oceanography and Atmospheric Sciences and Meteorology |
description |
—Rockfishes (Sebastes spp.) are an important component of North Pacific marine ecosystems and commercial fisheries. Because the rocky, high-relief substrate that rockfishes often inhabit is inaccessible to standard survey trawls, population abundance assessments for many rockfish species are difficult. As part of a large study to classify substrate and compare complementary sampling tools, we investigated the feasibility of using an acoustic survey in conjunction with a lowered stereo-video camera, a remotely operated vehicle, and a modified bottom trawl to estimate rockfish biomass in untrawlable habitat. The Snakehead Bank south of Kodiak Island, Alaska, was surveyed repeatedly over 4 days and nights. Dusky rockfish (S. variabilis), northern rockfish (S. polyspinis), and harlequin rockfish (S. variegatus) were the most abundant species observed on the bank. Backscatter attributed to rockfish were collected primarily near the seafloor at a mean height off the bottom of 1.5 m. Total rockfish backscatter and the height of backscatter off the bottom did not differ among survey passes or between night and day. Biomass estimates for the 41 square nautical-mile area surveyed on this small, predominantly untrawlable bank were 2350 metric tons (t) of dusky rockfish, 331 t of northern rockfish, and 137 t of harlequin rockfish. These biomass estimates are 5–60 times the density estimated for these rockfish species by a regularly conducted bottom trawl survey covering the bank and the surrounding shelf. This finding shows that bottom trawl surveys can underestimate the abundance of rockfishes in untrawlable areas and, therefore, may underestimate overall population abundance for these species. |
format |
Text |
author |
Jones, Darin Wilson, Christopher D de Robertis, Alex Rooper, Chris Weber, Thomas C. Butler, John L |
author_facet |
Jones, Darin Wilson, Christopher D de Robertis, Alex Rooper, Chris Weber, Thomas C. Butler, John L |
author_sort |
Jones, Darin |
title |
Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
title_short |
Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
title_full |
Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
title_fullStr |
Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
title_full_unstemmed |
Evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
title_sort |
evaluation of rockfish abundance in untrawlable habitat: combining acoustic and complementary sampling tools |
publisher |
University of New Hampshire Scholars' Repository |
publishDate |
2012 |
url |
https://scholars.unh.edu/ccom/1095 https://scholars.unh.edu/cgi/viewcontent.cgi?article=2095&context=ccom |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Kodiak Alaska |
genre_facet |
Kodiak Alaska |
op_source |
Center for Coastal and Ocean Mapping |
op_relation |
https://scholars.unh.edu/ccom/1095 https://scholars.unh.edu/cgi/viewcontent.cgi?article=2095&context=ccom |
_version_ |
1766059029827682304 |