Correcting density-dependent effects in abundance estimates from bottom-trawl surveys
Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the effic...
Published in: | ICES Journal of Marine Science |
---|---|
Main Authors: | , , |
Format: | Text |
Language: | English |
Published: |
Oxford University Press
2014
|
Subjects: | |
Online Access: | http://icesjms.oxfordjournals.org/cgi/content/short/71/5/1107 https://doi.org/10.1093/icesjms/fst208 |
id |
fthighwire:oai:open-archive.highwire.org:icesjms:71/5/1107 |
---|---|
record_format |
openpolar |
spelling |
fthighwire:oai:open-archive.highwire.org:icesjms:71/5/1107 2023-05-15T15:43:56+02:00 Correcting density-dependent effects in abundance estimates from bottom-trawl surveys Kotwicki, Stan Ianelli, James N. Punt, André E. 2014-08-01 00:00:00.0 text/html http://icesjms.oxfordjournals.org/cgi/content/short/71/5/1107 https://doi.org/10.1093/icesjms/fst208 en eng Oxford University Press http://icesjms.oxfordjournals.org/cgi/content/short/71/5/1107 http://dx.doi.org/10.1093/icesjms/fst208 Copyright (C) 2014, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer Original Articles TEXT 2014 fthighwire https://doi.org/10.1093/icesjms/fst208 2015-02-28T22:23:13Z Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the efficiency of the survey bottom trawl (BT) for some species can be density-dependent, which could affect the reliability of survey-derived indices of abundance. A function q e ∼ f ( u ), where q e is the BT efficiency and u the catch rate, was derived using experimentally derived acoustic dead-zone correction and BT efficiency parameters obtained from combining a subset of BT catch data with synchronously collected acoustic data from walleye pollock ( Theragra chalcogramma ) in the eastern Bering Sea (EBS). We found that q e decreased with increasing BT catches resulting in hyperstability of the index of abundance derived from BT survey. Density-dependent q e resulted in spatially and temporarily variable bias in survey cpue and biased population age structure derived from survey data. We used the relationship q e ∼ f ( u ) to correct the EBS trawl survey index of abundance for density-dependence. We also obtained a variance–covariance matrix for a new index that accounted for sampling variability and the uncertainty associated with the q e . We found that incorporating estimates of the new index of abundance changed outputs from the walleye pollock stock assessment model. Although changes were minor, we advocate incorporating estimates of density-dependent q e into the walleye pollock stock assessment as a precautionary measure that should be undertaken to avoid negative consequences of the density-dependent q e . Text Bering Sea Theragra chalcogramma HighWire Press (Stanford University) Bering Sea ICES Journal of Marine Science 71 5 1107 1116 |
institution |
Open Polar |
collection |
HighWire Press (Stanford University) |
op_collection_id |
fthighwire |
language |
English |
topic |
Original Articles |
spellingShingle |
Original Articles Kotwicki, Stan Ianelli, James N. Punt, André E. Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
topic_facet |
Original Articles |
description |
Indices of abundance are important for estimating population trends in stock assessment and ideally should be based on fishery-independent surveys to avoid problems associated with the hyperstability of the commercial catch per unit effort (cpue) data. However, recent studies indicate that the efficiency of the survey bottom trawl (BT) for some species can be density-dependent, which could affect the reliability of survey-derived indices of abundance. A function q e ∼ f ( u ), where q e is the BT efficiency and u the catch rate, was derived using experimentally derived acoustic dead-zone correction and BT efficiency parameters obtained from combining a subset of BT catch data with synchronously collected acoustic data from walleye pollock ( Theragra chalcogramma ) in the eastern Bering Sea (EBS). We found that q e decreased with increasing BT catches resulting in hyperstability of the index of abundance derived from BT survey. Density-dependent q e resulted in spatially and temporarily variable bias in survey cpue and biased population age structure derived from survey data. We used the relationship q e ∼ f ( u ) to correct the EBS trawl survey index of abundance for density-dependence. We also obtained a variance–covariance matrix for a new index that accounted for sampling variability and the uncertainty associated with the q e . We found that incorporating estimates of the new index of abundance changed outputs from the walleye pollock stock assessment model. Although changes were minor, we advocate incorporating estimates of density-dependent q e into the walleye pollock stock assessment as a precautionary measure that should be undertaken to avoid negative consequences of the density-dependent q e . |
format |
Text |
author |
Kotwicki, Stan Ianelli, James N. Punt, André E. |
author_facet |
Kotwicki, Stan Ianelli, James N. Punt, André E. |
author_sort |
Kotwicki, Stan |
title |
Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
title_short |
Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
title_full |
Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
title_fullStr |
Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
title_full_unstemmed |
Correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
title_sort |
correcting density-dependent effects in abundance estimates from bottom-trawl surveys |
publisher |
Oxford University Press |
publishDate |
2014 |
url |
http://icesjms.oxfordjournals.org/cgi/content/short/71/5/1107 https://doi.org/10.1093/icesjms/fst208 |
geographic |
Bering Sea |
geographic_facet |
Bering Sea |
genre |
Bering Sea Theragra chalcogramma |
genre_facet |
Bering Sea Theragra chalcogramma |
op_relation |
http://icesjms.oxfordjournals.org/cgi/content/short/71/5/1107 http://dx.doi.org/10.1093/icesjms/fst208 |
op_rights |
Copyright (C) 2014, International Council for the Exploration of the Sea/Conseil International pour l'Exploration de la Mer |
op_doi |
https://doi.org/10.1093/icesjms/fst208 |
container_title |
ICES Journal of Marine Science |
container_volume |
71 |
container_issue |
5 |
container_start_page |
1107 |
op_container_end_page |
1116 |
_version_ |
1766378153384607744 |