Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery
This study investigated the size selectivity and catch efficiency in the North-east Atlantic demersal trawl fishery targeting cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ). The use of a sorting grid followed by a size selective codend is compulsory in this fishery. Experimental fishi...
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Online Access: | https://hdl.handle.net/10037/19150 https://doi.org/10.1016/j.fishres.2020.105647 |
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ftunivtroemsoe:oai:munin.uit.no:10037/19150 2023-05-15T16:19:24+02:00 Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery Brinkhof, Jesse Larsen, Roger B. Herrmann, Bent Sistiaga, Manu 2020-07-28 https://hdl.handle.net/10037/19150 https://doi.org/10.1016/j.fishres.2020.105647 eng eng Elsevier Fisheries Research Brinkhof J, Larsen RBL, Herrmann B, Sistiaga MB. Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery. Fisheries Research. 2020;231 FRIDAID 1824728 doi:10.1016/j.fishres.2020.105647 0165-7836 1872-6763 https://hdl.handle.net/10037/19150 openAccess Copyright 2020 The Author(s) VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 Journal article Tidsskriftartikkel Peer reviewed publishedVersion 2020 ftunivtroemsoe https://doi.org/10.1016/j.fishres.2020.105647 2021-06-25T17:57:37Z This study investigated the size selectivity and catch efficiency in the North-east Atlantic demersal trawl fishery targeting cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ). The use of a sorting grid followed by a size selective codend is compulsory in this fishery. Experimental fishing was conducted with a commercially rigged trawl, flexigrid section, and diamond-mesh codend. The flexigrid section is a dual sorting system and all fish that escaped from the two grids in the flexigrid system and the codend were retained in separate covers. This allowed us to estimate the combined size selectivity of the system, as well as the separate contributions from the first grid, second grid, and codend. The catch efficiencies for cod and haddock below and above the minimum reference length (MRL) were quantified by estimating the values for a set of exploitation pattern indicators. The results showed that most fish escaped from the flexigrid section. Only a few fish below the MRL entered the codend and nearly all of them subsequently escaped through the codend meshes. The probability of retaining undersized cod and haddock was low with the combined system. Furthermore, the results showed that the probability of escape was high through the second grid in the system for fish above the MRL, and this finding was supported by the exploitation pattern indicators. In particular, the estimated exploitation pattern indicators showed that using the current MRL and the fish size distributions encountered during the trials, no haddock and only 2.3 % of cod below the MRL were retained by the gear. However, 77.4 % of the haddock and 16.0 % of the cod above the MRL were found to escape, thereby indicating poor catch efficiency, especially for haddock. These results demonstrate the importance of supplementing size selectivity research with estimates of the actual catch efficiency using the gear employed, which were quantified using exploitation pattern indicators in this study. Article in Journal/Newspaper Gadus morhua North East Atlantic University of Tromsø: Munin Open Research Archive Fisheries Research 231 105647 |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 |
spellingShingle |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 Brinkhof, Jesse Larsen, Roger B. Herrmann, Bent Sistiaga, Manu Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
topic_facet |
VDP::Agriculture and fishery disciplines: 900::Fisheries science: 920 VDP::Landbruks- og Fiskerifag: 900::Fiskerifag: 920 |
description |
This study investigated the size selectivity and catch efficiency in the North-east Atlantic demersal trawl fishery targeting cod ( Gadus morhua ) and haddock ( Melanogrammus aeglefinus ). The use of a sorting grid followed by a size selective codend is compulsory in this fishery. Experimental fishing was conducted with a commercially rigged trawl, flexigrid section, and diamond-mesh codend. The flexigrid section is a dual sorting system and all fish that escaped from the two grids in the flexigrid system and the codend were retained in separate covers. This allowed us to estimate the combined size selectivity of the system, as well as the separate contributions from the first grid, second grid, and codend. The catch efficiencies for cod and haddock below and above the minimum reference length (MRL) were quantified by estimating the values for a set of exploitation pattern indicators. The results showed that most fish escaped from the flexigrid section. Only a few fish below the MRL entered the codend and nearly all of them subsequently escaped through the codend meshes. The probability of retaining undersized cod and haddock was low with the combined system. Furthermore, the results showed that the probability of escape was high through the second grid in the system for fish above the MRL, and this finding was supported by the exploitation pattern indicators. In particular, the estimated exploitation pattern indicators showed that using the current MRL and the fish size distributions encountered during the trials, no haddock and only 2.3 % of cod below the MRL were retained by the gear. However, 77.4 % of the haddock and 16.0 % of the cod above the MRL were found to escape, thereby indicating poor catch efficiency, especially for haddock. These results demonstrate the importance of supplementing size selectivity research with estimates of the actual catch efficiency using the gear employed, which were quantified using exploitation pattern indicators in this study. |
format |
Article in Journal/Newspaper |
author |
Brinkhof, Jesse Larsen, Roger B. Herrmann, Bent Sistiaga, Manu |
author_facet |
Brinkhof, Jesse Larsen, Roger B. Herrmann, Bent Sistiaga, Manu |
author_sort |
Brinkhof, Jesse |
title |
Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
title_short |
Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
title_full |
Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
title_fullStr |
Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
title_full_unstemmed |
Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery |
title_sort |
size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the north-east atlantic gadoid fishery |
publisher |
Elsevier |
publishDate |
2020 |
url |
https://hdl.handle.net/10037/19150 https://doi.org/10.1016/j.fishres.2020.105647 |
genre |
Gadus morhua North East Atlantic |
genre_facet |
Gadus morhua North East Atlantic |
op_relation |
Fisheries Research Brinkhof J, Larsen RBL, Herrmann B, Sistiaga MB. Size selectivity and catch efficiency of bottom trawl with a double sorting grid and diamond mesh codend in the North-east Atlantic gadoid fishery. Fisheries Research. 2020;231 FRIDAID 1824728 doi:10.1016/j.fishres.2020.105647 0165-7836 1872-6763 https://hdl.handle.net/10037/19150 |
op_rights |
openAccess Copyright 2020 The Author(s) |
op_doi |
https://doi.org/10.1016/j.fishres.2020.105647 |
container_title |
Fisheries Research |
container_volume |
231 |
container_start_page |
105647 |
_version_ |
1766005795956195328 |