Predicting optimal combinations of by-catch reduction devices in trawl gears: a meta-analytical approach

Valentina Melli*, Bent Herrmann, Junita Diana Karlsen, Jordan P. Feekings, Ludvig Ahm Krag

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Global efforts to reduce unwanted catches have led to the development of a vast array of bycatch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta-analytical approach that combines the data available on BRDs tested independently in a fishery and predict the theoretical selectivity of all possible combinations of those devices. This allows to identify promising BRD combinations, worth experimental investigation and flexible trawl configurations, where the selectivity can be substantially modified by adding or removing one BRD, thus aiding fishermen in adapting to high variability in catch composition and quota availability. To illustrate the approach, we used BRDs developed for the well-studied Nephrops (Nephrops norvegicus, Nephropidae) directed mixed trawl fishery in the Skagerrak and Kattegat seas. We predicted the selectivity of 100 BRD combinations for Nephrops, cod (Gadus morhua, Gadidae) and haddock (Melanogrammus aeglefinus, Gadidae), compared them in terms of absolute selectivity and performance under realistic catch scenarios, from both single- and multi-species perspectives, and identified 15 BRD combinations that could be worth future experimental investigation. The meta-analytical approach makes best use of existing knowledge and leads to new insights about the potential for improvement and flexibility in trawl selectivity. This could benefit a variety of mixed trawl fisheries and help developing a new generation of more flexible gears, with multiple BRDs integrated in their structure.
Original languageEnglish
JournalFish and Fisheries
Number of pages42
ISSN1467-2960
DOIs
Publication statusAccepted/In press - 2020

Keywords

  • Combined selectivity
  • Flexible trawl design
  • Gear modifications
  • Mixed trawl fisheries
  • Optimal gear design
  • Trawl selectivity

Cite this

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title = "Predicting optimal combinations of by-catch reduction devices in trawl gears: a meta-analytical approach",
abstract = "Global efforts to reduce unwanted catches have led to the development of a vast array of bycatch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta-analytical approach that combines the data available on BRDs tested independently in a fishery and predict the theoretical selectivity of all possible combinations of those devices. This allows to identify promising BRD combinations, worth experimental investigation and flexible trawl configurations, where the selectivity can be substantially modified by adding or removing one BRD, thus aiding fishermen in adapting to high variability in catch composition and quota availability. To illustrate the approach, we used BRDs developed for the well-studied Nephrops (Nephrops norvegicus, Nephropidae) directed mixed trawl fishery in the Skagerrak and Kattegat seas. We predicted the selectivity of 100 BRD combinations for Nephrops, cod (Gadus morhua, Gadidae) and haddock (Melanogrammus aeglefinus, Gadidae), compared them in terms of absolute selectivity and performance under realistic catch scenarios, from both single- and multi-species perspectives, and identified 15 BRD combinations that could be worth future experimental investigation. The meta-analytical approach makes best use of existing knowledge and leads to new insights about the potential for improvement and flexibility in trawl selectivity. This could benefit a variety of mixed trawl fisheries and help developing a new generation of more flexible gears, with multiple BRDs integrated in their structure.",
keywords = "Combined selectivity, Flexible trawl design, Gear modifications, Mixed trawl fisheries, Optimal gear design, Trawl selectivity",
author = "Valentina Melli and Bent Herrmann and Karlsen, {Junita Diana} and Feekings, {Jordan P.} and Krag, {Ludvig Ahm}",
year = "2020",
doi = "10.1111/faf.12428",
language = "English",
journal = "Fish and Fisheries",
issn = "1467-2960",
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T1 - Predicting optimal combinations of by-catch reduction devices in trawl gears: a meta-analytical approach

AU - Melli, Valentina

AU - Herrmann, Bent

AU - Karlsen, Junita Diana

AU - Feekings, Jordan P.

AU - Krag, Ludvig Ahm

PY - 2020

Y1 - 2020

N2 - Global efforts to reduce unwanted catches have led to the development of a vast array of bycatch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta-analytical approach that combines the data available on BRDs tested independently in a fishery and predict the theoretical selectivity of all possible combinations of those devices. This allows to identify promising BRD combinations, worth experimental investigation and flexible trawl configurations, where the selectivity can be substantially modified by adding or removing one BRD, thus aiding fishermen in adapting to high variability in catch composition and quota availability. To illustrate the approach, we used BRDs developed for the well-studied Nephrops (Nephrops norvegicus, Nephropidae) directed mixed trawl fishery in the Skagerrak and Kattegat seas. We predicted the selectivity of 100 BRD combinations for Nephrops, cod (Gadus morhua, Gadidae) and haddock (Melanogrammus aeglefinus, Gadidae), compared them in terms of absolute selectivity and performance under realistic catch scenarios, from both single- and multi-species perspectives, and identified 15 BRD combinations that could be worth future experimental investigation. The meta-analytical approach makes best use of existing knowledge and leads to new insights about the potential for improvement and flexibility in trawl selectivity. This could benefit a variety of mixed trawl fisheries and help developing a new generation of more flexible gears, with multiple BRDs integrated in their structure.

AB - Global efforts to reduce unwanted catches have led to the development of a vast array of bycatch reduction devices (BRDs), in particular for mixed trawl fisheries. Some of these BRDs could likely benefit from being combined. However, the number of possible combinations would be prohibitive to be tested experimentally. Therefore, in this study we propose a meta-analytical approach that combines the data available on BRDs tested independently in a fishery and predict the theoretical selectivity of all possible combinations of those devices. This allows to identify promising BRD combinations, worth experimental investigation and flexible trawl configurations, where the selectivity can be substantially modified by adding or removing one BRD, thus aiding fishermen in adapting to high variability in catch composition and quota availability. To illustrate the approach, we used BRDs developed for the well-studied Nephrops (Nephrops norvegicus, Nephropidae) directed mixed trawl fishery in the Skagerrak and Kattegat seas. We predicted the selectivity of 100 BRD combinations for Nephrops, cod (Gadus morhua, Gadidae) and haddock (Melanogrammus aeglefinus, Gadidae), compared them in terms of absolute selectivity and performance under realistic catch scenarios, from both single- and multi-species perspectives, and identified 15 BRD combinations that could be worth future experimental investigation. The meta-analytical approach makes best use of existing knowledge and leads to new insights about the potential for improvement and flexibility in trawl selectivity. This could benefit a variety of mixed trawl fisheries and help developing a new generation of more flexible gears, with multiple BRDs integrated in their structure.

KW - Combined selectivity

KW - Flexible trawl design

KW - Gear modifications

KW - Mixed trawl fisheries

KW - Optimal gear design

KW - Trawl selectivity

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JO - Fish and Fisheries

JF - Fish and Fisheries

SN - 1467-2960

ER -