A new method for estimating length-dependent capture modes in gillnets: a case study in the Danish cod (Gadus morhua) fishery

Esther Savina*, Bent Herrmann, Rikke P. Frandsen, Ludvig A. Krag

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Gillnets are used world-wide for harvesting groundfish and pelagic species at sea and in freshwater. Little consideration has been given to how fish are caught in gillnets, even though the capture mode provides valuable information for understanding gear catchability. This paper describes a new method of estimating the length-dependent fish capture modes in gillnets. Using this method, we investigated the length-dependent capture modes for cod (Gadus morhua) in commercial monofilament nylon gillnets. Cod is a target species for several fisheries in the Northern Atlantic. This is the first time the capture mode was formally related to fish size with a direct representation of the experimental observations. The results demonstrated that gillnets are clearly designed for gilling. However, capture modes were size dependent, with small fish being caught by the mouth and larger fish by the maxillary. The application of the method is relevant when used by gear technologists to evaluate different gear characteristics to improve size or species selectivity. Changing the hanging ratio, for instance, or replacing nylon twine by thicker biodegradable material may considerably change the capture modes and their effect on gear efficiency.
Original languageEnglish
Article numberfsab267
JournalICES Journal of Marine Science
Volume79
Issue number2
Pages (from-to)373-381
Number of pages9
ISSN1054-3139
DOIs
Publication statusPublished - 2022

Keywords

  • Bottom-set net
  • Entangling
  • Gear efficiency
  • Gilling passive fishing gear
  • Size selectivity
  • Snagging
  • Wedging

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