Estimating escapement of fish and invertebrates in a Danish anchor seine

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Abstract

The codend is generally presumed to be the place where the main selectivity of fish occurs in towed fishing gears, but other parts of the net have been found to contribute to the selectivity process of several invertebrate species. This means that conventional selectivity or survival studies may ignore the selectivity of net parts other than the codend for certain species. By attaching 12 small meshed collecting bags to different parts of a Danish anchor seine net and conducting normal commercial fishing activities, this study showed that there is a substantial escapement of fish and (especially) invertebrates from the forward parts of the seine net. For seven species of demersal fish, most fish escaped through the lower panel close to the codend. All invertebrate species were found in higher numbers in the collecting bags than in the codend where many organisms escaped in the lower panel of the wings or the belly. Mean levels of visible damage ranged from 1.00 to 3.25 for collected invertebrates and were similar for all gear parts. Common starfish (Asterias rubens), however, showed highest damage in the extension part of the net.
Original languageEnglish
JournalICES Journal of Marine Science
Volume74
Issue number9
Pages (from-to)2480-2488
ISSN1054-3139
DOIs
Publication statusPublished - 2017

Keywords

  • Damage Index
  • Ecosystem effects
  • Sea bed impacts
  • Selectivity
  • Skagerrak
  • Unaccounted mortality

Cite this

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title = "Estimating escapement of fish and invertebrates in a Danish anchor seine",
abstract = "The codend is generally presumed to be the place where the main selectivity of fish occurs in towed fishing gears, but other parts of the net have been found to contribute to the selectivity process of several invertebrate species. This means that conventional selectivity or survival studies may ignore the selectivity of net parts other than the codend for certain species. By attaching 12 small meshed collecting bags to different parts of a Danish anchor seine net and conducting normal commercial fishing activities, this study showed that there is a substantial escapement of fish and (especially) invertebrates from the forward parts of the seine net. For seven species of demersal fish, most fish escaped through the lower panel close to the codend. All invertebrate species were found in higher numbers in the collecting bags than in the codend where many organisms escaped in the lower panel of the wings or the belly. Mean levels of visible damage ranged from 1.00 to 3.25 for collected invertebrates and were similar for all gear parts. Common starfish (Asterias rubens), however, showed highest damage in the extension part of the net.",
keywords = "Damage Index, Ecosystem effects, Sea bed impacts, Selectivity, Skagerrak, Unaccounted mortality",
author = "Thomas Noack and Niels Madsen and Bernd Mieske and Rikke Frandsen and Kai Wieland and Krag, {Ludvig Ahm}",
year = "2017",
doi = "10.1093/icesjms/fsx066",
language = "English",
volume = "74",
pages = "2480--2488",
journal = "I C E S Journal of Marine Science",
issn = "1054-3139",
publisher = "Oxford University Press",
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Estimating escapement of fish and invertebrates in a Danish anchor seine. / Noack, Thomas; Madsen, Niels; Mieske, Bernd; Frandsen, Rikke; Wieland, Kai; Krag, Ludvig Ahm.

In: ICES Journal of Marine Science, Vol. 74, No. 9, 2017, p. 2480-2488.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Estimating escapement of fish and invertebrates in a Danish anchor seine

AU - Noack, Thomas

AU - Madsen, Niels

AU - Mieske, Bernd

AU - Frandsen, Rikke

AU - Wieland, Kai

AU - Krag, Ludvig Ahm

PY - 2017

Y1 - 2017

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AB - The codend is generally presumed to be the place where the main selectivity of fish occurs in towed fishing gears, but other parts of the net have been found to contribute to the selectivity process of several invertebrate species. This means that conventional selectivity or survival studies may ignore the selectivity of net parts other than the codend for certain species. By attaching 12 small meshed collecting bags to different parts of a Danish anchor seine net and conducting normal commercial fishing activities, this study showed that there is a substantial escapement of fish and (especially) invertebrates from the forward parts of the seine net. For seven species of demersal fish, most fish escaped through the lower panel close to the codend. All invertebrate species were found in higher numbers in the collecting bags than in the codend where many organisms escaped in the lower panel of the wings or the belly. Mean levels of visible damage ranged from 1.00 to 3.25 for collected invertebrates and were similar for all gear parts. Common starfish (Asterias rubens), however, showed highest damage in the extension part of the net.

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KW - Sea bed impacts

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KW - Skagerrak

KW - Unaccounted mortality

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