Confounding effects of knot orientation in penaeid trawls

Broadhurst, Matt K., Sterling, David J. and Millar, Russell B. (2016) Confounding effects of knot orientation in penaeid trawls. Fisheries Research, 179 124-130. doi:10.1016/j.fishres.2016.02.020


Author Broadhurst, Matt K.
Sterling, David J.
Millar, Russell B.
Title Confounding effects of knot orientation in penaeid trawls
Journal name Fisheries Research   Check publisher's open access policy
ISSN 0165-7836
1872-6763
Publication date 2016-07-01
Year available 2016
Sub-type Article (original research)
DOI 10.1016/j.fishres.2016.02.020
Open Access Status Not Open Access
Volume 179
Start page 124
End page 130
Total pages 7
Place of publication Amsterdam, Netherlands
Publisher Elsevier
Collection year 2016
Language eng
Formatted abstract
This study assessed the potential for confounding engineering and/or catching effects due to different knot (‘sheet bend’) orientations (and therefore positive or negative hydrodynamic lift) in the principal horizontal panels of a penaeid trawl. During 24 paired comparisons, orientating all meshes in the top and bottom belly panels of a trawl to produce a negative angle of attack (AOA) for all knots resulted in greater wing-end spread, and lower catches of school prawns, Metapenaeus macleayi per hectre trawled (means reduced by up to 26%) and three key species of schooling fish (by up to 67%), but more debris (4×) than when the meshes were orientated to produce a positive AOA. By comparison, catches of two other benthic fish remained unaffected by knot orientation. These catch differences were attributed to the negative-AOA trawl potentially assuming a considerably lower position in the water column (and species-specific orientations). The results demonstrate that it is essential to maintain consistency in knot orientation in penaeid trawls when testing gear modifications and/or during fishery-dependent or -independent surveys.
Keyword Knots
Penaeids
Selectivity
Trawl efficiency
Trawl surveys
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: HERDC Pre-Audit
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