Refining a Nordmøre-grid for a Brazilian artisanal penaeid-trawl fishery

Silva, Catarina NS, Broadhurst, Matt K., Schwingel, Andréia, Dias, José H., Cattani, André P., and Spach, Henry L. (2011) Refining a Nordmøre-grid for a Brazilian artisanal penaeid-trawl fishery. Fisheries Research, 109 (1). pp. 168-178.

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Abstract

Two experiments were done to assess and refine the Nordmøre-grid in a canoe-trawl fishery targeting Xiphopenaeus kroyeri off southern Brazil. During experiment 1, a codend containing a small (1881 cm2) Nordmøre-grid (24-mm bar spaces) retained significantly less total bycatch (mean predicted weight reduced by 56%), brachyurids (by 79%) and teleosts (by 50%) than a conventional configuration (control), without significantly affecting the weights or numbers of X. kroyeri, although mean predicted weights were 12% lower. During experiment 2, the bar spaces were subsequently maintained, but the grid area was increased by 1.4 while the extension section mesh size was reduced by 1.3, and the impacts of different materials (hollow vs. solid aluminium rod), bar diameter (10 vs. 16 mm) and presence/absence of a guiding panel were investigated. Most of these technical changes had minimal effects, with all grid configurations maintaining catches of X. kroyeri (at between −13 and +22% of the control) and significantly reducing total bycatch (up to 54%) and brachyurids (up to 90%). But, unlike the small grid, none of the large grids significantly reduced the catches of teleosts. This result was attributed to the increased distance required by fish smaller than the bar spaces to swim out of the escape exit. While ongoing refinements, including narrower bar spaces, could improve the performance of the Nordmøre-grid, the results justify the adoption of the generic configuration as a means for improving selectivity in this fishery.

Research highlights:

The Nordmøre-grid was assessed in a Brazilian artisanal penaeid-trawl fishery. All Nordmøre-grids reduced bycatch with no significant impact on target catches. The results justify the adoption of a generic Nordmøre-grid off southern Brazil.

Item ID: 49088
Item Type: Article (Research - C1)
ISSN: 1872-6763
Keywords: Penaeid trawl, Xiphopenaeus kroyeri, multi-species, fisheries management
Funders: Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Laboratório de Biologia de Peixes, Centro de Estudos do Mar (LBPCE), Reestruturação e Expansão das Universidades Federais (REUF), Programa Institucional de Bolsas de Iniciação Científica (PIBIC)
Date Deposited: 13 Jun 2017 05:30
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050205 Environmental Management @ 50%
05 ENVIRONMENTAL SCIENCES > 0502 Environmental Science and Management > 050202 Conservation and Biodiversity @ 50%
SEO Codes: 83 ANIMAL PRODUCTION AND ANIMAL PRIMARY PRODUCTS > 8302 Fisheries - Wild Caught > 830205 Wild Caught Prawns @ 50%
96 ENVIRONMENT > 9608 Flora, Fauna and Biodiversity > 960802 Coastal and Estuarine Flora, Fauna and Biodiversity @ 30%
96 ENVIRONMENT > 9605 Ecosystem Assessment and Management > 960503 Ecosystem Assessment and Management of Coastal and Estuarine Environments @ 20%
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