Study

Evaluation of shrimp trawls equipped with bycatch reduction devices in inshore waters of Louisiana

  • Published source details Rogers D.R., Rogers B.D., de Silva J.A., Wright V.L. & Watson J.W. (1997) Evaluation of shrimp trawls equipped with bycatch reduction devices in inshore waters of Louisiana. Fisheries Research, 33, 55-72

Actions

This study is summarised as evidence for the following.

Action Category

Fit large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets

Action Link
Marine Fish Conservation
  1. Fit large, supported escape openings (such as Fisheyes, Bigeyes and radial escape sections) to trawl nets

    A replicated, paired, controlled study in 1993 of three coastal seabed areas in the Gulf of Mexico, USA (Rogers et al. 1997) found that shrimp trawl codends fitted with large, supported openings (single or radial), reduced the unwanted fish catch compared to unmodified codends without escape openings. For seven of eight different designs of escape opening devices, fish catch was reduced by 22–55% in number (with: 74–248 fish/tow, without: 124–422 fish/tow), and by 27–62% in weight (with: 1,127–2,750 g/tow, without: 2,152–5,530 g/tow). One of eight designs had a 50% lower weight of unwanted fish than a net without escape openings (with:1,245 g/tow, without: 2,489 g/tow) but catch numbers were similar (with:177 fish/tow, without: 170 fish/tow). Target commercial shrimp Penaeidae catches were reduced by 5–39% in number (5–35% in weight) across all eight designs of escape opening devices, however three were not statistically different to catches without a device. Data were collected in spring and autumn 1993 during the shrimp fishing seasons from 36 twin trawl deployments (12/area/season). They were done using a net with one of four designs of supported escape openings towed simultaneously with an unmodified net. In the autumn, modified versions of each of the original four escape opening designs were tested in the same way. Escape opening devices consisted of either a single large framed opening or a section of large mesh openings running around the net circumference. Each design also had a mesh guiding funnel inside the net leading to the escape sections (see original paper for full specifications). Fish and shrimp in each codend were identified, counted and weighed in the laboratory.

    (Summarised by: Khatija Alliji)

Output references

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