Study

Evaluation of the Morrison soft turtle excluder device: prawn and bycatch variation in Moreton Bay, Queensland

  • Published source details Robins-Troeger J.B. (1994) Evaluation of the Morrison soft turtle excluder device: prawn and bycatch variation in Moreton Bay, Queensland. Fisheries Research, 19, 205-217

Actions

This study is summarised as evidence for the following.

Action Category

Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net

Action Link
Marine Fish Conservation
  1. Fit a size-sorting escape grid (rigid or flexible) to a prawn/shrimp trawl net

    A replicated, paired, controlled study in 1991–1992 at one coastal seabed and one estuarine site in the Coral Sea, Australia (Robins-Troeger 1994) found that using a flexible (mesh) size-sorting escape grid (a Morrison soft turtle excluder device) inside a prawn trawl net resulted in variable reductions of unwanted non-commercial catch (fish and crustaceans) compared to nets without a grid. The reductions in weight (21–32%) of unwanted catch (fish and crustaceans) in nets with a flexible escape grid were significant at both sites in 1991, but not in 1992 (2–18%). In addition, larger unwanted non-commercial catch including stingrays Amphotistius kuhlii and shovelnose rays Rhinobatus batillum were not caught in nets with a flexible escape grid, but they were occasionally caught in nets without an escape grid (numbers not reported). Prawn catch (Metapenaeus bennettae, Penaeus plebejus, Penaeus esculentus) was significantly reduced (17–30%) in nets with a grid at one site in 1991 and both sites in 1992. Paired fishing deployments were done on a research vessel towing two prawn trawl nets at two sites in Moreton Bay off Queensland in May 1991 (low prawn catches) and January 1992 (high prawn catches). A flexible grid made of 150 mm monofilament mesh was installed inside one trawl net and the other net was unmodified. In each year, 17 to 23 deployments of 45–100 min were completed at each site. Codend catches were landed and processed separately.

    (Summarised by: Khatija Alliji)

Output references

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