February 9, 2011 Featured Article Read More →

Nehrops gear modification trials

The twin-rig otter-trawl fishery for Nephrops is of significant economic importance, particularly on the west of Scotland, but as the fishery uses an 80 mm mesh there are  significant by-catch issues.

Under a Scottish Industry Science Partnership Project (003/09), trials were undertaken of a twin rig Nephrops trawl incorporating a large mesh top sheet aimed at reducing the bycatch of commercial gadoid species.

In the final report 03/10 the basic conclusion was that the gear modification tested did not appear to have a clear beneficial impact on fish by-catch although this could not be properly evaluated for larger cod as low numbers were caught overall; but for whiting and hake, the test net seemed to catch more, not less, smaller fish. 

Relatively large amounts of juvenile hake were caught on most hauls, something not seen previously by the skipper; this may reflect a change in stock status or distribution for this species which could mean the by-catch of hake by the west coast twin-rig fisheries may become an issue of concern.

In addition, however, other species such as cuckoo, blond and thornback ray and common skate were caught on most hauls and spurdog were also caught on some hauls. 

The report did note “The conservation status of elasmobranchs is of general concern with common skate and spurdog listed on the OSPAR List of Threatened and/or Declining Species and Habitats for the west of Scotland.  Future gear trials will need to consider not only reductions in the by-catch of gadoids but also reducing the by-catch of these incidental species if the twin-rig fisheries are to become more environmentally sustainable.

Posted in: Shark Bites
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