Study

The selective properties of some sieve nets

Actions

This study is summarised as evidence for the following.

Action Category

Fit a size-sorting mesh funnel (a sieve net) to a prawn/shrimp trawl net

Action Link
Marine Fish Conservation
  1. Fit a size-sorting mesh funnel (a sieve net) to a prawn/shrimp trawl net

    A replicated, paired, controlled study in 1999–2000 of bottom fishing grounds in the North Sea, England, UK (Revill & Holst 2004) found that shrimp trawl nets fitted with a sieve net (four designs) caught fewer unwanted fish compared to a conventional trawl without a sieve net. Across all four sieve net designs, average catch numbers of unwanted fish were lower in trawls with a sieve net compared to without, for: plaice Pleuronectes platessa (with: 9–15 fish/haul, 12–21 fish/haul), dab Limanda limanda (with: 14–35 fish/haul, 8–55 fish/haul) and whiting Merlangius merlangus (with: 64–133 fish/haul, 73–151 fish/haul). In addition, overall discarded catch (fish and invertebrates combined) was reduced in sieve nets by 56–90% in weight, and losses of target brown shrimp Crangon crangon ranged between 8–21%. Paired deployments were undertaken in The Wash fishing grounds using standard shrimp trawls (20 mm mesh codend) fitted with one of four sieve net designs (see original paper for specifications) and standard shrimp trawls without sieve nets. Trawls were towed at 2–3 knots for 1 h and 480 tows were completed.

    (Summarised by: Leo Clarke)

Output references
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