Can bycatch in a flatfish gillnet fishery be reduced with rectangular mesh?

  • Published source details Rudershausen P.J., Price A.B. & Buckel J.A. (2015) Can bycatch in a flatfish gillnet fishery be reduced with rectangular mesh?. Fisheries Management and Ecology, 22, 419-431.


This study is summarised as evidence for the following.

Action Category

Modify gillnet or entangling (trammel/tangle) net configuration

Action Link
Marine Fish Conservation
  1. Modify gillnet or entangling (trammel/tangle) net configuration

    A replicated, paired, controlled study in 2010–2013 of two estuaries in North Carolina, USA (Rudershausen et al. 2015) found that rectangular mesh gillnets of different mesh sizes and depths reduced catches of unwanted fish including red drum Sciaenops ocellatus and undersized individuals of the commercial target species southern flounder Paralichthys lethostigma compared to conventional diamond mesh nets. Numbers of unwanted fish were lower in rectangular mesh nets than diamond mesh, irrespective of the depth profile (number of meshes) of the net (rectangle: 0.4–0.5 fish/90 m, square: 4.1–4.8 fish/90 m) and mesh size (rectangle: 0.4 fish/30 m, square: 1.2–1.4 fish/30 m). Red drum and undersized southern flounder catches were lower in rectangular than diamond meshes for both net depth profiles (red drum: 0.0 vs 0.2–0.3 fish/90 m; flounder: 0.0–0.1 vs 0.5 fish/90 m). Catches of both species were lower in rectangular nets compared to diamond mesh nets for two of three mesh size comparisons (14.0 and 15.2 cm mesh sizes for red drum and 14.6 and 15.2 cm for undersized flounder – see paper for data). Legal-sized catches of target flounder were similar in rectangular and diamond mesh nets for both low profile (0.9 vs 1.1) and high profile nets (0.4 vs 0.7/90 m), but lower in all three rectangular mesh sizes than corresponding diamond nets (14 cm: 0.2 vs 0.4, 14.6 cm: 0.3 vs 0.5, 15.2 cm: 0.1 vs 0.4/30 m). Experimental gillnet deployments were made in the Neuse River estuary in April–June 2010 and in the Newport River Estuary in April–October in 2011–2013. In 2010, paired deployments (85) of one of two rectangular mesh nets, 20 meshes (‘low profile’) and 33 meshes (‘high profile’) deep, and one diamond mesh gillnet (20 meshes deep), all 14 cm mesh size were made, set parallel to the shore for 12 h. In 2011–2013, a total of 150 paired deployments were made of three rectangular mesh nets and three diamond mesh nets of different mesh sizes (14.0 cm, 14.6 cm or 15.2 cm), set for 12 h parallel to shore.

    (Summarised by: Leo Clarke)

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