Study

Habitat use and the effect of shrimp trawling on fish and invertebrate communities over the northern Gulf of Mexico continental shelf

  • Published source details Wells R.J.D., Cowan J.H.J. & Patterson W.F.I. (2008) Habitat use and the effect of shrimp trawling on fish and invertebrate communities over the northern Gulf of Mexico continental shelf. ICES Journal of Marine Science, 65, 1610-1619.

Actions

This study is summarised as evidence for the following.

Action Category

Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor

Action Link
Marine Fish Conservation
  1. Cease or prohibit mobile fishing gears that catch bottom (demersal) species and are dragged across the seafloor

    A randomized, replicated, site comparison study in 2004–2005 on fishing grounds in the Gulf of Mexico, USA (Wells et al. 2008) found that areas not exposed to bottom trawling had different fish assemblages compared to trawled areas, and the effect on overall species diversity and richness (fish and invertebrates) and fish size, varied with the habitat type. Overall, the fish community structure for all three habitat types differed between non-trawled and trawled areas (reported as statistical results). Species diversity and richness (fish and invertebrates) differed between non-trawled and trawled areas on sand and shell habitats, but not reef, and were higher on non-trawled shell habitat but lower on non-trawled sand habitat. Average total length of four of the nine most important fish species (see paper for species individual data) was higher in non-trawled areas over sand habitat (non-trawled: 94–124 cm, trawled: 84–118 cm), and five were larger over shell (non-trawled: 114–254 cm, trawled: 91–239 cm). Data was collected quarterly in 2004 and 2005 by standard otter trawl net for groundfish surveys at three random stations over each habitat type (sand, shell and reef), both exposed and not exposed to bottom shrimp trawling (as determined from annual shrimp-trawling effort data). In non-trawled areas 24 deployments (10-minute tow) were done on sand, 48 on shell and 24 on reef. In trawled areas 21, 33 and 21 deployments were done on sand, shell and reef respectively. All fish (144 species) and invertebrates (70 species) caught were counted, weighed and fish lengths measured.

    (Summarised by: Ros McIntyre)

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