An examination of chronic trawling effects on soft-bottom benthos of the eastern Bering Sea

Published source details McConnaughey R. (2000) An examination of chronic trawling effects on soft-bottom benthos of the eastern Bering Sea. ICES Journal of Marine Science, 57, 1377-1388.
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This study is summarised as evidence for the following.

	Action	Category
	Cease or prohibit bottom trawling Action Link

Cease or prohibit bottom trawling

A paired site comparison study in 1996 of 84 sites of sandy seabed in the eastern Bering Sea, USA (McConnaughey et al. 2000) found that ‘macro’-invertebrate (size unspecified) species diversity and abundance were higher in sites closed to trawling for 37 years, compared to trawled sites, but there was no difference in biomass. Overall across paired sites, species diversity was higher in sites closed to trawling compared to those trawled (reported as a diversity index). Of the 42 invertebrate taxa recorded, 27 appeared more abundant in the closed sites compared to the trawled sites (not statistically tested). In particular, abundances of sponge (Porifera), anemones (Actinaria) and Neptunea snails (gastropods) were significantly higher in the closed sites (data not shown). Invertebrate biomass was similar in sites closed to trawling (1.6 kg/ha) and trawled sites (1.6 kg/ha). Trawling was prohibited in an area in 1959. Macro-invertebrates were surveyed at 84 sampling sites (44–55 m depth) along the boundary of the closed area (42 pairs; one site on either side of the boundary, 1 nm apart) using an otter trawl (3.8 cm liner at the codend). Macro-invertebrates were sorted into groups, counted and weighed.

(Summarised by: Anaëlle Lemasson)