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Providing evidence to improve practice

Individual study: Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling

Published source details

Koslow J., Gowlett-Holmes K., Lowry J., O'Hara T., Poore G. & Williams A. (2001) Seamount benthic macrofauna off southern Tasmania: community structure and impacts of trawling. Marine Ecology Progress Series, 213, 111-125

This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Designate a Marine Protected Area and prohibit bottom trawling Subtidal Benthic Invertebrate Conservation

A replicated, site comparison study in 1997 of 14 seamounts south of Tasmania, South Pacific Ocean, Australia (Koslow et al. 2001) found that seamounts within a protected area closed to trawling tended to have different invertebrate community composition, more species and higher biomass of invertebrates, compared to shallow unprotected seamounts, but not compared to deep unprotected seamounts, after two years. Results were not tested for statistical significance. Invertebrate community composition appeared typically similar at protected seamounts and deep unprotected seamounts, but different to that of shallow unprotected seamounts (data presented as graphical analyses). Protected seamounts tended to have more invertebrate species (22 species/sample) and biomass (6 kg/sample) compared to shallow unprotected seamounts (9 species/sample; 1 kg/sample) and similar to deep unprotected seamounts (20 species/samples; 7 kg/sample). The low diversity and biomass at shallow unprotected were associated with the loss of coral substrate from intense trawling. In 1995, a protected area was established and closed to trawling. In 1997, invertebrates (including corals) (>25 mm) living on the seamounts inside (6 seamounts; 12 samples) and outside (8 seamounts; 22 samples) the protected area (peaks at approximately 660–1,700 m depths) were sampled using a dredge. Invertebrates were sorted into groups and weighed by groups. Shallow unprotected seamounts were heavily fished, but deep seamounts were only lightly fished.

(Summarised by Anaëlle Lemasson)