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Providing evidence to improve practice

Individual study: Impact of scallop dredging on benthic epifauna in a mixed-substrate habitat

Published source details

Boulcott P., Millar C.P. & Fryer R.J. (2014) Impact of scallop dredging on benthic epifauna in a mixed-substrate habitat. ICES Journal of Marine Science, 71, 834-844


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 dredging Subtidal Benthic Invertebrate Conservation

A paired, replicated, site comparison study in 2009 of nine sites in three areas of sandy and rocky seabed in the Firth of Lorn, Scotland, UK (Boulcott et al. 2014) found that sites inside a protected area that had been prohibiting dredging for approximately 2.5 years typically had greater combined cover of bryozoans and hydroids and different combined invertebrate and fish community composition compared to unprotected dredged sites. In four of six comparisons, sites inside the protected area had higher cover of bryozoans and hydroids compared to dredged sites outside (inside 43 vs outside 34%; 25 vs 15%; 21 vs 10%; 22 vs 9%). In two comparisons, cover was similar inside and outside (19 vs 14%; 52 vs 54%). Community composition varied across the three areas, but within each area was always different in the protected and dredged sites (data presented as graphical analyses). Part of the Firth of Lorn was designated as a Special Area of Conservation in March 2005 and closed to scallop dredging in the boreal spring of 2007. Three areas (25–89 m depth) along the boundary of the closed area were selected. In each area, one site on each side of the boundary (i.e. one inside the closed area, one outside) was surveyed in May and again in July–August 2009. Invertebrates were surveyed using a camera at 30–40 sampling stations/area. For three photographs/station/survey, the combined area covered by erect bryozoans and hydroids was measured, and all animals (24 invertebrate species; combined with one species of skate and one group of fish species) identified and counted.

(Summarised by Anaëlle Lemasson & Laura Pettit)