Publication Abstract

Small-scale heterogeniety in the mobile macro-epifauna associated with mud, sand and coarse habitats

J.R. Ellis, T. Maxwell, M. Schratzberger, K. Warr and  S.I. Rogers

In recent years, several studies have utilised groundfish surveys as sampling platforms for the broadscale examination of epibenthic fauna. Several fisheries laboratories utilise a 2m steel beam trawl with chain mat for the sampling of epifauna, although only single samples are usually collected at the sampling stations. Hence, although such surveys provide valuable information on the broadscale distribution of epibenthic assemblages, their utility for examining issues relating to species diversity may be restricted by lack of replication. Intensive replicate sampling with 2m beam trawl has now been conducted on specific offshore biotopes around the British Isles, including two mud biotopes (Celtic Deep and north-western Irish Sea), three sand biotopes (outer Bristol Channel and inner and outer Carmarthen Bay), two sand banks (Swarte and Broken Banks in the southern North Sea) and two coarse grounds (a gravel bed in the North Sea and a shell-gravel habitat in the western English Channel). For most sample sites, sampling involved five replicate tows at a central station with single tows taken at eight surrounding grid stations (2 nm and 6 nm NW, NE, SW and SE of the central station). The similarities between catches at these stations and the cumulative number of species observed are described, with the implications for the resource required for monitoring diversity on offshore grounds discussed.

Reference

J.R. Ellis, T. Maxwell, M. Schratzberger, K. Warr and S.I. Rogers (2007) Small-scale heterogeneity in the mobile macro-epifauna associated with mud, sand and coarse habitats. ICES CM 2007/A: