Demersal fish and epifauna associated with sandbank habitats

Abstract

A habitat specific survey of the epifauna and fish fauna of sandbanks off the Welsh coastline was undertaken in 2001. Of these, three sandbanks were considered to represent extensions of shallow nearshore soft-sediment communities, while a further six sandbanks were considered to be distinct sandbanks; seabed features clearly defined in comparison with surrounding sediments. Multivariate community analyses revealed that the distinct sandbanks had both fish and epifaunal assemblages that were distinct from those sandbanks considered to be extensions of nearshore sediments. The distinct sandbanks were typified by low species diversity and shared indicator species such as the weever fish Echiichthys vipera, the shrimp Philocheras trispinosus and the hermit crab Pagurus bernhardus. Differences occurred in species composition among the distinct sandbanks, in particular, southern sandbanks were typified by sand sole Solea lascaris and small-eyed ray Raja microocellata. The sandbanks considered as extensions of nearshore sediments shared many similarities with the Pleuronectes platessa– Limanda limanda assemblage, identified by Ellis et al. (Estuar. Coastal Shelf Sci. 51 (2000) 299), which is widespread in the Irish Sea. Sandbanks, as a habitat definition under the EU habitats directive, are likely to incorporate a number of physically and biologically distinct habitats of which two have been described in the present study.