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.

Cross-community congruence of patterns in a marine ecosystem: Do the parts reflect the whole?

“…Olsgard & Somerfield (2000) and Olsgard et al (2003) have tested the potential for using 'sub-community' surrogates such as polychaetes to assess the overall diversity and community structure of the macrobenthos. In a few more cases, more than one marine community has been studied and results have been compared (Warwick & Clarke 1991, Callaway et al 2002, Lovell & Trego 2003, Hillebrand 2004, Irigoien et al 2004, Kaiser et al 2004) in the particular context of each paper. However, it is still unknown whether a wide range of marine communities from infaunal invertebrates to demersal fish and plankton organisms, co-occurring in space and time, interacting in various ways and at various levels, depending on the same primary production and subject to varying degrees to local disturbance provide similar or different patterns in community structure and species diversity.…”

Diversity and composition of macrobenthic community associated with sandy shoals of the Louisiana continental shelf

“…More generally, shoals exhibit a unique physical regime, leading to special hydrodynamic and sedimentary patterns and to distinct species assemblages. But the extent to which associated fauna is distinct from surrounding environments is poorly known (Kaiser et al 2004). A significant number of species not reported previously for the Louisiana continental shelf were found on Ship Shoal.…”

“…Sabine and Healds Shoals) have been recently investigated (Cheung et al 2006) but these studies and a recent macrobenthic survey of Louisiana in-shore and off-shore waters (Baustian 2005) did not include Ship Shoal, partly because its shallow depth has discouraged access by large research vessels. A habitat specific survey of the epifauna and fish fauna of several sandbanks off the Welsh coast (UK) revealed that sandbanks were characterized by a unique (although low diverse) epifauna and fish assemblages (Kaiser et al 2004). But the authors also stated that sandbanks are difficult habitats to sample and may have been overlooked by biologists.…”

Advanced Spatial Modeling to Inform Management of Data-Poor Juvenile and Adult Female Rays

“…We know these species are mobile enough within the Irish Sea to mix into and out of refugia rather than being extirpated in fine spatial scales [3,5,8,38]. Before implementing spatial management based on this method, one should ground-truth such areas with directed sampling trips [39,40], incorporate additional datasets where possible (e.g., from the catch and discard observer program), or use manual testing/training splits to test predictive power.…”

“…The Irish Sea is a shallow-shelf sea with a 100 m-deep Central Channel and very shallow (≤5 m) sandbanks running along the Western edge (Irish coast), which create deeper channels 7-12 km from shore [24,63,64]. Surveyed CPUE of rays in the Irish Sea show correlations with depth, substrate, temperature, salinity, current speed and distance to shore [11,38,68,69]. Neither standard linear correlations nor GAMs (conducted on these data in previous studies [11]) revealed stronger relationships between survey CPUE and any specific month of environmental variable data.…”