Description: In 1996, a Russian expedition of the RV "Professor Logachev" acomplished a firstdescription of habitats at the Håkon Mosby Mud Volcano (HMMV) using deep-towphotography and video imagery. Apart from Pogonophora and bacterial mats, Lycodes squamiventer constituted the most abundant fauna at HMMV. Here, we use advanced techniques of the Victor 6000 system to describe habitats along transects and estimate the abundance of demersal fish in different habitats. The aim of this study was to determine possible fish-habitat associations. Preliminary analyses indicated that fish densities are highest in a habitat characterized by mud and ripples. The highest Lycodes densities were recorded at the centre of the volcano and in an area south of the centre. Further conclusions can be drawn by overlaying fish abundance with environmental data (e.g. sedimentology, habitat, and micro-bathymetry).

Description: 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 sixsandbanks 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 distinctfrom those sandbanks considered to be extensions of nearshore sediments. The distinct sandbanks were typified by low speciesdiversity and shared indicator species such as the weever fish Echiichthys vipera, the shrimp Philocheras trispinosus and the hermitcrab Pagurus bernhardus. Differences occurred in species composition among the distinct sandbanks, in particular, southernsandbanks were typified by sand sole Solea lascaris and small-eyed ray Raja microocellata. The sandbanks considered as extensionsof nearshore sediments shared many similarities with the Pleuronectes platessaLimanda 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 EUhabitats directive, are likely to incorporate a number of physically and biologically distinct habitats of which two have beendescribed in the present study.

Description: Demersal fisheries generate large quantities of unwanted by-catch. Nephrops norvegicus is the most important shellfish resource in UK waters and although the fishing effort has increased considerably over past decades the ecological effects of this fishery have yet to be evaluated. This study provides a baseline assessment of the composition and fate of invertebrates regularly discarded in the Clyde Nephrops fishery. Monthly sampling on local fishing boats revealed that only 18% of the catch is landed, invertebrates accounting for up to 90% of the discards. Crustaceans (Liocarcinus depurator, Munida rugosa) and echinoderms (Asterias rubens, Ophiura ophiura) were the most important groups discarded. Monthly damage assessments of invertebrates collected from commercial trawlers showed the severity and frequency of damage was mainly correlated with species-specific morphological and behavioural characteristics: almost all O. ophiura and some 40%-60% of the crustaceans incurred injury. By contrast, damage was low in more flexible invertebrates such as A. rubens (30%) or hard-shelled animals such as Pagurus bernhardus (14%) and Aequipecten opercularis (2%). Biochemical analyses of haemolymph samples taken from trawled and emersed crustaceans revealed significant increases in ammonia, glucose and lactate concentrations along with a decrease in pH. Recovery started after 4 h. Longer-term survival experiments showed that post-trawling mortality was 100% for O. ophiura 14 d after trawling; by contrast, almost all hermit crabs and whelks survived. Experimental ablation of appendages and autotomy increased L. depurator post-trawling mortality significantly (78% and 26%) cf. creel-caught controls (8%). Asterias rubens with multiple arm loss showed 〉90% mortality 21 d after trawling possibly due to an increased risk of infection with Vibrio metschnikovii. While mortality figures for most species doubled over the last 14 d of the experiment, most previous studies covered monitoring periods of only 〈5 d and may have underestimated discard mortality. Traps baited with crustacean and echinoderm discards deployed at sea attracted a number of species. While whelks and A. rubens were found in significantly higher numbers in traps baited with crustaceans, P. bernhardus was more attracted to A. rubens bait. The two amphipods Orchomene nanus and Scopelocheirus hopei occurred in high numbers (n=2745) and preferred traps baited with crustaceans. These findings are discussed with respect to their ecological significance and relevance to fisheries management.

Description: There is a pressing need to identify the characteristics of habitats that have an important or 'essential' functional role for particular species or type e.g. piscivores/herbivores/omnivores or flatfish/roundfish. Identifying such habitat characteristics and quantifying the spatial extent of fish habitat resources is fundamental to the successful management of these habitats and species. No general methodology has yet been developed to describe which elements might constitute an essential fish habitat. The acoustics ground-discrimination system QTC was used to identify the linkage between epibenthic and demersal fish assemblages and their species to provide a remote means to infer important habitat features appropriate for their delineation.A strong correlation with the acoustic seabed properties of this classification system was found. Eight different study sites, selected for their differences in demersal fish abundance, were sampled using a 3-m and 2-m beam trawl in the Irish Sea. Multivariate analyses were used to identify benthic and fish assemblage structure, and to characterise their habitats. Distinct benthic and fish assemblages were associated with statistically different seabed classification data derived from QTC. These were in turn strongly, although not exclusively, associated with changes in water depth. Fish assemblages showed a stronger correlation with acoustic classifications than epibenthos, indicating that QTC provides a robust method for seabed classification and mapping of fish habitats.

Description: Despite over a century of exploitation of fish in European waters, scientists know surprisingly little about the precise distribution of the major commercially exploited fish species, and their habitat requirements. This is the first European study that aims to identify essential fish habitats of commercially important fish species (cod, haddock, whiting, plaice, sole, plaice, lemon sole) in the Irish Sea and the English Channel (UK). Areas of the seabed that harbour the highest densities of these species were identified and mapped using an existing database spanning 12 years data from national stock assessments. Demersal fishers observe samples from the sea floor every time they haul their nets, which far exceed the sampling schemes that scientists can afford or mobilise. Experienced fishers may have decades of observations to bring to bear and keep detailed records of exactly where and when they fish and how much they catch. Although the ultimate goal of fishing is to provide income from the catch, rather than to test scientific hypotheses, many fishers seek to understand the very questions about the seabed that motivate our study. Therefore, we decided to liase with the fishing industry to refine our broad scale fish maps for future survey. Information was gathered in a pilot study through questionnaires filled in at a fishing exhibition. Through a process of informal presentations and meetings, fishermen have helped us to refine our studies by pinpointing fishing grounds of importance for the fish species in question. The co-operation with fishers has not only added to the credibility of the study and any management decisions that may depend on its findings, but has also highlighted once more the vast amount of knowledge that can be gained from this declining species.