For outbreaks of gastrointestinal disease, rapid identification of the source is crucial to enable public health intervention and prevent further cases. Outbreak investigation comprises analyses of exposure information from cases and, if required, undertaking analytical epidemiological studies. Hypothesis generation has been reliant on empirical knowledge of exposures historically associated with a given pathogen. Epidemiology studies are resource-intensive and prone to bias, one of the reasons being the difficulties in recruiting appropriate controls. For this paper, the information from cases was compared against pre-defined background exposure information. As exemplars, three past outbreaks were used, one of common and two of rare exposures. Information from historical case trawling questionnaires was used to define background exposure having removed any exposures implicated with the outbreak. The case-background approach showed good sensitivity and specificity, identifying correctly all outbreak-related exposures. One additional exposure related to a retailer was identified and four food items where all cases had been exposed. In conclusion, the case-background method, a development of the case-case design, can be used to assist with hypothesis generation or when a case-control study may not be possible to carry out.

The Bay of Málaga is located in a high biodiversity and productivity area that harbours a wide variety of commercial species exploited by different fishing fleets. Benthic and demersal fauna from circalittoral soft bottoms have been studied using a benthic dredge (BD) (8 sampling stations) and an otter trawl (OT) (8 sampling stations on a seasonal basis). Some sediment and water column variables, as well as the trawling activity, have also been studied and used for analysing their linkage with the fauna. A total of 287 species have been found in these bottoms and fish, molluscs and crustaceans represented the most diverse and abundant faunistic groups. A new record of the decapod Hippolyte leptometrae for Spanish waters is also included in this study. Some multivariate analyses using BD samples indicated the presence of three assemblages, but these seem to represent different facies of a single benthic community due to the absence of acute sediment changes and significant differences in the fauna. OT samples only displayed differences related to seasons but not to sediment types or depth. These seasonal differences seem to be linked to biological and ecological features of both dominant and/or commercial species. Mud and organic matter contents (%OM) in sediment, as well as the temperature, were the main variables linked to the spatial distribution of the benthic community identified with BD, whereas medium and coarse sand as well as gravel contents were the main variables linked to the changes of the epibenthic and demersal assemblage resulting from OT samples. The information of this study is of importance for improving the knowledge on the biodiversity of circalittoral soft bottoms of the Mediterranean and Alboran Sea as well as for the potential creation of a Marine Fisheries Reserve in the Bay of Málaga.

Benthic habitat and epibenthic megafauna are described from seabed photographs taken in or near three potential deep-water Marine Protected Areas on the Hebridean Slope, surveyed in 1988, 1995–96 and 1998. Broad bathymetric zones are defined by visible substratum characteristics, and by cluster analysis using presence/absence of identified fauna. The shelf edge and upper slope (to 350 m depth) showed current-swept coarse substrata with a very sparse fauna. A transition to finer sandy sediments was apparent at 350–470 m, with a greater abundance of mobile epifauna. The brittlestar Ophiocten gracilis occurred at high density below 600 m depth in all three areas. Southern stations indicated an abrupt lower boundary for this zone at ca 1000 m. In the north, rippled sands with xenophyophores occurred below the O. gracilis zone at 1000–1100 m. Xenophyophores were also seen in smaller numbers at this depth in the south. From ~1300–1600 m a seabed of burrowed fine mud was recorded in both northern and southern areas. Bioturbated sediments on the Rockall Trough floor at ~2060 m supported more visible epifauna, principally the brittlestar Ophiomusium lymani and the octocoral Acanella arbuscula. The bathymetric pattern differs from a scheme proposed in 2010 for the deep north-east Atlantic in the lack of any obvious zonal boundary at 750 m. No cold-water corals or sponge aggregations were observed. Trawl marks were observed in all three areas, particularly in the 1998 northern survey, with highest frequency at 1300–1400 m.

Beaked redfish inhabits North Atlantic waters in the depth range 100–950 m, over thecontinental shelf, slope and the open ocean. Individuals can live demersal or pelagic, atvarious stages of their life cycle. The geographical distribution of the species extendsto most of the Atlantic waters from Newfoundland and the Labrador basin in the west to theBarents Sea in the east. Monitoring beaked redfish is challenging because of the specieswide geographical distribution and large scale migrations; deep distribution, whichcomplicates trawling and hydroacoustic surveys; difficulties with tagging; and persistentdifficulties in taxonomic identification. These challenges make it a particularlyproblematic species to observe with conventional research methods. We review these keychallenges and provide recommendations for the coordinated observation of Sebastesmentella in the North Atlantic that would best contribute to the assessment andecological research on this species.

Mediterranean demersal fisheries have experienced an ongoing decline in catches over the past 20 years as a result of excessive increases in effort caused both by growth in trawler engine power and by rapid technological advances in fish finding and fishing technology. This has led to an overexploitation of these resources. An increasing share of the catches consists of immature individuals. This study was undertaken to test a sorting grid with a bar spacing of 20 mm as a means of excluding juveniles in the commercial hake (Merluccius merluccius) fishery in the Catalan Sea, western Mediterranean. The grid was placed in the extension section of the gear 5 m in front of a cod-end. Divided cod-end design was used to collect the escapees and target species. The mean selection length (L50) of the ten hauls was 14.2 ± 0.7 cm SE, with a selection range of 7.3 cm ± 0.4 SE. The biomass of hake under L50 that escaped through the grid represented 50.1% ± 6.7 SE of the total hake biomass. These results are promising and indicate that a sorting grid can be used in excluding young hake. This was a first step toward implementation of sorting grids in commercial trawl gears as means of avoiding unwanted catches of small individuals in the hake fisheries in the Mediterranean Sea. Further trials are required to improve the sorting efficiency of the grid.

Nephrops norvegicus (Norway lobster or prawn) is an important target species in demersal fisheries of the north-east Atlantic. Trawling for Nephrops is wasteful when many small fish are caught and discarded in the process. Here, data from 106 commercial fishing trips, sampled between 1982 and 1998 as part of the Scottish discard sampling programme, are used to investigate the fish bycatch and discards of Nephrops trawlers in the Firth of Clyde (west of Scotland). A large proportion of the fish caught in the Clyde is discarded, the discards mainly consisting of small demersal fish (mean length about 19 cm), particularly young whiting (Merlangius merlangus). Within the study period, annual estimates of total fish discards ranged from 318 to 3027 tonnes, with a mean of 1761 tonnes. Fish landings and discards biomass per unit effort both decreased over the study period. However, the decline in landings per unit effort was greater than that in discards per unit effort, corresponding to an increase in the discard rate over time. In recent years, discards have comprised about 70 % of the fish bycatch. The mean length of discarded fish was positively related to mesh size.