Aims Shellfish production areas are classified for suitability for human consumption using counts of Escherichia coli in shellfish samples. Two alternative laboratory methods are approved in the European Union and UK for measuring E. coli in shellfish samples; the most probable number (MPN) and pour plate methods. These methods have inherently different statistical uncertainty and may give different counts for the same sample. Using two approaches: simulated data and spiking experiments, we investigate the theoretical properties of the two methods to determine their reliability for shellfish waters classification.Methods and results Assuming a Poisson distribution of E. coli in shellfish samples, we simulate concentrations in 10 000 samples using the MPN and pour plate methods. We show that for higher concentrations of E. coli the pour plate method becomes increasingly more reliable than the MPN method. The MPN method has higher probabilities than pour plate of generating results exceeding shellfish classification thresholds, while conversely having higher probabilities of failing to detect counts that exceed regulatory thresholds. The theoretical analysis also demonstrates that the MPN method can produce genuine extreme outliers, even when E. coli are randomly distributed within the sampled material. A laboratory spiking experiment showed results consistent with the theoretical analysis, suggesting the Poisson assumption used in the theoretical analysis is reasonable.Conclusion The large differences in statistical properties between the pour plate and MPN methods should be taken into consideration in classifying shellfish beds, with the pour plate method being more reliable over the crucial range of E. coli concentrations used to determine class boundaries.

The short-beaked common dolphin is one of the most numerous cetacean species in the North-East Atlantic and plays a key functional role within the ecosystem as a top predator. However, in 2013, its conservation status for the European Marine Atlantic, under Article 17 of the Habitats Directive, was assessed as 'Unfavourable-Inadequate'. Of key concern for this species is fishery bycatch, with pollution also being an issue. There are, however, major knowledge gaps concerning the extent of the effects of such pressures on the species. Implementation of national observer bycatch programmes and bycatch mitigation measures under EC Regulation 812/2004 has been important. The responsibility for this is currently being transferred to the EU fisheries Data Collection Framework and Technical Measures Framework, the potential advantages and disadvantages of which are discussed. Collection of data and samples through national stranding schemes in some countries has enabled assessments of life-history parameters, dietary requirements, and the effects of stressors such as pollutants. Nevertheless, in order to improve the conservation status of the North-East Atlantic population, a number of key actions are still required. These include the implementation of a species action plan, finalization of a management framework procedure for bycatch, and coordination between member states of monitoring programmes. It is important that there is monitoring of the state of the common dolphin population in the North-East Atlantic management unit through regular surveys spanning the range of the management unit, as well as continued assessment of the independent and interactive effects of multiple stressors. Above all, conservation status would be improved through application and enforcement of existing legislation in European waters. This paper provides a summary of the current state of our knowledge of common dolphins in the North-East Atlantic along with recommendations for conservation management that may also be relevant to the species in the Mediterranean Sea.

Council Directive 92/43/EEC (OJ L 206/22.7.1992) on the conservation of natural habitats and of wild fauna and flora (EU Habitats Directive) represents one of the most important instruments ever introduced for nature conservation, and yet its application has led to a questioning of its value, particularly in relation to its perceived impact on business. This has been exacerbated by the legal approach to enforcement, which has not been examined through the lens of favourable conservation status (FCS) which is at the heart of the directive, but instead is dictated by lobbyists (e.g. the environmental non-governmental organisations (NGOs)), leading to a system focused on charismatic species and one where the best conservation tools can be ignored. In particular, this can be exemplified by the harbour porpoise, a European Protected Species and one for which Special Areas of Conservation (SACs) should be designated if suitable sites can be identified. Harbour porpoise are the smallest marine mammal in UK waters and are a highly mobile

Assessment of ecosystem health is required in the ecosystem approach to fisheries management (EAFM). Mitigation measures that address impacts exceeding the acceptable level also require assessment. The various fishing métiers have different ecosystem impacts and this makes it difficult to assess them jointly. Sensitivity of the ecosystem to individual fishing métiers has been assessed previously, but to our knowledge, concurrent comparisons of different métiers on the same ecosystem have not been done. In this study, we combined the main characteristics of established approaches to sensitivity assessment into a single roadmap, called Sensitivity Assessment of Gear Effects (SAGE). SAGE is a widely applicable, three-step process to assess the ecological concerns of EAFM. The methodology used in the SAGE roadmap is built on a scoring system, which then results in a sensitivity index of the ecosystem components to the fishing métiers. The scoring system is based on a combination of expert judgement and data, both qualitative and quantitative. It allows for cross-evaluation of fishing métiers and ecosystem components. Sensitivity maps are created using the spatial and temporal distribution patterns of the ecosystem components in the index. The uncertainty of the sensitivity scores and maps are estimated through a pedigree index. The index is based on proxy representation, empirical basis, methodological rigour, theoretical understanding and degree of validation, all of which measure the strength of the research results. The proposed methodology is illustrated using a case study that compares the ecosystem effects of beam trawl and trammel net fisheries. The selected examples did not result in unexpected outcomes, but were rather chosen to evaluate the applicability of our methodology. They illustrate how a semi-quantitative framework, which includes the uncertainties associated with scientific assessments, can deliver holistic advice to fisheries managers in a fully transparent manner.

On 9 June 2008, the UK's largest mass stranding event (MSE) of short-beaked common dolphins (Delphinus delphis) occurred in Falmouth Bay, Cornwall. At least 26 dolphins died, and a similar number was refloated/herded back to sea. On necropsy, all dolphins were in good nutritive status with empty stomachs and no evidence of known infectious disease or acute physical injury. Auditory tissues were grossly normal (26/26) but had microscopic haemorrhages (5/5) and mild otitis media (1/5) in the freshest cases. Five lactating adult dolphins, one immature male, and one immature female tested were free of harmful algal toxins and had low chemical pollutant levels. Pathological evidence of mud/seawater inhalation (11/26), local tide cycle, and the relative lack of renal myoglobinuria (26/26) suggested MSE onset on a rising tide between 06:30 and 08∶21 hrs (9 June). Potential causes excluded or considered highly unlikely included infectious disease, gas/fat embolism, boat strike, by-catch, predator attack, foraging unusually close to shore, chemical or algal toxin exposure, abnormal weather/climatic conditions, and high-intensity acoustic inputs from seismic airgun arrays or natural sources (e.g., earthquakes). International naval exercises did occur in close proximity to the MSE with the most intense part of the exercises (including mid-frequency sonars) occurring four days before the MSE and resuming with helicopter exercises on the morning of the MSE. The MSE may therefore have been a "two-stage process" where a group of normally pelagic dolphins entered Falmouth Bay and, after 3-4 days in/around the Bay, a second acoustic/disturbance event occurred causing them to strand en masse. This spatial and temporal association with the MSE, previous associations between naval activities and cetacean MSEs, and an absence of other identifiable factors known to cause cetacean MSEs, indicates naval activity to be the most probable cause of the Falmouth Bay MSE.

In the first seven months of 2008, eighteen Cuvier's beaked whales ( Ziphius cavirostris ), four Sowerby's beaked whales ( Mesoplodon bidens ), five unidentified beaked whales and twenty-nine long-finned pilot whales ( Globicephala melas ) were reported stranded in the UK and Ireland. Decomposition of those animals investigated puts the predicted time of death at mid-January. Concerns that an unusual mortality event had taken place prompted further investigations. Most carcasses were too decomposed for necropsy. A summary of findings is presented here. Although the initial stranding of five Cuvier's beaked whales in Scotland shared some similarities with atypical mass stranding events linked in time and space to mid-frequency naval sonars, there were two important differences with the remaining strandings during this period. First, the geographical range of the event was very wide and second, the strandings occurred over a prolonged period of several months. Both of these factors could be related to the fact that the mortalities occurred offshore and the carcasses drifted ashore. The cause(s) of this high number of strandings of mixed offshore cetacean species during this period remain undetermined.

Between 13 January and 14 April 2008, 14 Cuvier's beaked whales ( Ziphius cavirostris ), five Sowerby's beaked whales ( Mesoplodon bidens ), four unidentified beaked whales and 22 long-finned pilot whales (Globicephala melas ) were reported stranded in Scotland, Ireland and Wales. Concerns that an unusual mortality event had taken place prompted further investigations although most carcasses were deemed to be too decomposed for necropsy. Preliminary findings are presented here and some potential causes of death considered. Although the event had some similarities with atypical mass stranding events linked in time and space to mid frequency sonars, there were also two important differences. First, the geographic range of the event was very wide and second, the strandings occurred over a prolonged period of about three months. Both of these factors could be related to the fact that the mortalities occurred offshore and the carcasses drifted ashore. The cause(s) of these high number of offshore mixed-species cetacean strandings during this period remains undetermined at this time.

Blooms of macroalgal matting are increasingly common within temperate zones and are often comprised of opportunistic species such as Ulva lactuca. Where this algae forms a dense mat, a stressful environment is created in the sediment below, influencing the invertebrate infaunal assemblage. This study was conducted over a six month period during which a dense mat of U. lactuca developed and subsequently dispersed. The algal mat was found to have a significant negative impact on species richness, abundance and biomass of the macroinfauna. However, a faunal community developed within the algal mat which contained several species not previously observed. This community increased the abundance and diversity of the overall invertebrate assemblage. The results are discussed in relation to impacts on the ecosystem as a whole.

Blooms of macroalgal matting, comprising opportunistic species such as Ulva lactuca, are becoming increasingly common in Poole Harbour. A hostile environment is usually created in the sediment below a dense algal mat, influencing the invertebrate faunal assemblage. This preliminary study was conducted over a 6 month period during which a dense mat of U. lactuca developed and subsequently dispersed in Holes Bay. The algal mat was found to have a significant negative impact on species richness, abundance and biomass of the infauna. The results are discussed in relation to impacts on the ecosystem as a whole.

Awareness of the ecosystem effects of fishing activities on the marine environment means that there is a vital need to assess the direct and indirect effects of those activities that may have negative effects on target and non-target species. The Edible Cockle Cerastoderma edule is the target of an artisanal and commercial fishery that occurs in estuarine and intertidal habitats across northern Europe. Poole Harbour has opened up its cockle beds to pump-scoop dredging over the last few years. This study investigated the effect of pump-scoop dredging on the intertidal sedimentary environment and the macro-infaunal community. The results demonstrated that the dredging did not have an effect on the size distribution of sediment particles. After the fishery opened, no immediate impact of cockle dredging on the infaunal community was observed. Within 3 months, however, a reduction in species richness and abundance of the benthic community was noted. This may be indicative of a chronic rather than acute impact. However, further investigations are required to assess whether this was directly related to pump-scoop dredging. The findings of this study are discussed in relation to possible impacts on the ecosystem as a whole.

This study investigates the effect of an introduced species, Sika Deer Cervus nippon on saltmarsh plant and infaunal communities. Epidermal fragment analysis was used to identify the plant species eaten by Sika Deer. Vegetation communities in deer exclosures and openly grazed areas were monitored over 4 years to investigate the effect of grazing on plant community composition and structure. The infaunal communities were assessed by extracting sediment cores. Deer were found to graze preferentially on Spartina anglica as intensive grazing led to swards dominated by Salicornia ramosissima even in upper marsh areas. Highest plant diversity was related to intermediate levels of grazing. Overall, higher levels of grazing led to higher abundance of three species of infauna detected in this study: Hydrobia ulvae, Gammarus sp. and Nereis diversicolor. Detailed examination revealed that the high abundance of H. ulvae was related to small quantities of above ground vegetation volume and that the abundance of Gammarus was related to small quantities of below ground vegetation biomass. The possible direct and indirect effects of Sika Deer grazing on bird populations are discussed.