We examined the effects of fishing with crustacean traps on benthic species in Great Britain by means of qualitative and quantitative experiments. Experimental sites were selected where fishing using pots or creels was practised regularly and where species perceived to be potentially sensitive to damage were present. The effect of Nephrops creels on different sea pen species was studied in Scottish sea lochs. Sea pens were observed to bend in response to the pressure wave before the creel made contact. After smothering and even uprooting, they re-established themselves when in contact with muddy substrate. Observations of lobster and crab pots being hauled from rocky substrates in southern England, revealed that the habitats and their communities appeared relatively unaffected by potting. The slow-growing, long-lived, pink sea fan Eunicella verrucosa were observed to flex under the weight of pots as they passed and then returned back to an upright position. Quantitative studies, undertaken in south England and west Wales, were based on surveys carried out along transect lines before and after a month of pot fishing for crabs and lobsters. The results suggest that four weeks of fairly intense fishing did not have immediate detrimental effects on the abundance of the species selected for study, although some individual ross coral colonies (Pentapora foliacea) were damaged.

Aquaculture is currently the fastest expanding global animal food production sector and is a key future contributor to food security. An increase in food security will , 2015, 16, 668-683 be dependent upon the development and improvement of sustainable practices. A prioritization exercise was undertaken, focusing on the future knowledge needs to underpin UK sustainable aquaculture (both domestic and imported products) using a 'task force' group of 36 'practitioners' and 12 'research scientists' who have an active interest in sustainable aquaculture. A long list of 264 knowledge needs related to sustainable aquaculture was developed in conjunction with the task force. The long list was further refined through a three stage process of voting and scoring, including discussions of each knowledge need. The top 25 knowledge needs are presented, as scored separately by 'practitioners' or 'research scientists'. There was similar agreement in priorities identified by these two groups. The priority knowledge needs will provide guidance to structure ongoing work to make science accessible to practitioners and help to prioritize future science policy needs and funding. The process of knowledge exchange, and the mechanisms by which this can be achieved, effectively emerged as the top priority for sustainable aquaculture. Viable alternatives to wild fish-based aquaculture feeds, resource constraints that will potentially limit expansion of aquaculture, sustainable offshore aquaculture and the treatment of sea lice also emerged as strong priorities.Although the exercise was focused on UK needs for sustainable aquaculture, many of the emergent issues are considered to have global application.

1. The occurrence of non‐native marine macro fauna and flora, which have become established in the wild British waters, are summarized. The effects of these non‐natives on the native fauna and flora and on commercial and recreational interests are reviewed.  2. Sixteen species of marine algae (11 rhodophytes, three chromophytes and two chlorophytes), five diatoms, one angiosperm and 31 invertebrates were identified as non‐native. The majority of these species are red algae, polychaete worms, crustaceans and molluscs.  3. Species were introduced directly from primary sources within their natural range, or from secondary sources to which they had previously been introduced. They have only become established where introduced from similar latitudes of both hemispheres.  4. More than half the total number of species are considered to have been introduced to Britain in association with shipping, whilst half of the non‐native marine algae are believed to have been introduced in association with deliberate introductions for mariculture.  5. Of the species that had spread, the marine plants did so fairly rapidly, while the invertebrates tended to spread more slowly. The methods of spread were often the same as their method of introduction for both flora and fauna.  6. The direct effects of non‐native species on the marine environment in British waters are not as detrimental as those reported from elsewhere in the world. Some commercially important species have been introduced, but some associated pests and parasites have accompanied them.  7. Control methods, where applied to populations of nuisance species, are fairly ineffective and no non‐native marine species have been deliberately eradicated from British waters. Ways of avoiding introduction of further non‐natives by mandatory and voluntary means are discussed. ©1996 by John Wiley & Sons, Ltd.

In the Welsh part of the Irish Sea, a method was developed for assessing the sensitivity of different seabed habitats to existing fishing activities, across a range of potential fishing intensities. The resistance of 31 habitats and their associated biological assemblage to damage by 14 categories of fishing activity were assessed along with the rate at which each habitat would recover following impact (resilience). Sensitivity was scored based on a combination of the resistance of a habitat to damage and its subsequent rate of recovery. The assessments were based, wherever possible, on scientific literature, with expert judgement used to extrapolate results to habitat and gear combinations not directly examined in the published literature. The resulting sensitivity matrices were then subject to further peer review at a series of workshops. Following consensus on the habitat sensitivity, these data were combined with the most resolved sea-floor habitat maps. These habitat sensitivity maps can help inform the development of site-specific management plans, as well as having a place in spatial planning and aiding managers in developing dialogue with other stakeholders. A case study of their application is provided.

1. Preliminary estimates of the relative sensitivity of sea bed types and benthic species to physical disturbance, particularly fishing activity, have been made in order to identify areas where further studies are required and to help formulate management plans for sites of marine conservation importance.  2. Physical disturbance is considered in the context of a single encounter with fishing gear followed by a recovery period during which there is no fishing, but with a view to qualifying, in the future, the effect of multiple fishing events. Disturbance is considered in terms of the physical action of the gear on the sea bed and the unit area over which this action occurs.  3. The effects of a wide range of gears are considered. Static gears, which can be employed on a variety of substrata, generally result in low level impacts for single fishing events and impacts are localized compared with the effects of mobile gears, which can extend over considerable areas.  4. The theoretical sensitivity of individual species is assessed on the basis of how well they cope with an encounter with fishing gear and on their likely recovery from destruction in terms of their reproductive strategies.  5. Species considered of key importance in the structuring of communities are suggested and examples of particularly sensitive species, which are therefore likely indicator species of physical disturbance, are listed.  6. Fragile, slow recruiting animals are considered to be most susceptible to disturbance, while the least sensitive species are generally fast growing and have good recruitment. ©1996 by John Wiley & Sons, Ltd.