Le Quesne, W. J. F., and Codling, E. A. 2009. Managing mobile species with MPAs: the effects of mobility, larval dispersal, and fishing mortality on closure size. – ICES Journal of Marine Science, 66: 122–131. The use of closed areas (marine protected areas, marine reserves, no-take zones) has been suggested as a possible solution to the perceived global fisheries crisis. However, to optimize the design and evaluate the effectiveness of closed areas, we need to understand the interaction between larval dispersal, adult mobility, and fishing mortality. In this paper, a simple, spatially explicit dynamic population model was developed to examine the effects of these interacting factors on optimal closure size and resulting yields. The effect of using one large or several smaller closed areas was also examined. Our model confirmed previous results: closed areas do not improve the yield of populations that are optimally managed or underexploited and, as mobility increases, optimum closure size increases. The model also predicted some interesting counter-intuitive results; for overexploited stocks, the greatest benefit from closed areas can be obtained for stocks with highest mobility, although this may require closure of 85% of the total area. For the tested parameter settings, adult spillover had greater potential to improve yield than larval export, and using several small closed areas rather than a single larger one had the same effect as increasing the mobility of the population.

Summary: 1. Large‐bodied species are especially vulnerable to fishing in mixed fisheries. Their effective conservation requires predictions of sensitivity and exposure to fishing mortality, but such predictions are hard to make when the population dynamics of most of these species have not been described.2. We present a method for assessing sensitivity and conservation management reference points using widely available life‐history data. The method allows the sensitivity of all fish species in a community to be assessed in relation to conservation‐ and yield‐based fishery reference points.3. Knowledge of sensitivity is used to (i) rank species by sensitivity, (ii) conduct a risk assessment to identify species potentially vulnerable to current fishing pressure and (iii) examine potential trade‐offs between fishery catches and the conservation status of sensitive species.4. The method is applied to the Celtic Sea bottom‐dwelling fish community. For the species present, conservation threshold fishing mortalities ranged from 0·05 per year for the most sensitive large elasmobranchs to over 1 per year for small teleosts. The assessment predicts that current levels of fishing mortality may place all the elasmobranchs and over a quarter of the teleosts below conservation reference points.5. Depending on the relative mortality rates affecting commercially targeted species and species of conservation concern, up to 65% of the potential yield‐per‐recruit of commercially important species may have to be forgone to reduce fishing mortality below conservation limit reference points for the most sensitive species.6. Synthesis and applications.The method presented provides a clear objective procedure to construct ranked species sensitivity lists that can inform management, monitoring and research. The Celtic Sea case study demonstrated that limiting fishing pressure on key commercial stocks to meet fisheries production targets may be insufficient to guarantee the persistence of more sensitive species. Management actions that effectively decouple the mortality rates on commercial species and ‘conservation’ species are likely to be required to make progress in relation to conservation objectives. The method would support rapid assessment of sensitivity to fishing in many regions around the world as only taxonomic lists and estimates of body size are required.

The Regional Organization for the Protection of the Marine Environment (ROPME) Sea Area (RSA) in the northern Indian Ocean, which comprises the Gulf, the Gulf of Oman and the northern Arabian Sea, already experiences naturally extreme environmental conditions and incorporates one of the world’s warmest seas. There is growing evidence that climate change is already affecting the environmental conditions of the RSA, in areas including sea temperature, salinity, dissolved oxygen, pH, and sea level, which are set to continue changing over time. The cumulative impacts of these changes on coastal and marine ecosystems and dependent societies are less well documented, but are likely to be significant, especially in the context of other human stressors. This review represents the first regional synthesis of observed and predicted climate change impacts on marine and coastal ecosystems across the ROPME Sea Area and their implications for dependent societies. Climate-driven ecological changes include loss of coral reefs due to bleaching and the decline of fish populations, while socio-economic impacts include physical impacts from sea-level rise and cyclones, risk to commercial wild capture fisheries, disruption to desalination systems and loss of tourism. The compilation of this review is aimed to support the development of targeted adaptation actions and to direct future research within the RSA.

The development of desalination has been essential to the rapid economic development of the countries bordering the Arabian Gulf. The current production capacity of sea water desalination plants drawing water from Gulf is over 20 million m³ day^-1, which may rise to 80 million m³ day^-1 by 2050. Whilst supporting aspects of sustainable development related to water and sanitation, desalination impacts the marine environment through impingement and entrainment of organisms in intakes, and through thermal, brine and chemical discharges. This may compromise other objectives for sustainable development related to sustainable use of the oceans. Under business as usual scenarios, by 2050, the impact of individual desalination plants will combine causing a regional scale impact. Without mitigating actions to avoid the business as usual scenario, by 2050, desalination in combination with climate change, will elevate coastal water temperatures across more than 50% of the Gulf by at least 3 °C, and a volume of water equivalent to more than a third of the total volume of water between 0 and 10 m deep will pass through desalination plants each year. This will adversely impact the coastal ecosystem of the Gulf, with impacts on biodiversity, fisheries and coastal communities and may cause potential loss of species and habitats from the Gulf. Given the significant implications of these preliminary findings, and in light of the precautionary approach to management, it is recommended that mitigating options addressing behavioural, regulatory and technological change are rapidly evaluated and implemented to avoid the development of desalination in the region along a business as usual pathway, and multidisciplinary research studies should be conducted to reduce uncertainty in predictions of future impacts.

Le Quesne, W. J. F. 2009. Are flawed MPAs any good or just a new way of making old mistakes? – ICES Journal of Marine Science, 66: 132–136. The case for Marine Protected Areas (MPAs) is often supported by the observation that present fisheries management has failed. This overlooks the fact that, often, management plans are not implemented in accordance with advice and that subsequent regulations are frequently violated. Evidence is emerging that MPAs may be equally open to mismanagement, either because MPAs are smaller than recommended or through lack of compliance. Therefore, it is interesting to ask whether MPAs would also fail if they are not properly implemented or enforced. A population model was used to examine this question. The model demonstrates that biomass and yield are reduced, and can collapse under “bad” MPA management. When illegal, unreported, or unregulated fishing occurred within the MPA, yield and biomass declined almost linearly with increasing poaching pressure. Yield was more robust than biomass to the effects of making MPAs smaller than the optimum size for limited reductions in MPA size. Varying the degree of mobility had little impact on the response of yield and biomass. This analysis demonstrates the vulnerability of MPAs to design and governance failings, and the importance of considering enforcement during MPA design.