Synthesis of predicted impacts of changes in habitat and spatial management measures suggested outside SEAwise

The SEAwise project works to deliver a fully operational tool that will allow fishers, managers, and policy makers to easily apply Ecosystem Based Fisheries Management. An ecosystem approach to fisheries management requires the consideration of spatially explicit management measures and other impacts on species and the links between the distribution of fished species, their surrounding environment and productivity. Quantification of the spatial aspects of fisheries and ecology of commercially fished stocks may improve the accuracy of the predicted changes in fish productivity, fisheries yield and costs, benefits and selectivity. This SEAwise report synthesizes results from WP5 on spatial aspects of stocks and fisheries spanning from environmental drivers to habitat change and management options and identify findings that can be included in the SEAwise online EBFM tool. The key spatial aspects explored were:

• Distribution of adult and juvenile commercial species and identification of ‘hotspot’ areas under climate change.
• Fishing footprint and intensity of LSF and SSF fleets in terms of effort exerted, CPUE, discard ratios and revenues.
• Essential habitat availability and suitability and associated productivity changes in fished stocks
• Effect of spatial management on fisheries distribution, yield, profitability, and selectivity and how such spatial plans may affect the remaining ‘fishable’ areas by displacing and concentrating the fishing pressure, and so may alter stock abundances, distributions, size- and species catch composition and fuel expenditure and cost.

The fisheries considered were:

• Demersal fisheries operating in Western Waters (Bay of Biscay), including vessels from Spain and France;
• Demersal fisheries operating in Western Waters (Celtic and Irish Sea), including vessels from Belgium, Germany, Spain, France, Ireland and England;
• Pelagic fisheries operating in Western Waters (Bay of Biscay), including vessels from Basque Country;
• Demersal fisheries operating in North Sea, including vessels from Belgium, Denmark, England, France, Scotland, Germany, Nederland, Scotland and Sweden;
• Demersal fisheries, operating in Central Mediterranean Sea (Adriatic and Western Ionian Sea), including vessels from Italy, Croatia, Slovenia, Albania and Montenegro;
• Demersal fisheries, operating in Eastern Mediterranean Sea (Eastern Ionian Sea), including vessels from Greece;
• Trawl fisheries operating in the Western Baltic Sea, including vessels from Denmark, Sweden, and Germany.

Trends in species distribution were species specific. Some species shifted in a northward direction, while the distribution of other species was static, or characterized by a southward trend. Linking survey data with oceanographic variables generated through coupled hydrodynamic-biochemical models allowed us to explore how species distributions may change under different climate change scenarios. For the species considered in this analysis, temperature seems to be the main effect on density, but does not necessarily have strong effects on spatial distributions.

Limited effects of climate change on fisheries distribution were predicted, probably because we focused on demersal species that will likely exhibit smaller distributional changes under climate change. However, future changes in fisheries management targets, access regulations, international agreements, fish and fuel prices, technological developments, and marine spatial planning will likely play an equally or more important role in shaping future fisheries as climate change over the next few decades. Fisheries scenarios for summarizing different pathways, including future developments in fuel and fish prices have recently developed and should be further explored.

Our findings suggest that fish habitat should be considered in more detail in future management of fishing resources. Both the high level of surface loss and the degraded quality of coastal ecosystems impact the productivity and renewal of marine species exploited by fisheries. If substantial recovery of essential fish habitats could be achieved, this restoration will likely lead to greater productivity which may be as beneficial as regulating fishing pressure.

Various spatial management options were investigated to provide early insights into how spatial plans that exclude certain fishing activities may affect fisheries distribution, yield, profitability, and selectivity. The performance of spatial management measures was assessed through scenario-based testing. Although spatial management may increase operating costs by displacing the effort, this may eventually be recovered in the long term if the stock is recovering from previous overfishing. Certain conservation measures (such as Marine Protected Areas) that limit specific fishing techniques and areas were investigated in depth to evaluate if and how they can mitigate the negative effects of fishing. On average, the prohibition of certain fishing techniques in all currently designated MPAs has minor impacts on the fisheries economy of most fleet-segments examined and fish populations. This is primarily because these areas are preserved due to their significance as hotspots of EU marine biodiversity, rather than selected for a high abundance or productivity of fish species with a commercial value. In upcoming tasks SEAwise will further investigate the effect of such conservation areas (MPAs, hotspots of protected/vulnerable species, nursery/spawning grounds and Fisheries Restricted Areas - FRA) on bycatch and benthic impacts (WP4) and fisheries distribution, yield, profitability, selectivity and ecosystem effects (WP5).

Finally, a dedicated WP5 Synthesis workshop provided feedback for the development of SEAwise EBFM tool and toolbox, which will contain the results of the spatially explicit approaches investigated in SEAwise.

Read more about the SEAwise project at www.seawiseproject.org