SEAwise report on historic and future spatial distribution of fished stocks

This SEAwise report assesses the distribution of fish species across European seas. To this end, an ICES workshop, WKFISHDISH2, was co-organised to reach out to the broader scientific community and acquire as much knowledge as possible on scientific surveys and species distribution models. A large amount of historical scientific survey data, stored in the DATRAS and MEDITS databases, served as basis for the development of guidelines on how to appropriately pre-process such data, analyse them with state-of-the-art species distribution models (SDMs), and define metrics on how to compare species distributions. Distribution maps were generated separately for the Mediterranean Sea and the Northeast Atlantic spanning the Baltic Sea, North Sea, Celtic Seas, Bay of Biscay and Iberian Coast.  In general, there was good agreement between the distributions generated by different models that were applied to four different reference species with different characteristics in terms of spatial distribution. Differences between models were mainly related to the configuration of spatiotemporal processes, and the extrapolation, mainly in areas with few observations, or where correlates extend to values outside the observed range.  Trends in species distribution were species specific. Some species have shifted in a northward direction, while the distribution of other species was static, or characterized by a southward trend. It is difficult to have a mechanistic understanding, e.g. migration due to climate change, local outbursts, and/or local depletion of fish stocks, of these changes based on survey data that does not allow tracking of individual fish. Potential climate related shifts were instead investigated by linking the survey data with oceanographic variables generated through coupled hydrodynamic-biochemical models. This allowed us to explore how species distributions may change under different scenarios of climate change.  More information about the SEAwise project can be found at www.seawiseproject.org</p

SEAwise Report on key drivers and impacts of changes in spatial distribution of fisheries and fished stocks

   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.  To provide a knowledge base for spatially explicit considerations, SEAwise consulted stakeholders throughout Europe and conducted a systematic review of the scientific literature. As a first step, engagement with relevant stakeholder groups in each Case Study identified key issues of relevance to spatial management. The input from this stakeholder consultation was supplemented by a systematic literature review with careful consideration of the objectives, search terms, inclusion/exclusion criteria, the method for data/knowledge extraction and ultimately how these data and knowledge will be used. The purpose of the task was to quantify the key drivers and pressures behind the changes occurring in commercial fish stocks and fisheries distribution that have a spatially explicit content, map the relevant existing scientific knowledge and provide input to the subsequent SEAwise tasks.  The words identified by the stakeholders consulted focused on factors causing changes to the distribution of commercial fish/shellfish (climate change, MPAs, species interactions, pollution, habitats and invasive species) and fisheries (windfarms, MPAs, Marine spatial planning) as well as the other human impacts. The systematic review extracted data from 331 papers. The most frequently studied topic was the distribution of fish and the region with most papers was the North Sea with about the twice the amount of papers in each of the other regions. The most frequently studied species in the literature were cod, hake and plaice and by far the most frequently studied fisheries was demersal trawl fisheries.  Among the issues identified by stakeholders as key, the effects of environmental conditions on the distribution of fish were particularly well represented in the reviewed material. In contrast, factors determining the distribution of fisheries were almost exclusively studied in trawl fishing in the North Sea and papers on the effect of area restrictions on fish and fisheries were largely restricted to Western waters and the North Sea. While knowledge on the effects of habitats on species did exist, this was restricted to the Baltic Sea and North Sea and papers addressing this outside these areas were close to non-existent. This points to important areas for future work in SEAwise. This report describes part of the results of the SEAwise project. More information about the project can be found at https://seawiseproject.org/ </p

SEAwise Report on the key drivers of stock productivity and future environmental scenarios

An ecosystem approach to fisheries management requires the consideration of commercial species as components of an ecosystem and the acknowledgement of the links between their productivity and the surrounding environment. To provide a knowledge base for such links, SEAwise consulted stakeholders throughout Europe and conducted a systematic review of the scientific literature. The systematic review resulted in 2050 articles from the literature search that were screened for their tile and abstract. 516 of them were retained for data extraction. The majority of studies were conducted in the Baltic Sea and the North Sea, followed by the Western Waters, and with only a few dozen papers in the Mediterranean Sea. Cod and herring were the most studied species, temperature and more generally climate and hydrodynamics indicators were the main drivers investigated, and reproduction was the main productivity-related process. The output of the systematic review is a database of scientific articles organised by regions, species, environmental drivers and productivity-associated processes and where outcomes, but also spatial and time scales, analytical methods etc. are described in a standardised fashion. This database will be analysed in the coming months and used in the downstream tasks of WP3. The most frequently driver identified by stakeholders across regions was climate change followed by species interactions, cod, pollution, commercial fish/shellfish and plankton. Climate change effects on stocks through temperature and salinity are relatively well covered in the literature as are effects of plankton and species interaction. Studies of the effects of pollution do not occur frequently and as a consequence require a dedicated effort is made in SEAwise to remedy this. Species reported frequently by the stakeholders included cod, seabass, sardine, sole, crabs, flatfish, Norway lobster, octopus, shrimps, herring, sprat, anchovy, hake, new species (species increasing in abundance as a result of climate change as well as invasive species of commercial interest) and sandeel. Among these, more than 10 papers were retrieved for cod, sardine, sole, herring, sprat, selected flatfish, anchovy, hake and sandeel. For the remaining species, a dedicated effort must be made in SEAwise if they are to be included in stock models.  This report describes results of the SEAwise project. More information about the project can be found at https://seawiseproject.org/</p