A spatial model of fisheries to help sustainable fishing and maritime spatial planning
Author: Francois Bastardie
Francois Bastardie is a DTU-Aqua Senior Scientist and method developer in the Section of Ecosystem-based Marine Management with a Ph.D. in Biological Science. He has been involved in several national and EU Funded projects developing expertise in spatial fisheries and fisheries databases. He has a strong background in modeling fishing and the bio-economic dynamics including developing agent-based models for combining marine ecosystems and natural resource extraction models, fisheries economics in a mixed fisheries perspective. He has an experience of 10 years leading to more than 35 peer-reviewed publications by conducting scientific-based fisheries management evaluation with scenario-testing evaluation and simulations, including fleet dynamics and consequences on the economy of fisheries, population dynamics and fish stock assessment. He was in charge of the evaluation of some of the EU long-term fisheries management plans with consequent participation to ICES and STECF working groups, including giving advise from regional to international policy makers.
Acting with imperfect information, fisheries policymakers and managers must try to balance tradeoffs of fisheries short-term productivity against long-term environmental, economic and social sustainability.
Alternatively, both environmental and fisheries policy strategies could engage a virtuous circle by bridging the historical divide between fisheries and nature agencies.
Hence, a long-term win-win situation could better emerge, and by propagating the change induced by the reduction of fishing impacts to other supportive marine ecosystem components (habitats, non-commercial marine species), the fisheries management could contribute to secure future fishing opportunities for the fishing fleets along with fulfilling the market demand for seafood and ensuring coherence in meeting national environmental targets.
Building on previous scientific works, we contributed to making this point more apparent in:
Bastardie, F., & Brown, E. J. (2021). Reverse the declining course: A risk assessment for marine and fisheries policy strategies in Europe from current knowledge synthesis. Marine Policy, 126, . https://doi.org/10.1016/j.marpol.2021.104409
You are welcome to ask for a free copy of the published article to fba at aqua.dtu.dk or find a preprint version here:
• Restricting fishing areas does not equate to reducing ecosystem impacts on benthic habitats.
• Displacing fishing efforts can offset the gains in partial habitat protection.
• The benthic status in Kattegat improves more than the benthic status in central Baltic when using spatial management measures.
• Largest improvement is achieved by protecting long-lived communities from high-impact fisheries.
• Healthy fish stocks reduce the risk to both the seafloor integrity and fishery economics.
Sophisticated computer simulations can support effective science-based evaluations to facilitate better governance of the marine space with evidence-based policies. We developed a range of spatial fisheries models, integrating biological with fishers´decision-making dynamics and management for assessing the management of multiple activities. We present the outcomes of case-specific evaluations with different ecological and socio-economic characteristics i.e. Adriatic, Ionian, Black, Baltic and Celtic Seas, and priorities like fisheries, aquaculture, offshore wind energy or conservation areas. For each case, we applied the DISPLACE agent-based modeling platform for simulating bioeconomic dynamics and clarifying options for sustainable and viable fisheries in presence of other marine sectors. The work is ongoing and we foresee clear outcomes delivered by mid-2019.
The ban on discarding unwanted fish overboard when fishing, which was decided during the last 2013 EU Common Fisheries Policy reform, requires that everything retained in a commercial fishing gear is recorded and counted against fish quotas when some exist like in Northern European waters. It is, however, difficult to reduce catches of a single fish species when a variety of fish is generally caught together. This creates a risk for early closures of fisheries when the quota of one fish (the “choke species”) is exhausted before the others. To cope with this and avoid an unnecessary low rate of quota utilization, fishermen can try to lease extra quotas, or modify their catches, either by switching to more selective fishing gear types or through changes in when, where and how to fish, by trying to avoid areas where there is a fair amount of possible choke species, and displace the fishery as soon as a large catch of choke species is encountered. This ability to displace will depend on the skills and choices of the skipper but also on how the fish stocks distribute in space and time (patchily vs. evenly distributed). We are developing here a platform to test such interlinked effects in a clear and detailed manner by accounting for varying skipper’s decision-making, such as for example the one described in the adjacent decision tree.
By analyzing fishers´ decision making consequences and predicting likely responses of fisheries to spatial management options, the DISPLACE modelling approach is assessing whether actual fishing opportunities and technical management measures (e.g. regulation of gears, spatial restriction for fishing, etc.) perform well by ensuring sustainable fishing and food provision to the value chain without affecting important fisheries economics. In this context DISPLACE now provides scenario-based assessment and projections of the amount of income generated by national fishing fleets (or other finer fleet segments level economics and fishing harbor communities) over months, quarters and years as long as national input data are available.
On this issue, important results have been obtained in a row of applications including the Adriatic Sea CS (paper here), the Ionian Sea (in progress), the Black Sea (in progress) and the Baltic Sea CSs, with ongoing data conditioning for the Irish Celtic Sea, some Norwegian Fjords and NE Atlantic Coasts in Portugal.
DISPLACE is a fisheries spatial ecosystem impact assessment tool that can be used to look at the consequences of fisheries and the benefits from managing them (including spatial fisheries closures) for a sustainable use and a viable economy of fisheries exploiting marine resources (fish, shellfish and marine invertebrates). The model simulates the fishing of individual vessels and their capacity to deploy their effort at fishing when constrained by spatial or temporal closures, other management, and including spatial restriction from other concurrent uses of the sea (fish farms, commercial shipping lanes, wind farm parks).
In this context, DISPLACE provides a basis for testing scenarios and projects the amount of income generated by national fishing fleets (or the economics of some finer segmentation such as fishing harbor communities) over months, quarters and years. We track aggregated economics and measure Income, Costs, Economic Indicators, Capital value, Profitability and development trends. DISPLACE is also a platform useful to compare fleet segments regarding their respective fuel efficiency and relative impacts by for example looking at the income issued from the sea for each unit of seabed area swept by the fishing gears.
(Disclaimer! Attached screenshots in this margin are very preliminary outcomes and should not be used to give any kind of advice neither to deduce any kind of productivity levels)
The Adriatic Sea is one of the most crowded marine areas. Several fishing activities operate simultaneously in the area, and the need to minimize conflicts among them is also a social concern. We apply a fish and fisheries model accounting for space and time effects to study the impact that would result from a suite of spatial plans suggested by practitioners in order to reduce the pressure on the four main demersal fish and crustacean stocks (having high commercial interest) in the northern Adriatic. We also look at promoting space sharing between mutually exclusive activities.
Check out the open access paper for more information in Ecosphere
DISPLACE is a spatial impact assessment tool to anticipate the consequences of displacing fisheries on ensuring a better sustainability and economy of fisheries. The model simulates the activity of individual vessels and how they will use their time fishing and where given restrictions in space and time. By applying the model that fit the local fisheries of the Adriatic region, practitioners could further develop tailored applications to their area for both understanding the fine dynamic of the interlinked fish and fisheries here, and, in the meantime, acquire a helicopter view of the outcomes when the small-scale (fishing) operations at sea are aggregated. That kind of framework applied to the Adriatic or other areas should analyze and provide data with thematic reports/scenario on which the practitioners can rely on to project the fish stock population levels and fishery economy relevant to the ecoregion. The model contributes to the coordination and integration of different spatial activities in marine areas with the purpose of reducing potential inefficient management and use of space in accordance with the aims of the EU Marine Spatial Planning Directive (MSPD) and other Directives. In the project, the model is used to estimate the consequences of closing specific areas to fishing.
We are setting the first steps in developing a fish and fisheries DISPLACE application for the northern Adriatic Sea in support of maritime spatial planning and management issues, especially from the perspective of the Italian coastal fisheries. The model provides a test platform for running Monte-Carlo simulations that project scenarios of alternative spatial management scenarios and fishing effort distributions. We evaluate how fisheries revenues and environmental benefits are affected. This first application to the Adriatic Sea should provide technical inputs for the development of a bio-economic model in order to guarantee effective science based inputs allowing policy improvement and better governance at cross-border level for fisheries management and marine spatial planning.
(Attached screenshots in this margin are very preliminary outcomes and should not be used to give any kind of advice)
Fishermen´s micro-decision-making is challenged by fishery management and marine spatial plans and affects the overall performance of fisheries. Because of individual decisions and tactics for fishing (e.g. selection of gears, place and time) influence catching power, the fishermen have an individual footprint on the harvested stocks and benthic communities.
Also, fishermen have different objectives and strategies influencing economic and impact performance of the fishery for several stocks and ecosystem components and in different areas (e.g. here for carbon footprints, or here for impacts on seafloor). By regulating catch quotas, the deployed effort and potential fishing grounds, both fisheries management, and marine spatial plans can result in unintended consequences and incentives affecting the overall economic and energy performance of the fisheries at stake, which may further undermine the ecosystem approach to fisheries.
We intend to support the fishery sector and the policymakers with a benchmark tool for efficiently evaluating alternative scenarios in individual decision making, by designing decision trees to model when, where, how, and for how long they go fishing.