DISPLACE: a dynamic, individual-based model for spatial fishing planning and effort displacement - integrating underlying fish population models, check out the paper at Canadian Journal of Fisheries and Aquatic Sciences and at ICES Journal of Marine Science, and have a look at the DISPLACE blog.
- A bi-directional model. The DISPLACE model combines the fishing activity and resource dynamics with very high resolution in time, space and fishing units, which is rarely done although it is in literature recognized as necessary. That is, to take into account fish population responses to fishing and induced fishermen behavior, impacting on local scale and on single fishing operation level, in the assessment of various management actions.
- An individual-based model. There is a need to better encompass the connection between the micro-scale fishermen decisions and their economic causes and consequences at the macro-scale level (e.g. via the stocks and fish market dynamics) when evaluating the economic viability of the fishing sector and the sustainability of the marine ecosystems (stocks). In the DISPLACE model, vessels are simulated individually to visit their own specific grounds and ports at their own frequency which regenerates the individual fishing variability otherwise usually encapsulated into a regional aggregation.
- A supporting tool for impact assessement. We want to develop a collective understanding and a common discussion platform based on quantitative predictions of impacts and beneficial/detrimental effects on fishing activities of any new spatial marine planning project.
Provides input to:
- impact on economic returns from traditional fisheries.
- effect on MSFD indicators (e.g. spatial fishing pressure/footprint) and their economic value.
- Impact assessment of Maritime Spatial Planning MSP on the fishery economy.
A decision support tool
Implementation of simulation models and tools for making integrated evaluation of impacts of different management options in fisheries under different environmental and climatic conditions (regimes), e.g. spatial planning:
- Biological impact on several stocks according to sustainable exploitation, MSY (multi-stock- level)
- Economic impact on several fisheries according to economic sustainability (profitability) and fleet reactions such as capacity changes and effort re-allocation (multi-fleet-level)
- Energy efficiency (and CO2 emission) in relation to spatial allocation of fisheries effort by fleet
- Ecosystem impact spatio-temporal fishing pressure on Benthic habitat and communities
DISPLACE operates with high resolution in time and space (a spatio-temporal explicit model). It allows contributing to marine spatial planning for evaluating the effects on stocks and fisheries (impact assessment on stocks and fisheries of marine management) and ultimately incorporating other utilization of the sea such as energy production, transport, recreational use, etc., e.g. offshore windmill farms, large marine constructions, NATURA 2000 areas, transport routes of commercial shipping, pipelines, cables, etc. Evaluation in terms of economy including evaluation of spatial restrictions in fishery. The model output will provide stock biomasses and fishing mortalities for different exploitation patterns in space and time by different fleet components, and covers the full fishery system with technical interactions. This includes fishery pressures on the meso-pelagic community and fishery economic efficiency (cost, revenue, profit) as well as energy efficiency on vessel/fishery/ fleet basis. The model is spatial explicit and can be adapted to whatever spatial and temporal scales relevant in the Atlantic.
- Fisheries biological output for use in sustainability analyses: Spatially (and temporal) resolved time series of exploited species biomass and fishing mortality, which can be evaluated according to sustainability targets (e.g. MSY) given landings/discards by multiple fisheries divided into fleets/metiers.
- Fisheries economic output for economic analyses in socio-economic and cross sector economic perspective: Revenue by species and commercial sorting of landings by vessel/fleet/ metier), fleet capacity dynamics, cost dynamics (fixed and variable costs – among other in relation to fuel), price dynamics (price-resource functions), and profit parameters for the different fleets and fisheries (metiers) as well as totally for the fishery on national (and cross national) basis.
- Fishery energy efficiency output: The model provides output on fuel and energy efficiency given different targeting and fishery effort allocation for vessels, fleets and fisheries (metiers).
- Fishery spatial anthropogenic pressure on seabed output: The model provides estimates of spatial fishing pressure (footprint in km2 of swept area, linked to the MSFD indicator) from the spatial application of various types of fishing gears and gear components from different gear widths, vessel engine powers, and penetration into the seabed. Fine time series of the spatial fishing pressure can be generated and aggregated (hourly to annual).
Combining the fishing activity and resource dynamics is rarely done although recognized necessary. The reasons for a low number of investigations so far on this include lack of available data, high complexity, and uncertainty in relation to numerous factors.
Recent years developments in establishing more detailed, spatial and temporal explicit, and disaggregated fisheries data through e.g. EU STECF (Scientific and Technical Evaluation Committee for Fisheries) fisheries catch and effort databases, coupled national VMS, logbook and sales slips data, as well as disaggregated stock dynamics and distribution data by e.g. merging ICES (International Council for Exploration of the Sea) stock assessment data with standardized ICES research survey databases (ICES; fishframe; fishbase) provide adequate data to parameterize and inform more complex individual vessel based multi-stock-multi-fisheries management evaluation models. By use of the newly available disaggregated documentation (from international and national standardized and quality controlled extensive databases) the fisheries and underlying resource dynamics can be better documented in the models. The assumptions in relation to fishing behavior on e.g. effort allocation and re-allocation as well as on local depletion of underlying resources can be reduced by using direct observations of individual behavior and establish documented model decision trees. Accordingly, model transparency can be enhanced.
High resolution catch (weight and value) and effort from trip based log-book information and Satellite VMS-information (i.e. logbook coupled to VMS data). High resolution resource availability data from e.g. disaggregated research survey or combined fishery information on disaggregated resource availability. ICES rectangle-based landing and effort data from the EU STECF data for smaller vessels and missing countries. Stock assessment and fishbase data. Landings data. Various maritime spatial uses. Benthic habitat maps with vulnerability and growth/recovery per Benthos functional groups.
- Representing the fishing arena
- Representing fish populations and fishing vessels
- Fish populations
- From scientific research surveys
- Bottom Trawl research surveys
- From statistical population modelling
- Fishing vessels
- Harbours and fish prices
- Catch equation and harvest-based processes
- Management Strategy Evaluation
- User-defined Simulation settings
- Different uses of the sea and maritime spatial planning
- Benthic habitats and communities
- Scenarios and combinations.
- Large-scale application (Baltic + North Sea). The DISPLACE model documents and implements the dynamics of 16 commercially important fish stocks for the North Sea and the Baltic Sea (here). Because these stocks have a spatial and seasonal structure the abundance of these stocks is modelled explicitly to obtain higher resolution spatially as well as disaggregated quarter-based abundance surfaces. This is based on a) the availability of detailed stock structure information from the yearly stock assessments (e.g., stock numbers by age) performed by ICES (http://www.ices.dk) for each of those stocks in their full stock distribution area, and then b) spatially distributed by length group according to relative catch rates from the ICES IBTS and BITS research vessel surveys (http://www.ices.dk). In addition, 22 stocks that are not routinely assessed and for which the total stock numbers are mostly unknown (or with too high uncertainty) are accounted for in the catch process (total yield and revenue from those species), while the dynamics for those stocks are not explicitly modelled.
- Western Baltic Sea. An on-going work published here is to apply the DISPLACE model to the commercially important and busy Western Baltic marine area where several utilisations of the sea currently coexist. In line with this it is evaluated to which extent the international plans for offshore wind mill farm sites in the Baltic area is affecting the fishing opportunities per activity and fishing community in the vicinity of the planned windmill sites.
The core model written in C++ code is hosted on a GitHub repository. Example data sets and R routines are also hosted on GitHub on separated repositories. The DISPLACE software will soon be offered for download on both Windows and Linux platforms, most likely within Feb 2015.
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