Tag Archives: fisheries

Participatory modeling of fisheries for supporting maritime spatial planning

No HorizonModelling the interactions between fishery and stock dynamics as well as the economic fishery importance on a highly spatial disaggregated scale like in DISPLACE, is useful in context of broader spatial planning, marine management, and stakeholder involvement.

It is important to develop supporting tools for impact evaluations that can inform all parties (scientists, stakeholders, and managers) on the overall fishing sector dynamics on a highly disaggregated scale to develop a collective understanding and common discussion platform based on quantitative predictions of impacts and beneficial/detrimental effects of any new spatial marine planning project . As such, the DISPLACE model can be used to obtain further information on fishermen behaviour with direct input from stakeholders (e.g., here).

windmillsSuch an approach should foster management choices to be based on a more objective and transparent basis and on actual feedback from the stakeholders when they react to spatial planning. More participatory management requires quantitative support and a common platform for input that will likely promote good fishing practices and achieve better compliance with the regulations and where stakeholders can feel more engaged in the ecosystem-based fisheries management decision process (also advocated here).

The goal is to also inform managers with quantitative supports about the potential gain of spatial regulations against the cost for displacement when fishermen loose access to valuable fishing grounds and/or have to travel more to go fishing from their home harbour to make a living out of the catches.

High-resolution mapping of fishing activities: toward well-informed marine spatial planning

Multi-sectoral and multi-disciplinary marine spatial planning methods are prevailing in the EU Marine Strategy Framework Directive. Such integrated marine management needs to consider the commercial fishery and all other sector uses of the sea, such as transport, energy exploitation and recreational use.

Consequently, each of these pressures on the marine ecosystem needs to be mapped.

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Mapping of the 2005 Danish landing value (left: Cod; right: Nephrops, click on images to see animations per year-quarter) over the North Sea and the Baltic Sea for VMS-equipped fishing vessels. (Source: here)

Simultaneously, the EU Common Fisheries Policy recently recognized the importance of accounting for heterogeneity in fishing practices from different fleets for managing
commercial fisheries. It was acknowledged that a shift should take place from managing individual fish stocks towards managing fleets, mixed fisheries, and economic issues.

Fine-grained VMS data enable obvious improvements to describe used areas and spatial fishing pressure with higher resolution than the ICES rectangles. Hence, the linkage of VMS with logbooks constitutes very valuable information for mapping the spatio-temporal heterogeneity of landings and economically important fishing grounds to act as the basis for management decisions and designation of priorities areas.

COLOURBOX527799_fishing_net_small_sizeThese maps can be used directly for conditioning the DISPLACE model and inform area-based management performing strategy evaluation and scenario modelling of different management options associated with, for example, the establishment of spatial regulated areas and displacement of fishing effort in relation to ecosystem conditions (sensitive habitats), variability in fish stock occurrence and other uses of the sea.

Impact assessment of windmill parks on fisheries

DONG Wind Farm 1An on-going work is to apply and downscale 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 windmill parks in the Baltic area are affecting the fishing opportunities per activity and fishing communities in the vicinity of the planned windmill sites.

Hence, preliminary data mining shows that the planned offshore windmill parks in the area do not really interfere with important fishing grounds for the Danish fisheries. A notable exception is the large ‘Kriegers Flak’ site (where turbines will be shared between Denmark, Germany and ultimately, Sweden). A windmill farm here will impact important existing fishing grounds.map_spatial_dependency_and_planned_windmillfarms_sitesTwo indices of spatial use by the Danish vessels (>12m) visiting the Kattegat and the Baltic Sea in 2012, (a) revenue of the vessel visiting the cells over the total revenue, and (b) revenue realized on the cells by the visiting vessels over the total revenue of the same vessels. The gradient colour shows low (blue) up to high (red) index values. The planned (from 2013) windmill parks given in purple polygons (Source: compiled by DTU-Aqua)

Indices of activity (margin figure) reveal that this area is not really an important area in terms of total revenue at the scale of the entire Danish fisheries because not visited by “big players”. By contrast the area is important for a large portion of vessels (likely conducting small scale fisheries) which realise a significant portion of their total 2012 revenue in the designated area. Accordingly, it will impact many fishing businesses and the local societies. If this impact leads to major disruption of the fishing activities and/or major consequences on the population dynamics should be further investigated by modelling applying the DISPLACE model.

The evaluation intends to cover the implications in terms of individual profitability, and also in terms of the sustainability of the exploitation of the main commercial stocks in the area (i.e. sprat, herring, cod and flatfish) and possibly the likely effect on the benthic communities from redirected bottom-disturbing activities. Integration of the Swedish and German vessels (also operating in the area) on top of the Danish ones is also planned to expand the impact evaluation.