This challenge focused on collecting information on the impact of fisheries in the Arctic. Fisheries impact is interpreted as any disturbance of the seafloor of fishing vessels operating mobile bottom fishing gear. There are several ways to estimate the level of seafloor disturbance depending on the information available.
It is assumed that there is a relationship between the capacity (number of vessels) or effort (usually kWdays) and fishing impact. The degree of impact will depend on the fishing technique that is used. Vessels that use heavier fishing gear (e.g. beam trawls) or larger fishing gear (e.g. multiple combined pair trawls) are expected to need more engine power to haul their nets through the water and over the sea floor, causing a greater impact on the seafloor. This method can be widely applied to include a range of metiers (e.g. a fishing characterised by one equipment type and target species, operating in a given area during a given season) that use mobile (towed) equipment. Gill nets, fykes and creeling cannot be measured in the same way, but will only have a minimal impact on the seabed and are therefore excluded from this analysis.
Objective of the challenge
This challenge focused on compiling information on the actual impact of fisheries in the Arctic. The objective of this challenge was to produce data layers (gridded) showing the extent of fisheries impact on the seafloor for:
- areas where bottom habitat was disturbed by bottom trawling (number of disturbances per month)
- changes in level of disturbance over ten years
- damage to sea floor to both living and nonliving components
To assess the impact fishing has on the sea floor, it is necessary to combine fisheries capacity or effort data with habitat information. This challenge therefore first looked into the data availability of these different variables.
Fishing capacity and fishing effort
Fishing capacity is considered to be a fairly crude proxy of fisheries impact (Piet et al., 2006) as there is no straightforward relationship between fishing capacity and the pressure exerted on the ecosystem. Within this challenge the number of vessels per fishing metier has been used as an indicator for fishing capacity.
Fishing effort is a better proxy for fishing impact and is more often applied in data-limited situations. However, the link between fishing effort and fisheries impact is certainly not directly correlated as the impact of one unit of fishing effort on the ecosystem may differ between metiers and/or the sensitivity of the area exposed to that specific fishing method.
More sophisticated but also more accurate indicators for seafloor disturbance require high resolution data such as data that comes from Vessel Monitoring System (VMS). This data is held by the flag state of the vessel and is subject to data protection regulations. As VMS data from specific vessels come under the data protection act it is not readily available for general use.
The information that was found on fishing impact for the Arctic area is scarce; only fragmented data was found. The Scientific, Technical and Economic Committee for Fisheries (STECF) provides effort information for the Arctic part of the Northeast Atlantic that can be directly downloaded from the STECF website. The Northwest Atlantic Fisheries Organisation (NAFO) provides, amongst others, monthly effort information. However, as the coding is unclear, the data could not be used. Within this challenge we therefore did not succeed in producing a general overview of fishing capacity and fishing effort.
Habitat information was obtained from various sources. Different working groups within the Arctic Council provide some kind of information on important areas within the Arctic area. For example, the biodiversity working group of the Arctic Council (CAFF) presents information on protected and important areas. Within CAFF 11 Ecologically and Biologically Significant Areas (EBSAs) have been identified in the Arctic. EBSAs are “special areas in the ocean that serve important purposes, in one way or another, to support the healthy functioning of oceans and the many services that it provides” (http://www.caff.is). The map can be downloaded here: https://www.caff.is/protected-and-important-areas/.
Furthermore, the working group on Arctic Monitoring and Assessment Programme identified 97 areas of heightened ecological significance, including 40 areas used by fish (mostly spawning areas) within the Arctic Large Marine Ecosystems (LMEs). These areas were identified on the basis of their importance to fish, birds and/or mammals (AMAP/CAFF/SDWG, 2013). Information can be found here: http://geo.abds.is/geonetwork/srv/eng/catalog.search#/home.
There are also different European initiatives, e.g. EUNIS (information can be accessed through EMODnet seabed habitats: http://www.emodnet-seabedhabitats.eu/default.aspx?page=1974&LAYERS=HabitatsNorway2015&zoom=2&Y=39.27348830986956&X=-5.112812498979618) and MAREANO project (http://www.mareano.no/kart/mareano.html), that provide some kind of habitat information for specific Arctic regions of the Northeast Atlantic. Furthermore, the SBC Arctic Challenge on Marine Protected Areas may provide additional information on areas within the Arctic that deserve special conservation and/or are more vulnerable to fishing.
Only fragmented data was found for the different variables that are needed to assess fisheries impact. It was therefore not possible to meet the objective of this challenge, namely to produce data layers (gridded) showing the extent of fisheries impact on the sea floor.
Problems and Gaps
- Only fragmented data was found for fishing impact. Furthermore, the coding of the presented unit of effort data is not always clear making it not possible to use the data.
- Due to privacy issues high-spatial resolution data on fishing effort is not readily available for general use.
- Specific organisations that were addressed to identify accessible data did not reply.
- Assess the impacts of benthic fisheries (both fish and invertebrates) on seafloor habitats and pelagic food webs (e.g. capelin as food source of fish-eating birds). Habitat impacts due to bottom trawling fisheries can be assessed by combining fisheries effort and habitat characteristics.
- Assess the impacts of climate change on benthic fisheries, including Atlantification of the waters and the role of kelp (used to be disturbed by sea ice, but not anymore now that sea ice is disappearing).
- Besides monitoring current and future stocks and impacts, a baseline habitat survey (location and quality) should be developed for areas that are opening up due to sea ice retreat.
- Information on fishing impact is scarce and mostly on low-spatial level resolution; it was not possible to generate an overall overview of fishing impact in the Arctic area.
- Different sources provide information on important areas within the Arctic ocean. These areas are defined in different ways, each providing insight on areas that deserve special conservation.
- AMAP/CAFF/SDWG, 2013. Identification of Arctic marine areas of heightened ecological and cultural significance: Arctic Marine Shipping Assessment (AMSA) IIc. Arctic Monitoring and Assessment Programme (AMAP), Oslo. 114 pp.
- Piet, G.J., F.J. Quirijns, L. Robinson & S.P.R. Greenstreet, 2006. Potential pressure indicators for fishing, and their data requirements. ICES Journal of Marine Science, 64: 110-121.