International Council for the Exploration of the Sea
Workshop on Tradeoffs Scenarios between the Impact on Seafloor Habitats and Provisions of catch-value (WKTRADE2).pdf (3.9 MB)

Workshop on Tradeoffs Scenarios between the Impact on Seafloor Habitats and Provisions of catch-value (WKTRADE2)

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posted on 2019-10-04, 00:00 authored by ICESICES

The second Workshop on Tradeoffs Scenarios between the Impact on Seafloor Habitats and Provisions of catch/value (WKTRADE2) was established to provide input on trade-offs aspects to the Working group on Fisheries Benthic Impact and Trade-offs (WGFBIT). As such, the workshop was tasked to: 1) demonstrate the applicability of a set of approaches to better estimate fisheries revenue; 2) establish ways to assess effort reduction scenarios; and 3) explore how to (better) incorporate social factors associated with fisheries.

The workshop suggests that to improve estimates of the “value” of an area to fisheries that the contribution margin (income from landings minus variable costs) should be calculated. To do this two complementary approaches (disaggregation and mechanistic) are presented and can be developed using the current ICES VMS and logbook data, supplemented with economic data layers. A modular workflow to integrate the variables into the assessment is also presented.

Furthermore, the workshop found that redistribution of total revenue among individual fishers and fishers’ communities will need to be considered to accurately predict displacement effects and impact evaluation on fisheries economics. Applying predictive modelling techniques adds to assessing a static picture (current fishing activity) because it considers displacement effects which may elucidate increased pressure on essential fish habitats, sensitive vulnerable habitats, or previously untrawled areas.

To better identify trade-offs between ecological, economic and social factors for use by the ICES working group WGFBIT, the workshop recommends also using integrative approaches (e.g. bio-economic models, stakeholder engagement) that account for direct linkages between fish, fisheries and benthos dynamics to address issues related to MSFD, CFP and spatial management plans in a consistent way. When considering the effects of displacement the contribution margin should be accounted for as the fishing closures are likely to have indirect (positive or negative) effects. For example, protecting part of the fish stocks might lead to better catch rates and therefore fuel savings, etc. The workshop also found static models to be operational and more easily used to identify impacted fishing fleets. While, dynamic modelling approaches allow for the ad-aptation of fishing fleets (e.g. displacement, gear modifications), potentially mitigating the esti-mated impact of spatial and temporal restrictions. Static approaches are easy to use in stake-holder processes, and can facilitate stakeholder engagement. Future development of static and dynamic models will need to account for the influence of other activities (e.g. closures due to wind farm) on fisheries activities. Running scenarios using dynamic models will indicate which areas are most valuable to fisheries after spatial management scenarios are proposed. This elicits the socio-economic valuable fisheries areas.

The workshop’s focus was on the spatial management scenarios so far identified by the working group WGFBIT, but the suggested workflow can also be used to address other scenarios, e.g. technical measures aimed at reducing gear penetration depths, disturbance effects and improving selectivity, habitat credits approaches that define credits related to the sensitivity of habitat and convey credits to the fishing industry to manage either collectively or individually.

The workshop also identified some follow-up work that working group WGFBIT could take on to both to improve the current scenario testing on spatial restrictions, as well as how to deal with fleet adaptation/effort displacement in reaction to the spatial restrictions. This work would ben-efit by stronger links to ICES working groups WGECON and WGSOCIAL to ensure the required fisheries economic expertise.


Published under the auspices of the following ICES Steering Group or Committee


Published under the auspices of the following ICES Expert Group or Strategic Initiative



ICES Scientific Reports





Contributors (Editors)

François Bastardie; Jochen Depestele

Contributors (Authors)

François Bastardie; Jörg Berkenhagen; Isabella Bitetto; Oisin Callery; Paul Coleman; Lorenzo D'Andrea; Jochen Depestele; Hans Frost; David Goldsborough; Katell Hamon; Ayoe Hoff; Helen Holah; Lis Lindal Jørgensen; Sarah B.M. Kraak; Loretta Malvarosa; Roi Martínez; Daniel Norton; Serra Orey; Dale Rodmell; Tommaso Russo; Torsten Schulze; Erik Sulanke; Sebastian Valanko; Daniel van Denderen



Recommended citation

ICES. 2019. Workshop on Tradeoffs Scenarios between the Impact on Seafloor Habitats and Provisions of catch/value (WKTRADE2). ICES Scientific Reports. 1:63. 67 pp.

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