31 research outputs found
Limiting inter-annual variation in total allowable catch strategies. An application to ICES roundfish stocks
This study evaluated through simulation management strategy that stabilise catch levels by setting
bounds on the inter-annual variability in Total Allowable Catches (TACs). An integrated modelling
approach was used, which modelled both the ‘real’ and observed systems and the interactions between
all system components. The modelling framework therefore allowed evaluation of the robustness of
candidate management strategies to both the intrinsic properties of the systems, and the ability to
observe, monitor, assess and control them. Strategies were evaluated in terms of level of risk
(measured as the probability of spawning stock biomass falling below the biomass limit reference
level for the stock) and cumulative yield.
The simulation approach used provides a powerful tool for the examination of the performance of
candidate management strategies. It has shown that better management is not necessarily going to be
achieved by improving the assessement, since even with a perfect assessment (where the simulated
working group knew stock status perfectly) stocks may crash at fishing levels that standard stochastic
projections would suggest were safe. Also explicitly modelling the assessment process can result in
quite different outcomes than those predicted by the simple projection traditionally used by stock
assessment working groups. This is because the simple projection assumes that the status of the stock
in the current year is known without error and that the target fishing mortality can be achieved
without error. However, in practice the assessment is based on last years data and the effect of any
management measure on SSB is only manifest, following the implementation of the quota, at the end
of the following year.
The choice of target and fishing mortality levels and minimum stock levels results from ICES
interpretation of the precautionary approach. This lead to the definition of fishing mortality and
biomass reference points that are intended to prevent over-fishing and to trigger recovery plans when
a stock is overfished respectively. Although, fishing mortality and biomass reference points were
originally intended to be independent, a fishing mortality level implies a corresponding biomass level.
In the case of saithe a fishing mortality of 0.40 (i.e. the FPA level) would drive the stock to Blim,
suggesting that the choice of biomass and target reference points are not consistent for this stock
Limiting inter-annual variation in total allowable catch strategies. An application to ICES roundfish stocks
This study evaluated through simulation management strategy that stabilise catch levels by setting
bounds on the inter-annual variability in Total Allowable Catches (TACs). An integrated modelling
approach was used, which modelled both the ‘real’ and observed systems and the interactions between
all system components. The modelling framework therefore allowed evaluation of the robustness of
candidate management strategies to both the intrinsic properties of the systems, and the ability to
observe, monitor, assess and control them. Strategies were evaluated in terms of level of risk
(measured as the probability of spawning stock biomass falling below the biomass limit reference
level for the stock) and cumulative yield.
The simulation approach used provides a powerful tool for the examination of the performance of
candidate management strategies. It has shown that better management is not necessarily going to be
achieved by improving the assessement, since even with a perfect assessment (where the simulated
working group knew stock status perfectly) stocks may crash at fishing levels that standard stochastic
projections would suggest were safe. Also explicitly modelling the assessment process can result in
quite different outcomes than those predicted by the simple projection traditionally used by stock
assessment working groups. This is because the simple projection assumes that the status of the stock
in the current year is known without error and that the target fishing mortality can be achieved
without error. However, in practice the assessment is based on last years data and the effect of any
management measure on SSB is only manifest, following the implementation of the quota, at the end
of the following year.
The choice of target and fishing mortality levels and minimum stock levels results from ICES
interpretation of the precautionary approach. This lead to the definition of fishing mortality and
biomass reference points that are intended to prevent over-fishing and to trigger recovery plans when
a stock is overfished respectively. Although, fishing mortality and biomass reference points were
originally intended to be independent, a fishing mortality level implies a corresponding biomass level.
In the case of saithe a fishing mortality of 0.40 (i.e. the FPA level) would drive the stock to Blim,
suggesting that the choice of biomass and target reference points are not consistent for this stock
Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2014
Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2014
Swedish University of Agriculture Sciences (SLU Aqua)
Lysekil, Sweden
08-12 September 2014The RCM NS&EA met in Lysekil (Sweden) between 8-12 September 2014. The main purpose of the RCM is coordinate the National Programmes (NP) of the Member States (MS) in the North Sea region for 2015
Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2013
Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2013 final report
European Fisheries Control Agency (EFCA)
Vigo, Spain
09/09/2013-13/09/2013The Regional Coordination Meeting for the North Sea & Eastern Arctic (RCM NS&EA) was held in September 2013 in Vigo (Spain). The main task of the RCM’s is to coordinate the National Programmes (NP), which propose the national data collection to be carried out by the Member States (MS) under the EU Data Collection Framework (DCF). It was envisaged that, from 2104 onwards, data collection by the MS would be carried out under a new framework (DC-MAP). However, the legislation for this framework is not ready yet. Therefore the Commission has decided to extend the present DCF for the time being and the most recent NPs have been adopted for 2014. Since these NP have been adopted without any changes, there is no need for major coordinatio
Report of the Regional Co-ordination Meeting for the North Sea and Eastern Arctic (RCM NS&EA) 2015
The RCM NS&EA met 31st August - 4th September 2015 at den Haag, Netherlands with 27 participants form 11 member states and autonomous regions attending, including representatives of ICES and the Commission. National correspondents from Spain, UK, Denmark, Lithuania, Germany, Sweden and the Netherlands were present. The meeting was co-chaired by Katja Ringdahl (Sweden) and Alastair Pout (Scotland).
The RCM N&SEA considered the recommendations from the 11th Liasion meeting and summaries were presented of the work of expert groups and end users for the 2014-15 period to the plenary session of the meeting. The expert groups included WGCATCH, PGDATA, WKISCON2, WKRDB 2014-01, RDB–SC, STECF and the Zagreb meeting on transversal variables. ICES, as a main end user, provided feedback.
A summary was presented of the progress in the regional coordination project (fishPi). This project involves over 40 participants from 12 members states from NS&EA, NA and Baltic regions, two external statistical experts, and ICES. The project has a wide scope of regional cooperation issues including sampling designs, data formats, code lists, PETS, stomach sampling, small scale and recreational sampling, and data quality software production. It has a budget of €400,000, and a one year time line and with a planned completion date of April 2016. A project with identical aims is running in paralleled in the Mediterranean and Black Sea regions
The majority of the ToRs of the RCM NS&EA were addressed by three subgroups: one concerned with data analysis, one with the landing obligation, and one with issues particularly related to role and work of national correspondents
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