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Intersessional Subgroups

What is the role of the ISSGs?

Regional cooperation is meant to improve the efficiency of data collection through sharing of expertise, data, best practices, knowledge and collaborative tasks. The RCGs bring together several Member States to coordinate planning and implementation of data collection .Their workplan across the year, from one round of the annual technical meetings to the next, is supported with the setup of the Intersessional Subgroups.

In these subgroups the experts concentrate on specific Thematic Focus Areas, and sometimes they are pan-regional. During the relevant RCG’s technical meetings, the different ISSGs present progress and hurdles encountered across the period and propose the update of their Terms of Reference with the tasks and targets for the new intersessional period for approval. The work performed by ISSG is essential for RCG technical meeting preparation and meeting discussions

Some of the RCGs refer to the ISSGs as Working Groups, their general purpose is the same, although there may be slight differences on their procedures to adapt to the dynamics of the RCGs to which they are more directly related.

Access to ICES Sharepoint for RCG Intersessional Subgroups (ISSGs)

Intersessional subgroups (ISSGs)

RCG Overviews

The intersessional subgroup on RDB catch, effort and sampling overviews was established to streamline and facilitate the work on the fisheries and sampling data of the MS and prepare data overviews in advance of the RCG meetings. Before the subgroup was set up, the different RCG conducted data analysis and overviews separately with minimal exchange, resulting in redundancies and efficiency loss. Furthermore, a substantial part of the work was being carried out during the RCG meetings themselves and so not readily available to inform RCG preparation and meeting discussions.

The tasks and output from the subgroup fall into 2 main types of work

i) To develop tools for internal RCG work and

ii) Preparatory work for decision making, including input for regional work plans.

At present, three different documents are being developed utilizing RDB data:

  1. Catch and Effort Annual Overview
  2. Catch and Effort Multiannual Overview
  3. Sampling Overvies

Chairs: Ana Claudia Fernandez (PRT), Lucía Zarauz (ESP)

Involved RCGs: RCG NANSEA, RCG Baltic, RCG LDF


The intersessional subgroup on Electronic Monitoring Technologies was established in 2021 to ensure that initiatives made on developing new electronic technologies and the use of these technologies to improve fisheries data collection in EU Member States as well as initiatives made in third countries are disseminated. 

Furthermore, to convey that cooperation is made possible and that all ideas are taking into account when developing the best possible new electronic technologies and its implementation.   

The tasks and output from the subgroup are as a first step: 

Initiate the development of an intinery of the use of the following data collection technologies:  

  • Electronic monitoring (EM)  
  • Machine learning development, e.g., for automatic species identification and catch weight estimations in real-time 
  • Electronic measuring boards 
  • eDNA for species identification 
  • etc.

Second step would be initiation of cooperation when ever possible for cost efficiency in fisheries data collection by the use of electronic technologies. 

Chairs: Gildas Glemarec (DBK), Pieter-Jan De Temmernan (BEL)

RCGs involved: RCG NANSEA, RCG Baltic, RCG LDF 


Umbrella group (currently ON HOLD)

The aim of the ISSG Optimized and Operational Regional Sampling Plans, also referred to as the “Umbrella Group”, is to develop guidance for the development of optimized and operational regional sampling plans (RSPs) and collate ‘theoretical gaps’ and new developments in optimization tools relevant for the development of RSPs. The “Umbrella Group” supports the development of RPSs by different case studies, by interacting with the case studies and providing guidance in terms of work flow, highlighting needs identified by them or evident from their work, promoting links between them and drawing knowledge from lessons learned from their work. Moreover, in terms of methodologies and tools used by the case studies for the development of RSPs keeps an updated overview of existing optimization tools and of their application in the RSPs case studies. 

Chairs: Kirsten Birch Håkansson (DNK), Harriet van Overzee (NLD), Rita Vasconcelos (PRT) 

RCGs involved: RCG NANSEA,   RCG Baltic

CS pelagic freezer trawler NEA

The EU freezer trawler fleet targeting small pelagic species (mackerel, herring, horse mackerel, blue whiting, sprat and argentine) in the North Atlantic and North Sea was identified by the RCG as a potential candidate for the development of a regionally coordinated sampling plan. The fleet comprising mainly Dutch, German, UK and French flagged vessels is sampled currently by the Netherlands and Germany. The primary aim of this subgroup is to propose a statistically robust regional sampling plan for the European pelagic freezer trawler fleet to be considered for inclusion in a regional workplan. 

Chairs: Harriet van Overzee (NLD), Jens Ulleweit (DEU)

RCG involved RCG NANSEA 

CS trawler Iberian Waters

Trawl fisheries in Iberian waters (27.8.c and 27.9.a) are operated mainly by Portuguese and Spanish vessels which land mostly in national ports. These fisheries are multi-specific and important in terms of landed weight and value.

In recent years there has been an interest in developing and implementing a regional sampling plan for these fisheries aiming at optimizing the sampling effort and quality of biological data on these fisheries.

Work towards this end has been developed in previous projects FishPi (2016-2018) and FishPi2 (2018-2019), specifically building theoretical scenarios of regional sampling plan, respectively for single species and multi-species. This work has been further developed in the RCG NANSEA, namely in one of its ISSGs (Inter Sessional Sub Group), and in Project Fishn’Co.

Such work has consisted in using existing data on fisheries landing and effort to theoretically design possible alternative scenarios of distribution of on-shore sampling effort among Portuguese and Spanish fishing ports of 8c and 9a. The best scenarios were selected based on bias and precision of the estimates produced by the scenarios (in simulations); and also based on feasibility and suitability of the scenarios (i.e. if effort in each port could be implemented as proposed in the scenarios, if relevant ports with landings of relevant metiers/fleets/species are included, and if foreign landings could be sampled).

Work is being developed in the short-medium term towards the definition of a pilot study to be implemented in practice, followed by an evaluation of the estimates obained. 

Chairs: Rita Vasconcelos (PRT)

RCG involved: NANSEA  


The intersessional subgroup case studies for Protected, Endangered and Threatened Species (PETS) monitoring was established with the aim of improving coordination in the collection of PETS data at regional level.

The main tasks that have been carried out during the last years have been to identify the high-risk fisheries and their sampling coverage at regional level, to identify the most appropriate sampling methodologies for each fishery, to improve and standardize sampling protocols, etc.

In addition, potential case studies for regionally coordinated sampling programmes have also been identified. Much of this work is being done in collaboration with the main ICES working groups involved in these issues (e.g., WGBYC, WGCATCH). 

Chair Estanis Mugerza (ESP)

RCGs involved RCG NANSEA, RCG Baltic 


The intersessional subgroup evaluation on the data collected for the Small-Scale Fisheries (SSF), was established with the aim of improving coordination in the collection of SSF data, in order to improve the knowledge of these fisheries. Based on the needs of the main end-users, the data to be collected are identified and the best way to do this in a regionally coordinated manner is analysed.

This work is carried out in collaboration with the main ICES working groups focused on issues related to commercial fisheries sampling methodologies (e.g., WGCATCH). 

ChairEstanis Mugerza (ESP)

RCGs involvedRCG NANSEA, RCG Baltic 



WGRDBESGOV is a governance group which oversees the current Regional Database (RDB) and the new Regional Database & Estimation System (RDBES) that is under development.  

​​​​​​​​​WGRDBESGOV consists of members from the EU Regional Coordination Groups (RCGs) that upload data to the RDB/RDBES​, and from ICES member countries. The group explores data governance questions including data policy, gives guidance on technical developments, and monitors the use of the RDB/RDBES.  

The RDB/RDBES stores detailed commercial fisheries sampling data and aggregated effort and landings data. The aims of the RDBES are:  

  1. to ensure that data can be made available for the coordination of regional fisheries data sampling plans, including for the RCGs,  
  2. to provide a regional estimation system such that statistical estimates of quantities of interest can be produced from sample data,  
  3. to serve and facilitate the production of fisheries management advice and status reports, and  
  4. to increase the awareness of fisheries data collected by the users of the RDBES and the overall usage of these data 

Chairs: Els Torreele (BEL), Lucía Zarauz (ESP)

RCGs involved: RCG NANSEA, RCG Baltic, RCG LDF, RCG LP


The intersessional subgroup for diadromous fishes is a specialised, pan regional subgroup focusing on coordination of data collection and advice for regional workplans on diadromous fishes (primarily eel, salmon, sea trout) in line with DCF regulation. Tasks may include listing end-user needs (variables required, frequency, intensity), coordination of possible needs for regional agreements and suggesting time frames for implementations. Data needs of end-users may include both, commercial and recreational fisheries in marine and inland waters of which the latter always needs to be discussed in close coordination with ISSG recreational fisheries. 

Currently the focus of the ISSG Diadromous still is to improve assessment-driven data collection under DCF and to strengthen the interaction between end-users and the ISSG Diadromous / data collection itself. This is intended to be done by encouraging end-users for direct input on data needs for improvement of assessment and comparability in used methodologies as well as by considering regional differences and difficulties in data collection. The goal is to let end-users and ICES EGs further specify the data needs meant for stock assessment and policy advice and thus directly influence data collection. Inputs from end-users is of importance, since ISSG Diadromous has a wide scope including multiple species with different life cycles and stocks, of which the ISSG cannot determine and specify data needs on its own.  

Main tasks of the group are 

  • Strengthening of communication with end-users (to get and provide direct input on issued connected to data availability for assessment) 
  • Promotion of data workshops (to collect best data for assessment) 
  • Promotion of transition from national to regional work plans in the suitable parts of data collection for diadromous species under DCF 

Chairs: Marko Freese (DEU), Simon Weltersbach (DEU), Josefin Sundin (SWE)

RCGs involved: RCG NANSEA, RCG Baltic, RCG MED&BS 



This ISSG mainly deals with the cost-sharing of research surveys-at-sea under the DCF EU-MAP. In addition, the group monitors implications such as COVID-19 on surveys from a DCF perspective and react when appropriate and requested. We link to the regionalisation process within and act as focal point for RCG contact. We review proposed substantial changes to the design, set-up or other aspects of surveys having an impact on MS’s Work Plans, effort and/or budget allocation, or obligations. We contribute to Regional Work Plans with regard to surveys and finally also discuss new challenges in fishery-independent data collection due to usage and protection of marine areas. 

ChairsSieto Verver (NLD), Christoph Stransky (DEU) 

RCGs involvedRCG NANSEA, RCG Baltic 

End user and RCG  

The aim of this ISSG is to review and the streamline
dialogue between data providers (RCGs) and end users (ICES, Commission) in
order to identify effective processes to meet end-user needs and allow the RCG
to prioritize its activity relating to future data collections, storage and
transmission functions. Annual information meetings between ICES, Commission
and RCG chairs are held to ensure good cooperation and to be able to follow the
progress over time. 

The tasks of this ISSG include: 

  • Continue with the designed questioannire on the impact of
    various factors on data collection from commercial fisheries and research
  • Communication channel between ICES and RCG chairs 
  • Communnication channel between Commission and RCG chairs 
  • Communication channel between end-user and RCG chairs

Chairs NANSEA and Baltic RCG chairs

RCGs involvedRCG NANSEA, RCG Baltic

Stomach sampling 

Fundamental changes in the importance of natural versus fishing induced mortality have been observed in the North Atlantic while moving towards maximum sustainable yield (MSY) management targets. The reduction of fishing mortality in combination with successive recovery of fish stocks, especially of some larger predatory species, led to an increasing natural mortality as opposed to fishing mortality. Consequently, estimates of natural mortality have become more important for stock assessments and forecasts.  

Assessing trophic relations with detailed stomach contents analysis increases knowledge on suitable stock-recruit models, assessment of fish species (e.g. estimates of Natural Mortality) and reliable Biological Reference Points (BRP) considering species interactions, all aiming at providing a more appropriate framework for the implementation of multi-annual management plans. 

So far, there is no regularly conducted stomach sampling programme covering the entire North Sea, including the Skagerrak and Kattegat, and the FishPi project (EU MARE/2014/19) concluded that the lack of coordination in different stomach sampling campaigns leads to unbalanced sampling effort resulting in a lack of statistically sound sampling of all key species needed for food web characterisation and finally to a barrier for moving towards an Ecosystem Approach to Fisheries (EAF).  

Consequently, the intersessional subgroup for the regionally coordinated stomach sampling was established to improve this situation. The main aim and purpose of this group is the development, implementation and coordination of a regionally coordinated stomach sampling plan in the North Sea, Skagerrak and Kattegat. 

This sampling programme has started in 2022 through a coordinated stomach sampling campaign during the North Sea International Bottom Trawl Survey (IBTS) in quarters 1 and 2 and this group will work on the further establishment of this programme and a subsequent stomach content analysis and coordination system. 

Chairs: Pierre Cresson (FRA), Matthias Bernreuther (DEU)



14 ISSG Regionally Coordinated Stomach Sampling; in: 

RCG NA NS&EA RCG Baltic 2022. Regional Coordination Group North Atlantic, North Sea & Eastern Arctic and Regional Coordination Group Baltic. 2022. Part III, Intersessional Subgroup (ISSG) 2021-2022 Reports, 159 pgs.   

Recreational Fisheries 

Recreational fisheries data is collected by individual Member States (MS) according to the Basic Regulation (EU) No 1380/2013 and the multiannual data collection framework (EU) 2016/1251. However, there is no standardization between countries and in general there is no one-size fits all approach due to the diverse nature of the sector and cultural differences. Challenges in recreational fisheries data collection are data gaps (no data collected), periodicity of surveys (no time series), and single instead of multispecies surveys. Also often lacking is economic and social data to evaluate the sectoral contribution and ensure fisheries are ecologically, economically, and socially sustainable. 

ISSG Recreational Fisheries was established in 2021, because the RCG NANSEA and RCG Baltic needed progress with regional sampling plans for Marine Recreational Fisheries (MRF). The EU-MAP states the relevance of the regional approach for these fisheries, including evaluating end users’ needs for biological data collection, coordinating national surveys of recreational fishing, and defining potential thresholds. As the new regulation does not have a pre-defined list of species, it will be determined by region based on end-user needs. ISSG Recreational Fisheries aims to harmonize recreational fisheries data collection particularly on a regional level. For this subgroup to work properly, it is needed to ensure that the right people are involved, including experts from WGRFS, DCF, and PGECON. National Correspondents (NC) need to be approached to ensure that relevant bodies are contacted to ensure expert participation. 

This ISSG aims to fit on preparatory work for decision making, including input for Regional Work Plans (RWPs). The ISSG Recreational Fisheries coordinates with the relevant ICES EG (WGRFS) and the Fishn’Co consortium. ISSG Recreational Fisheries focuses on defining a species list at a regional level, working on regional sampling plans for shared stocks, and incorporating MRF data in the RDBES. 

Chairs: Harry V. Strehlow (DEU) 



13 ISSG Marine Recreational Fisheries; in: 

RCG NA NS&EA RCG Baltic 2022. Regional Coordination Group North Atlantic, North Sea & Eastern Arctic and Regional Coordination Group Baltic. 2022. Part III, Intersessional Subgroup (ISSG) 2021-2022 Reports, 159 pgs.  

Metier and transversal variables issues 

The group has been ongoing since 2018, starting with a workshop discussing the methods used to assign métier codes to transversal data, issues and best practices, and the following years as an RCG ISSG. Since 2021, the group changed name to ‘ISSG on Métier and transversal variables issues”, also including tasks related to the definition and calculation of transversal variables dealing with issues and best practices. The group manages a list of métier codes and reference lists used for assigning the metiers. 

Chairs: Josefine Egekvist (DNK), Sébastien Demanèche (FRA)



RCG (2018) DCF Métier Workshop, Lyngby, Denmark, 22-26 January 2018. A DCF ad-hoc workshop. Sub-group of the RCGs – North Sea and Eastern Arctic and North Atlantic. 87pp. 

European Commission, Joint Research Centre, Calvo Santos, A., Pinnelo, D., Ioannou, M., et al., Report on the 2nd workshop on transversal variables : Nicosia, Cyprus, 22-26 February 2016 : a DCF ad-hoc workshop, Holmes, S.(editor), Scott, F.(editor), Castro Ribeiro, C.(editor), Publications Office, 2016, 

Workshop reports – European Commission ( 

Joint Research Centre, Institute for the Protection and Security of the Citizen, Report on the workshop on transversal variables : (Linking economic and biological effort data (call) design), 19th -23rd January 2015, Castro Ribeiro, C.(editor), Publications Office, 2015, 

Workshop reports – European Commission ( 

RCG (2022) ISSG Métier and transversal variable issues, 2022 report. 25pp. 

RCG (2021, 2020 & 2019) ISSG on Métier issues, 2021, 2020 & 2019 report. 

CS small pelagics Baltic

RCG Baltic agreed to use the fisheries for small pelagic species as a case study for the development of a regional sampling programme in the Baltic Sea. It was agreed to establish a subgroup for in-depth analyses how a regional sampling programme for small pelagics can be established and suggest how it can be implemented. The pelagic fisheries target western Baltic herring, central Baltic herring, herring in Gulf of Bothnia, herring in Gulf of Riga and sprat.

Implementation of regional schemes frequently gets bogged down by single alternatives, or is stopped because of national interest not being prioritized in the regional context. However, this group sees regionalization is a process that can have several outcomes, and it is not necessary the final goal to have a 100% common approach (same vessel platform etc.) for a regionalization to be fulfilled.

The subgroup considers regionalization as involving 4 general steps located along a gradient that goes from “no coordination” to “common monitoring strategy” and “joint data collection”. This gradient naturally entails a different capability of sampling to meet the needs of national and regional end-users. To supplement the sampling needs of specific end-users (e.g., specific end-uses), part of the program can be left for planning on a national scale. That part can still be coordinated (e.g., have common protocols) but does not necessarily require the higher level of regional coordination involved in full regional sampling plans.

Chairs: Marie Storr-Paulsen (DNK), Katja Ringdahl (SWE)

Involved RCG: RCG Baltic

Regional Work Plan

During 2022, RCG NANSEA and RCG Baltic agreed to revive the ISSG on the Development of Regional Workplan (ISSG RWP) during the period 2022-23. The ISSG RWP was given the mandate to develop Draft Regional Work Plan for the period 2025-2027 taking over the Fishn’Co and Streamline projects and then follow-up on the RWP development from 2023 onward. The Liaison Meeting 2023 recommended that the scope of the ISSG RWP was pan regional.

Chairs: Joël Vigneau (FRA), Maria Hansson (SWE), Alessandro Ligas (ITA)



6. ISSG on Development of Regional Work Plan, in: RCG NANS&EA RCG Baltic 2023. Regional Coordination Group North Atlantic, North Sea & Eastern Arctic and Regional Coordination Group Baltic. 2022. Part III, Intersessional Subgroup (ISSG) 2022-2023 Reports, 320 pgs.


The ISSG National Correspondents (ISSG NC) was first established in 2020, as an initiative of the RCGs NANSEA and Baltic. National correspondents from NANSEA and Baltic Member States are the participants of this group.

One of the first tasks of the ISSG NC was to amend the rules of procedure (RoPs) for the RCG NANSEA and RCG Baltic, since both RCGs decided to hold their annual meetings back-to-back. As a result, RCG NANSEA and RCG Baltic have combined RoPs.

Over the years the group has assessed the viability of making the ISSG NC work more pan regional to address issues like the long-term funding of the RCGs Secretariat. In order to make the ISSG work more pan regional the group liaises between different RCGs, and national correspondents from other Member States outside NANSEA and Baltic areas are invited to discussions when needed.

Chair: Anna Hasslow (SWE)

RCGs involved: RCG NANSEA, RCG Baltic


16. ISSG National correspondents, in: RCG NANS&EA RCG Baltic 2023. Regional Coordination Group North Atlantic, North Sea & Eastern Arctic and Regional Coordination Group Baltic. 2022. Part III, Intersessional Subgroup (ISSG) 2022-2023 Reports, 320 pgs.