Analysis and optimisation of assessments/diagnostics concerning cephalopod stocks exploited by the French fleet in the Atlantic
CONTEXT
The MERSEA laboratory at the University of Caen Normandy is a European pioneer in applying exploited population dynamics models to Cephalopod stocks (cuttlefish and squid) and in studying the ecology of these fisheries. The results from six defended theses have provided, among other things, the first European stock assessments (Royer et al., 2002, 2006) and the first analyses of stock-recruitment relationships (Challier et al., 2005; Gras et al., 2014).
Assessments concerning cuttlefish and squid in the English Channel and the Bay of Biscay were initially obtained through the Interreg Ceph&Chefs project, which included fitting surplus production models using the R package SPiCT (Surplus Production in Continuous Time) (Pedersen et al., 2017; ICES, 2020). These evaluations were updated in 2023 and 2024 under an agreement with the DGAMPA (Direction Générale des Affaires Maritimes de la Pêche et de l’Aquaculture), which has since been extended by an agreement for access to the necessary French data.
Cuttlefish (Sepia officinalis) and Loliginid squid are shared resources (in the English Channel with the Belgian, Dutch, and UK fleets; in the Bay of Biscay with Spain). These stocks are not managed at the community level by TACs and Quotas. They are nevertheless valuable resources, generating, for example, an annual revenue of approximately €20 million each in the English Channel (for all countries combined), and ranking 3rd and 5th in value for Norman fisheries (Ifremer, 2024).
Cephalopods have unique biological characteristics: a short lifespan, very rapid growth, migrations, and death after a single reproduction (semelparity), which distinguishes them from fish and justifies the use of “DLS” approaches (for Data-Limited Stocks). They are also resources sensitive to environmental variations (Rodhouse et al., 2014) that exhibit large interannual fluctuations in abundance or biomass, raising questions about the relevance of “long-term average” reference points (Roa-Ureta et al., 2021).
Recent analyses (Marcout et al., 2025) and access to OBSMER program data make it possible to assess fishing pressure on each of the two exploited squid species in the English Channel (Loligo forbesii and Loligo vulgaris). Furthermore, the evolution of squid catches by the countries bordering the North Sea suggests an extension of the fishing zone from the Eastern Channel to the Southern North Sea. This change in scale for the assessment of this resource is being prepared in collaboration with Belgian, Dutch, and British fisheries scientists. Finally, it is also desirable to attempt to take into account the effect of the environment on the natural increase in biomass using existing tools.
INTERNSHIP OBJECTIVES
- To analyse the results of the 2025 assessments in light of the ‘ICES technical guidance for harvest control rules and stock assessments for stocks in category 2 and 3’ guide and prepare the update of the 2026 assessments (integrating 2025 data).
- For squid, to use data from the Obsmer program for separate assessments of each species (Loligo forbesii and Loligo vulgaris).
- For squid in the English Channel and the Southern North Sea, to take into account the extension of the fishery and conduct an assessment of the ‘extended’ stock using data from the different countries.
- To prepare the communication of these assessments to the expert group (ICES-WGCEPH) as well as to representatives of the professionals (CRPMEM, OP)
REQUIRED PROFILE
- Second year of Master’s degree, or end of an engineering cycle in marine sciences, fisheries science, marine ecology, biological oceanography, or modeling.
- Particular interest in the modeling of populations exploited by fishing.
- Proficiency in the R programming language, RMarkdown, and GitHub.
- Communication skills at various levels (scientists, managers, fishermen)
APPLICATION INFORMATION
Applications (cover letter and CV/resume) must be sent by email to Jean-Paul Robin (jean-paul.robin@unicaen.fr) by midnight on December 15, 2025.