French Research Institute for Exploitation of the Sea
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Ecological Roles of Mesopelagic Micronekton in the Northeast Atlantic: A Trait-Based Perspective
No full textTowards uniform metrological processes for the characterization and analysis of microplastics?
No full textConvention MTE – Ifremer. Compte-rendu de fin d’exécution – 31/12/2024
No full textBilan de fin d'exécution de la convention n° 24/1004714 entre le ministère en charge de l'environnement (MTE) et l'Ifremer au 31 décembre 202
Establishing a comprehensive host-parasite stable isotope database to unravel trophic relationships
No full textOver the past decades, stable isotopes have been infrequently used to characterise host-parasite trophic relationships. This is because we have not yet identified consistent patterns in stable isotope values between parasites and their host tissues across species, which are crucial for understanding host-parasite dynamics. To address this, we initiated a worldwide collaboration to establish a unique database of stable isotope values of novel host-parasite pairs, effectively doubling the existing data in published literature. This database includes nitrogen, carbon, and sulphur stable isotope values. We present 3213 stable isotope data entries, representing 586 previously unpublished host-parasite pairs. Additionally, while existing literature was particularly limited in sulphur isotope values, we tripled information on this crucial element. By publishing unreported host-parasite pairs from previously unsampled areas of the world and using appropriate host tissues, our dataset stands unparalleled. We anticipate that end-users will utilise our database to uncover generalisable patterns, deepening our understanding of the complexities of parasite-host relationships and driving future research efforts in stable isotope parasitology
Copernicus Marine In Situ TAC. Quality Control Procedure
No full textThis document specifies the additional quality control procedures performed by Copernicus Marine In Situ TAC before distributing ocean in situ data and metadata. This procedure follows the recommendations endorsed in 2010 by the EuroGOOS data-meq working group completed by the regional expertise of the Copernicus Marine In Situ TAC data scientist
Barriers to Effective Management of Mediterranean Coastal Lagoons Following Key European Union Directives: Perceptions of Managers of Natura 2000 Lagoon Sites in South France
No full textThis paper focuses on the challenges for the co-implementation of two European Union Directives, i.e., the Habitats Directive and the Water Framework Directive, for the management of Mediterranean coastal lagoons as protected areas. Many of these ecosystems are included in the Natura 2000 network, the largest network of protected areas in the world. Based on semi-structured interviews with 45 stakeholders from 41 institutions, the study identified five main types of perceived barriers: economic, political and socio-cultural, historical, administrative, and ecological. The study confirmed that the co-implementation of the Habitats Directive (HD) and the Water Framework Directive (WFD) in Mediterranean coastal lagoons generated multiple and interrelated barriers. Beyond their regulatory complexity, these EU directives confronted managers with deep operational challenges. First, mismatches between administrative and ecological boundaries weakened their ability to control key ecological processes such as nutrient flows. Second, the proliferation of indicators, often perceived as disconnected from local realities, reinforced the critique of a management by numbers approach. Finally, the widespread use of regulatory exemptions, while intended to adapt EU rules to local contexts, frequently fueled persistent mistrust among stakeholders, especially in historically degraded environments. These challenges were further exacerbated by a siloed organization of administrations, limiting coordination and adaptive management. Overall, these findings call for more integrated governance frameworks, a more critical and context-sensitive use of indicators, and greater transparency in derogation procedures
Exploring the regional diversity of eukaryotic phytoplankton in the English Channel by combining high-throughput approaches
No full textMonitoring marine phytoplankton is essential to understanding marine ecosystems functioning, especially in productive regions like the English Channel. This study applied high-throughput sequencing (HTS) and automated pulse shape-recording flow cytometry (PSR FCM) to investigate the spatial and seasonal variability of phytoplankton diversity in French waters of the English Channel during the ECOPEL cruises in April (spring) and July (summer) 2018. Our findings revealed significant seasonal shifts in size, structure, total red fluorescence (FLR, a biomass proxy) and community composition. PSR FCM provided high-resolution size class discrimination, revealing an increase in picoeukaryote abundance and lower FLR in summer compared to spring. HTS enabled detailed taxonomic insights: in spring, picoeukaryotes (e.g. Ostreococcus) dominated in the Western English Channel, except in Finistère/Celtic Seas, where microphytoplankton represented the majority of reads. Nanoeukaryotes ( Phaeocystis) dominated in the Eastern English Channel. In summer, diversity increased, with co-dominance of picoeukaryotes ( Micromonas, Bathycoccus, Ostreococcus), microphytoplankton ( Chaetoceros, Leptocylindrus, Guinardia) and nanoeucaryotes ( Teleaulax, Gephyrocapsa) in the Bay of Seine. Beyond a pronounced west-east disparity, the Bay of Seine exhibited remarkable taxonomic and functional diversity, with high local contribution to beta diversity (LCBD) values in both seasons. Diversity patterns were strongly influenced by temperature and nutrient concentrations (phosphate, nitrogen), with secondary influences from salinity and turbidity. PSR FCM further revealed sub-mesoscale variability in abundance and size structure, complementing the mesoscale patterns observed through HTS. This study highlights the importance of integrating both methods to capture fine-scale phytoplankton dynamics and high-resolution diversity, thereby enhancing ecosystem management, espcecially in nutrient-sensitive, productive marine regions
Elasmobranch vulnerability to global warming: insights from bioenergetic modelling of catsharks under climate scenarios
No full textEctotherms are especially vulnerable to global warming due to their temperature-sensitive metabolic processes, impacting survival and reproductive success. Elasmobranchs, with slow life histories and low reproductive rates, may face amplified risks. In this study, we investigated two catshark species with distinct life traits and distributions: the Small-spotted Catshark (Scyliorhinus canicula) and the Nursehound (S. stellaris). Using newly calibrated bioenergetic models, we assessed changes in growth, sexual maturity, offspring production, and population dynamics under two CMIP6 climate scenarios projected for 2100: SSP2–4.5 (Middle of the Road) and SSP5–8.5 (Fossil-fueled Development), comparing these to historical data (1994–2015). Survival rates for early life stages remained similar under historical temperatures (80 %) and SSP2 (83 %) but dropped sharply under SSP5 to 33 % for S. canicula and 23 % for S. stellaris. Under both SSP2 and SSP5, S. canicula showed slight delays in maturation, yet the proportion of mature individuals ultimately exceeded historical levels in SSP2. Conversely, S. stellaris experienced progressively delayed maturation with warming. In SSP5, reduced growth, reproduction, and survival caused a population crash for S. stellaris, suggesting potential extinction. Our results reveal contrasting climate impacts on these species, underscoring the risk for late-maturing, low-fecundity, and narrowly distributed species. This emphasizes the urgency of conservation strategies tailored to mitigate their vulnerability to global warming
Reliance and Usage of Anchored Fish Aggregating Devices (Afads) in the Indonesian Tuna Fisheries
No full textThe development of tuna fisheries in the Indian Ocean is closely linked to the use of Fish Aggregating Devices (FADs). While FADs increase fishing efficiency, their sustainability raises concerns. Information on FAD utilization, particularly in Indonesia, remains limited. This study investigates Indonesia's anchored FADs tuna fisheries through a semi-structured survey of 293 tuna fishers using FADs in eight major Indonesian fishing ports in the Indian Ocean. With the exception of one group of handline vessels that use lights to attract tuna and operate at night, all other groups (purse seiners, troll-line, and handline vessels) utilize aFADs in over 90% of their tuna-targeted fishing operations. All aFADs were reported to be privately owned, either by vessel captains, vessel owners, fishing associations, or companies, with aFAD sharing primarily occurring within the same aFAD ownership group. On average, vessels or group of vessels owned between 1 aFAD (hook and line vessels) to 8 aFADs (purse seiners). aFAD arrays reported by respondents, showed an average of 4-5 aFADs within 10 nm of the aFADs they utilize. Long aFAD lifetimes (2-4 years on average) indicated the skilled knowledge of fishers in using and maintaining these devices. Interestingly, the number of aFADs visited by fishing vessels was not correlated with the trip duration and remained relatively low (< 16 aFADs visited for all vessels). This suggests that vessels tend to exploit the same aFAD array throughout their trip, even when it lasts several months. Landing data supported these findings and revealed seasonal patterns in aFAD use, including partial shifts in target species for hook and line vessels. The findings of this study are expected to provide quantitative insights and contribute to the management of tuna FAD fisheries in Indonesia and the Indian Ocean
Workshop on Management Strategy Evaluation for North Sea Herring (WKMSEHerring)
No full textThe European Union, Norway, and the United Kingdom jointly requested ICES to identify appropriate combinations of Ftarget and Btrigger in a harvest control rule that, together with possible TAC constraints, could form part of a long-term management strategy for North Sea autumn spawning herring (Clupea harengus) in Subarea 4 and divisions 3.a and 7.d, (North Sea, Skagerrak and Kattegat, eastern English Channel). A Management Strategy Evaluation (MSE) process was set up to evaluate such combinations, check that the management strategy was robust to a 10% banking and borrowing mechanism, and to investigate sensitivity to a number of exploitation pattern scenarios. Key sources of uncertainty (related to recruitment and natural mortality) were captured by a reference set of operating models, and results were integrated over these. Key findings are that several management strategies are possible for a similar level of precaution (less than 5% risk), with similar levels of catch (less than 5% difference in average yield between the possible rules). These different rules involve either a high Ftarget and high Btrigger, or a lower Ftarget combined with a lower Btrigger, and provide a trade-off between maximising catch and minimising interannual variability in catch. However, a high Ftarget-high Btrigger combination (e.g. Ftarget=0.34, Btrigger=1.7 million tonnes) results in a marginally higher yield (average annual catch of 0.37 million tonnes) but with a realised fishing mortality well below Ftarget (0.23 against Ftarget=0.34) because such high theoretical Ftarget rules result in the stock being frequently below the Btrigger value. This combination of control points are also associated with more unstable catches (IAV=18.5%), lower SSB (1.3 million tonnes), and the more frequent suspension of TAC constraints (as a result of SSB being below Btrigger). In contrast, a low Ftarget-low Btrigger combination (e.g. Ftarget=0.21, Btrigger=0.8 million tonnes) results in marginally lower yield (average annual catch of 0.36 million tonnes) but with realised fishing mortality close to Ftarget (0.2 against Ftarget=0.21), substantially more stable catches (IAV=9.9%), higher SSB (1.5 million tonnes), and less frequent suspension of any stability mechanisms in place. Assuming current fishing conditions (2022-3), as opposed to longer-term recent (2013-2021) or historical (1998-2003) conditions, leads to higher risk and more variable fishing mortality on ages 0-1, providing assurance that assuming current conditions (as was adopted for the reference set of operating models) is both reasonable and errs on the side of precaution with respect to risk. Increasing fishing mortality on ages 0-1 has a clear negative impact on risk, SSB and catch in the long-term. Furthermore, shifting the selection pattern towards younger ages is generally negative across all performance metrics. Management strategies appear to be robust to implementing a 10% banking and borrowing scheme, even under an extreme version that deliberately forces unrealistic annual fluctuations in catch (the opposite of its intended purpose). It should be stressed that Ftarget and Btrigger selected from the MSE should not be confused with reference points set by ICES and should not be used to indicate stock status