14 research outputs found

    Evaluating the effectiveness of management measures on skates in a changing world

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    Global declines in elasmobranchs have been observed. Conservation measures such as area closures and fisheries prohibitions have been put in place to support the recovery of vulnerable species. However, the effectiveness of such measures is rarely evaluated in the context of other factors that may affect population abundance. This study investigates the effectiveness of management measures using 1) General additive mixed model derivative changes, taking into account environmental factors that may affect population stochasticity and 2) an age-structured density dependent population dynamic model. The Raja undulata (undulate ray) 2009 targeted fisheries prohibition was used as a case study. Potential beneficial responses on sympatric species Raja clavata (thornback ray) were modelled. A significant increase in abundance was observed in both IUCN red list species during the ban. Surface seawater temperature had a marginal effect on the abundance of both species. The prohibition was in place for an insufficient length of time for long lasting effects to be detected on skate length. The population dynamic model indicated that the increase in abundance was only possible when combining the fisheries ban with increased juvenile discard survival. Our results indicate that species conservation measures may not only have positive effects on the species in question, but also on species with a niche overlap. Nonetheless, due to ongoing fishing for other species, the full potential of fisheries prohibitions may not be realised. For real benefits to be assessed, evaluation of bans should take place once a steady state is observed

    Benchmark Workshop on selected stocks in the Western Waters in 2021 (WKWEST).

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    The goal of a benchmark is consensus agreement on an assessment methodology that is to be used in future update assessments. This assessment methodology can be an analytical assessment, but can also be non-analytical, for instance based on trends in an assessment or in a selected set of (survey) indicators, with or without forecasts. The result will be the 'best available' method that ICES advice will be based on. WKWEST 2021 dealt with the following stocks: Sardine (Sardina pilchardus) in Subarea 7 (southern Celtic Seas, and the English Channel); Pollack (Pollachius pollachius) in subareas 6-7 (Celtic Seas and the English Channel); Red gurnard (Chelidonichthys cuculus) in subareas 3–8 (Northeast Atlantic); Plaice (Pleuronectes platessa) in divisions 7.h–k (Celtic Sea South, southwest of Ireland); Sole (Solea solea) in divisions 8.c and 9.a (Cantabrian Sea and Atlantic Iberian waters)

    Management for sustainable cephalopod fisheries in Europe: review and recommendations

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    Although cephalopod fisheries are of world-wide importance, in Europe catching cephalopods is managed only in small-scale fisheries, at national level, and few stocks are formally assessed. Because cephalopods are not quota species under the EU’s Common Fisheries Policy, there is currently no requirement for assessment or management at European level. Given increasing interest in targeting cephalopods in Europe, there is a risk that they will be fished unsustainably. Although there have been recent review papers on progress in stock assessment and fishery forecasting for commercially fished cephalopods there has been no recent review of cephalopod fishery management. We aim to fill this gap, with a particular focus on European cephalopod fisheries.We review potential barriers to sustainable fishing and reasons why management of cephalopod fisheries differs from that for finfish fisheries, e.g. due to the high inherent volatility and the possibly cyclic nature of year-to-year variation in cephalopod abundance, reflecting their short lifespan, rapid growth and high sensitivity to environmental conditions. We review fishery management approaches in important cephalopod fisheries worldwide (e.g. in the USA, Japan, Falklands, South Africa, Australia and Russia) and current management of small-scale cephalopod fisheries in Europe. We identify knowledge gaps and limitations to current monitoring programmes and stock assessments and discuss the options available for cephalopod fishery management in Europe, considering the suitability or otherwise of catch and effort limits, use of closed areas and seasons, restrictions on sizes caught and types of fishing gear, and the ole of market-based sustainability pathways.info:eu-repo/semantics/publishedVersio

    Working group on cephalopod fisheries and life history (Wgceph; outputs from 2022 meeting)

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    Rapports Scientifiques du CIEM. Volume 5, nº 1WGCEPH worked on six Terms of Reference. These involved reporting on the status of stocks; reviewing advances in stock identification, assessment for fisheries management and for the Ma- rine Strategy Framework Directive (MSFD), including some exploratory stock assessments; re- viewing impacts of human activities on cephalopods; developing identification guides and rec- ommendations for fishery data collection; describing the value chain and evaluating market driv- ers; and reviewing advances in research on environmental tolerance of cephalopods. ToR A is supported by an annual data call for fishery and survey data. During 2019–2021, com- pared to 1990–2020, cuttlefish remained the most important cephalopod group in terms of weight landed along the European North Atlantic coast, while loliginid squid overtook octopus as the second most important group. Short-finned squid remained the least important group in land- ings although their relative importance was almost double in 2019–2022 compared to 1992–2020. Total cephalopod landings have been fairly stable since 1992. Cuttlefish landings are towards the low end of the recent range, part of a general downward trend since 2004. Loliginid squid landings in 2019 were close to the maximum seen during the last 20 years but totals for 2020 and 2021 were lower. Annual ommastrephid squid landings are more variable than those of the other two groups and close to the maximum seen during 1992– 2021. Octopod landings have generally declined since 2002 but the amount landed in 2021 was higher than in the previous four years. Under ToR B we illustrate that the combination of genetic analysis and statolith shape analysis is a promising method to provide some stock structure information for L. forbsii. With the sum- mary of cephalopod assessments, we could illustrate that many cephalopod species could al- ready be included into the MSFD. We further provide material from two reviews in preparation, covering stock assessment methods and challenges faced for cephalopod fisheries management. Finally, we summarise trends in abundance indices, noting evidence of recent declines in cuttle- fish and some octopuses of the genus Eledone. Under ToR C, we describe progress on the reviews of (i) anthropogenic impacts on cephalopods and (ii) life history and ecology. In relation to life history, new information on Eledone cirrhosa from Portugal is included. Under ToR D we provide an update on identification guides, discuss best practice in fishery data collection in relation to maturity determination and sampling intensity for fishery monitoring. Among others, we recommend i) to include the sampling of cephalopods in any fishery that (a) targets cephalopods, (b) targets both cephalopods and demersal fishes or (c) takes cephalopods as an important bycatch, ii) Size-distribution sampling, iii) the use of standardized sampling pro- tocols, iv) an increased sampling effort in cephalopod. Work under ToR E on value chains and market drivers, in conjunction with the Cephs & Chefs INTERREG project, has resulted in two papers being submitted. Abstracts of these are in the report. Finally, progress under ToR F on environmental tolerance limits of cephalopods and climate en- velope models is discussed, noting the need to continue this work during the next cycle.info:eu-repo/semantics/publishedVersio

    Projet Accobiom (ACquisition de COnnaissances sur les paramètres BIologiques des ressources marines exploitées en Outre-Mer). Retour d’expérience antillais

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    Ce document est un bilan de la mise en oeuvre du projet déployé en Guadeloupe et en Martinique. Il identifie les éléments fonctionnels ainsi que les freins potentiels au regard des objectifs fixés et des moyens mis à disposition. A terme, le but est la poursuite de la collecte des données sur les principales espèces commercialisées aux Antilles portant sur l’identification précise des compositions spécifiques, les mensurations des individus (longueurs et poids), le sexe et potentiellement la maturité sexuelle ainsi que la détermination de l’âge par sclérochronologie

    Morphometric Relationships between Length and Weight of 109 Fish Species in the Caribbean Sea (French West Indies)

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    In total, 109 fish species (24,996 individuals)were sampled around Guadeloupe andMartinique Islands from October 2021 to September 2022 to estimate the morphometric relationships between total length and weight (LengthWeight Relationship: LWR) of each fish species according to potential spatial, temporal and sex differences. Of these species, this is the first time that the LWR was estimated in the Atlantic Ocean for 16 species. There is a significant relationship between length and weight for all tested species. For 83 tested species, the sex effect on the LWR showed significant sexual dimorphism for 24 species. Additionally, a link between the temporal effect and the reproduction period was tested for 68 species, of which 35 presented significant differences relative to the annual quarter of sampling. Finally, the geographical effect (i.e., the difference between samples from around Guadeloupe Island and those fromMartinique Island) was significant for 60 species. This island effect was significant for 25 species

    Multi-method approach shows stock structure in Loligo forbesii squid

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    International audienceKnowledge of stock structure is a priority for effective assessment of commercially-fished cephalopods. Loligo forbesii squid are thought to migrate inshore for breeding and offshore for feeding and long-range movements are implied from past studies showing genetic homogeneity in the entire neritic population. Only offshore populations (Faroe and Rockall Bank) were considered distinct. The present study applied mitchondrial and microsatellite markers (nine loci) to samples from Rockall Bank, north Scotland, North Sea, various shelf locations in Ireland, English Channel, northern Bay of Biscay, north Spain, and Bay of Cadiz. No statistically significant genetic sub-structure was found, although some non-significant trends involving Rockall were seen using microsatellite markers. Differences in L. forbesii statolith shape were apparent at a subset of locations, with most locations showing pairwise differences and statoliths from north Ireland being highly distinct. This suggests that (i) statolith shape is highly sensitive to local conditions and (ii) L. forbesii forms distinguishable groups (based on shape statistics), maintaining these groups over sufficiently long periods for local conditions to affect the shape of the statolith. Overall evidence suggests that L. forbesii forms separable (ecological) groups over short timescales with a semi-isolated breeding group at Rockall whose distinctiveness varies over time
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