Ices Wgef 2020

Amelot, Morgane; Barreau, Thomas; Baulier, Loïc; Biais, Gerard; Bleeker, Katinka; Díez, G.; Figueiredo, Ivone; Jakobsdóttir, Klara B.; Johnston, Graham; Jung, Armelle; Junge, Claudia; Myrlund, Marlén Knutsen; Lleal, Wendel; Maia, Catarina; Miethe, Tanja; Moura, Teresa; Oliveira, José De; Schaber, Matthias; Batsleer, Jurgen; Lorance, Pascal

doi:10.17895/ices.pub.7470

Cited by 7 publications

(6 citation statements)

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“…The GLM was run using the lsmeans R package [70]. Statistical details on this estimate are given by ICES WGEF [16].…”

Section: Catch Rates and Landingsmentioning

confidence: 99%

“…In the Azores, genetic studies support the existence of a self-contained R. clavata population, i.e., a stock unit for which it is assumed that abundance dynamics are determined by internal processes of recruitment and mortality, and insignificantly affected by immigration and emigration [14,15]. Raja clavata in the Azorean region represents more than 90% of the landed skates [16], and it is mainly caught by the demersal fishery using hook and lines [17]. Catch trends of this species have declined steeply from 171 t (5.6 kg 10 −3 hooks) in 2015 to 70 t (3.1 kg 10 −3 hooks) in 2017 [9].…”

Section: Introductionmentioning

confidence: 99%

“…No information on the discard rates of skates is available for recent years. Nevertheless, discarding is known to take place, and is the result of management measures, particularly the total allowable catches-TACs/quotas, minimum size, and fishing area restrictions rather than the complete lack of a market [9,16,18]. On the other hand, previous studies have reported that the discard survival of skate species is high [19][20][21][22], particularly for R. clavata caught by longline fishing [9,23].…”

Section: Introductionmentioning

confidence: 99%

“…Currently, the International Council for the Exploration of the Sea (ICES) assesses the R. clavata from the Azores based on a precautionary approach because of the data quality (ICES stock category 3; [16]). There is poor knowledge of the biology of the species for this ecoregion and available information is uncertain.…”

Section: Introductionmentioning

confidence: 99%

“…The abundance index derived from the Azorean bottom longline survey [24] is used as an index of stock development; however, stock status relative to reference points is unknown [25]. Considering this, the ICES working group on elasmobranch fishes (WGEF) recommends that further studies should be conducted to define the appropriate set of life-history parameters and describe the population dynamics in order to provide more accurate data for exploratory assessments [16].…”

Section: Introductionmentioning

confidence: 99%

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Biological Knowledge of Thornback Ray (Raja clavata) from the Azores: Improving Scientific Information for the Effectiveness of Species-Specific Management Measures

Santos

Medeiros‐Leal

Novoa‐Pabon

et al. 2021

Biology

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Elasmobranchs are globally recognized as vulnerable due to their life-history characteristics, fishing pressure, and habitat degradation. Among the skates and rays caught by commercial fisheries, the thornback ray Raja clavata is one of the most economically important in Northwest European seas. However, the scarcity of biological knowledge about this species in Azorean waters has limited the stock assessment types that can be conducted. To improve information on its habitat preferences, spatial distribution and movement pattern, growth, sex ratio, mortality, and reproduction, as well as to investigate long-term changes in abundance and size, this study analyzed approximately 25 years of fishery-dependent and independent data from the Azores. Raja clavata was mainly caught at depths up to 250 m. Most of the tagged fish were recaptured near the release point. A larger–deeper trend was found, and females were larger and more abundant than males. Life-history parameters showed that R. clavata has a long lifespan, large size, slow growth, and low natural mortality. The sustainability of its population is of concern to fisheries management and, while our findings suggested a relatively healthy stock in the Azores, a thorough increase in data quality is required to better understand the stock condition and prevent overexploitation.

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“…The GLM was run using the lsmeans R package [70]. Statistical details on this estimate are given by ICES WGEF [16].…”

Section: Catch Rates and Landingsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Biological Knowledge of Thornback Ray (Raja clavata) from the Azores: Improving Scientific Information for the Effectiveness of Species-Specific Management Measures

Santos

Medeiros‐Leal

Novoa‐Pabon

et al. 2021

Biology

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First report of an egg nursery for the Critically Endangered flapper skate Dipturus intermedius (Rajiformes: Rajidae)

Dodd¹,

Baxter

Donnan³

et al. 2022

Aquatic Conservation

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1. This study provides the first report of an egg nursery for the Critically Endangered flapper skate Dipturus intermedius and a description of the habitat, thus contributing towards our understanding of essential habitats for the species. 2. In total, 1,395 flapper skate egg cases were recorded (accounting for overlapping surveys) in two egg case collection dives (n = 67 egg cases), one photogrammetry dive (n = 10 egg cases), 509 drop-down video (DDV) camera drifts (n = 510 egg cases) and 18 remote operated vehicle (ROV) flights (n = 1,031 egg cases), carried out in the Inner Sound on the west coast of Scotland from 2018 to 2021. All of the egg cases were found on a shallow bedrock plateau between the Isle of Scalpay and a deep (>100 m) water channel between the Isle of Longay and the Crowlin Islands. Egg cases were observed on a cobble/boulder reef between 25 and 58 m depth, with a modelled annual temperature range of 9-12 C, modelled current speeds up to 0.2 m À1 , a rugosity index of 1.7 and low levels of sedimentation.3. Flapper skate egg cases are large and the incubation period is protracted (18 months), making them potentially vulnerable to anthropogenic disturbance.A description of the habitat where egg cases were observed in this study will help inform the search for egg nurseries for this Critically Endangered species elsewhere. Targeted DDV, ROV and scuba diving surveys will support this search in areas where suitable bathymetric and hydrodynamic conditions are identified.4. Safeguarding egg nurseries is essential for successful conservation. Protection should involve the designation of egg nurseries as Marine Protected Areas where activities that are likely to damage or alter seabed habitats are managed.

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Life-history traits of batoids (Superorder Batoidea) in the Northeast Atlantic and the Mediterranean

Villagra

Bogaert

Ampe

et al. 2022

Rev Fish Biol Fisheries

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Life-history traits provide a way to estimate the vulnerability of both individuals and populations of a species to disturbance (e.g., overexploitation, climate change). Life-history traits compilations for species of batoids in the Northeast Atlantic (NEA) and the Mediterranean Sea (MED) are scarce, outdated, and generally limited to a local or a regional scale. A literature review compiling values of 10 life-history traits describing the growth, reproductive and feeding strategies of 14 batoids in the NEA and the MED was performed. Via a principal components analysis (PCA) the main drivers of variance and (groups of) similar species were identified. Significant data gaps were revealed for natural mortality and lifespan, for most of the life-history traits of small-eyed (Raja microocellata), shagreen (Leucoraja fullonica), and sandy (Leucoraja circularis) ray, and specifically for the English Channel and Bay of Biscay. The common skate complex (Dipturus batis complex) and white (Rostroraja alba) skate were found to be different from the rest of the species due to their larger sizes, relatively slow growth, and late maturity, which may make them more vulnerable to overexploitation, while the Raja spp. and Leucoraja spp. rays tend to be smaller species growing at faster rates. Growth and reproductive life-history should be considered as vulnerability to disturbance proxies, be used to update/establish management measures (i.e. minimum size) and enhance the stock assessment predictive ability (i.e. length based-indicators). Future research should be directed towards filling important regional data gaps and providing robust estimation for unreported parameters, such as natural mortality.

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Ices Wgef 2020

Cited by 7 publications

References 0 publications

Biological Knowledge of Thornback Ray (Raja clavata) from the Azores: Improving Scientific Information for the Effectiveness of Species-Specific Management Measures

Biological Knowledge of Thornback Ray (Raja clavata) from the Azores: Improving Scientific Information for the Effectiveness of Species-Specific Management Measures

First report of an egg nursery for the Critically Endangered flapper skate Dipturus intermedius (Rajiformes: Rajidae)

Life-history traits of batoids (Superorder Batoidea) in the Northeast Atlantic and the Mediterranean

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