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The potential bioaccumulation of pollutants, such as heavy metals, may pose a threat to the western Mediterranean chondrichthyans and human consumers. Therefore, the first extensive assessment of cadmium (Cd), lead (Pb), and copper (Cu) concentrations in the muscle tissue of 17 species of sharks, rays, and chimaeras in this region was conducted via Microwave Assisted Extraction (MAE) and Graphite Furnace Atomic Absorption Spectrometry (GFAAS). Significant differences between species were observed, particularly related to the rabbit fish (Chimaera monstrosa) and the velvet belly lantern shark (Etmopterus spinax), which exceeded the European Union (EU) Commission Regulation 2023/915 threshold of Cd. Overall, heavy metal concentrations correlated negatively with size and trophic level but positively with depth. Although the consumption of these species may entail minimal risk to adult humans, caution is advised, especially for children. These findings are important due to the widespread consumption of chondrichthyans in many western Mediterranean regions

Parlem amb Claudio Flavio i Annabel Colmenero, de l'associació Catshark, dedicada a la protecció de taurons i rajades, dues de les espècies marines més amenaçades del món i la Mar Mediterrània no n'és cap excepció. La sobrepesca, la pesca accidental i la contaminació són les principals amenaces d'aquestes espècies, que veuen reforçades les seves aspiracions de supervivència i benestar amb l'arribada de Catshark, l'activitat de la qual és clau en la defensa dels ecosistemes marins tal i com exposen els seus representants a Arran De Mar

The seafloor of the Mediterranean Sea accumulates marine litter (ML), an area where bottom trawlers operate and can accidentally catch the litter from the seafloor. This study aims to describe and quantify the ML caught by bottom trawlers along the Catalan coast (NW Mediterranean Sea) and estimate the potential of the bottom trawl fleet to extract ML from the area as a Fishing for Litter (FFL) initiative to tackle the ML issue. Marine litter was collected from commercial trawlers and was classified as metal, plastic, rubber, textile, wood, and other waste and weighed (kg) from 305 hauls performed during three years (2019–2021) from 9 different ports at 3 different depths. ML was present in 97 % of the hauls, with plastic being the most abundant material. The composition varied according to zone, port and depth, with the highest densities found in highly urbanized areas (13.75 ± 3.25 kg km−2), which mainly contained plastics (74.3 %). The port of Barcelona had the highest presence of plastics (23.62 ± 6.49 kg km−2), mainly wet wipes. Regarding depth, the continental shelf had the highest density of ML, with 12.24 ± 2.40 kg km−2. The potential ML removal (t year−1) was calculated using fishing effort (hours). It is estimated that the bottom trawlers may potentially remove 237 ± 36 t year−1 of ML in the Catalan coast. FFL initiatives should be part of a multidisciplinary approach to tackle marine litter, which must include prevention, monitoring, and cleaning actions

On 15 March 2021, a male Hexanchus griseus was incidentally captured by a commercial bottom trawler at 550-730 m depth in the Gulf of Valencia (Spain). The specimen measured 251.8 cm in total length, weighed 86.2 kg and its reproductive system was fully developed, characterizing it as the smallest mature male bluntnose sixgill shark recorded in the Mediterranean Sea. The specimen hosted the ectoparasitic copepod Demoleus heptapus. Remains of a Stenella coeruleoalba calf were identified in its stomach content by applying molecular methods. The feeding behaviour of H. griseus as either actively preying on live cetaceans or as scavenging on carcasses is reviewed and discussed to better understand the species’ role in marine food webs

Introduction: Chondrichthyans (sharks, batoids and chimaeras) play key roles in the regulation of marine food webs dynamics. However, more than half of the assessed species in the Mediterranean are threatened, primarily by fishing pressure and compounded by habitat degradation and climate change. Nevertheless, there is an important knowledge gap in identifying the underlying drivers of their community structure and spatial distribution. Methods and Results: We provide insights into the current bycatch rates of chondrichthyans in the western Mediterranean commercial bottom trawling fishery by accurately depicting the unaltered practices of the local fleet. A total of 17 species were recorded in the studied fishing grounds (ranging from 50 to 800 m deep), including 7 sharks, 9 batoids, and 1 chimaera, although the total catch was dominated by few species. Furthermore, we tested the effect of environmental and fishing-related factors on multiple community descriptors by using analysis of community structure (multidimensional scaling and analysis of similitude) and generalized linear mixed models to further understand the drivers of the chondrichthyan community distribution and structure. This study revealed the importance of combining environmental and anthropogenic drivers to further understand the spatial distribution patterns of chondrichthyan communities. Our results indicate that depth was the main driver of the community structure, with deeper areas within the fishing grounds hosting a higher diversity. Sea bottom temperature and substrate type also influenced the distribution of the community, with substrate effects changing depending on the intensity of fishing pressure. In all cases, density, biomass, and diversity of chondrichthyans were negatively impacted by increasing fishing effort. Discussion: Understanding the drivers of the structure and distribution of the chondrichthyan community is crucial to understand the potential impacts that increased fishing p

The Mediterranean Sea has registered great abundances of benthic marine litter (ML). The seafloor is often where it accumulates, an area shared with the activity of bottom trawlers, which can accidentally catch the litter from the seafloor, in strategies named Fishing for Litter (FFL). Thus, this study describes, quantifies and maps the ML caught by bottom trawlers along the Catalan coast (NW Mediterranean Sea). The litter was obtained from 305 hauls performed during three years (2019-2021) from 9 different ports at 3 depth strata covering from 20 to 700 m. In the laboratory, the ML was weighted and classified in six different categories (metal, plastic, rubber, textile, wood, and other waste). ML was present in 97 % of the hauls, which composition varied according to zone, port and depth, with the highest densities found in highly urbanized areas (13.75 ± 3.25 kg km-2), which mainly contained plastics (74,3 %). The port of Barcelona had the highest presence of plastics (23.62 ± 6.49 kg km-2), mainly wet wipes. Regarding depth, the continental shelf had the highest density of ML, with 12.24 ± 2.40 kg km-2. The effect of different ML sources was tested in order to evaluate spatial distribution of ML in the Catalan seafloor. To conclude, the bottom trawl fleet of the Catalan coast has the potential to remove 237 ± 36 t of marine litter yearly. Therefore, FFL initiatives should be part of a multidisciplinary approach to tackle marine litter, which must include prevention, monitoring, and cleaning actions

The intricate balance of marine ecosystems relies heavily on the presence of apex predators, and among them, elasmobranchs stand out as formidable top predators. These enigmatic creatures play a pivotal role in maintaining the health and equilibrium of marine environments (Myers et al., 2007). However, despite their ecological significance, elasmobranch populations are experiencing a concerning global decline, primarily attributed to the intersection of anthropogenic disturbances and shifting environmental conditions. A particular impact is due do different fishing activities, not only the “industrial” ones, but also artisanal fisheries was demonstrated to negatively affect elasmobranchs populations (Tiralongo et al., 2018; Mancusi et al., 2020). At the forefront of these threats is the pervasive impact of fishing activities, posing a substantial challenge to the conservation of elasmobranchs worldwide. Overfishing, coupled with unintended interactions in non-targeted fisheries, has emerged as a significant driver behind the diminishing populations of these iconic marine species. The repercussions of these trends are further exacerbated by the escalating demands on global fisheries and the concurrent depletion of fish stocks, foreshadowing an ominous trajectory for elasmobranchs in the decades to come (Pacuoreau et al., 2021). [...]

The situation for chondrichthyans in the Mediterranean Sea is particularly concerning, with 53% of the assessed species classified as threatened (IUCN). Chondrichthyans constitute an important percentage of the catch for multi-specific fisheries, particularly for bottom trawling, but a minor part of landings. Monitoring programs are essential to assess the status of chondrichthyan communities. Our research provides updated information on the structure and status of the demersal chondrichthyan assemblage inhabiting trawling fishing grounds from the northern Spanish Mediterranean (GFCM GSA06). Data was obtained from 187 hauls conducted by commercial bottom trawlers on a seasonal basis between June 2020 and January 2022 as part of the projects ECEME and SAP-ICATMAR. Surveys ranged from 50 to 800 m deep. A total of 17 chondrichthyan species belonging to 12 families occurred throughout the area, shaping two different assemblages in relation to depth. Richness increased with depth and decreased with latitude, but the most common species all along the area were Scyliorhinus canicula, Galeus melastomus, Etmopterus spinax and Torpedo marmorata, accounting for the largest proportion of total density and biomass. We mapped the geographical, bathymetrical, and seasonal distribution patterns in relation to sex and maturity stage for the most common species. Thus, we shed light into their sexual and ontogenetic segregation patterns and unravel important aspects of their ecology. The aim of this work was to improve the required knowledge to assess the status and susceptibility of the chondrichthyan populations inhabiting the western Mediterranean Sea, aiding to a more efficient management of the associated fisheries

Desde Observadores del Mar del CSIC y la RedPROMAR del Gobierno de Canarias, ambas plataformas de ciencia ciudadana marina, hemos establecido una alianza para seguir impulsando, de manera colaborativa, la ciencia ciudadana marina para el seguimiento, vigilancia, conocimiento y conservación de la biodiversidad marina. El pasado 7 y 8 de noviembre tuvo lugar el evento para dar a conocer esta colaboración y establecer el marco de trabajo colaborativo estatal. El encuentro reunió a representantes de administraciones públicas estatales, autonómicas y municipales, centros de investigación de todo el territorio, entidades y ciudadanía. El objetivo común: hacer que la ciencia ciudadana sea útil para la conservación marina

Among the main measures adopted to reduce anthropogenic impacts on elasmobranch communities, understanding the ecology of deep-sea sharks is of paramount importance, especially for potentially vulnerable species highly represented in the bycatch composition of commercial fisheries such as the blackmouth catshark Galeus melastomus. In the present work, we unravelled the first indication of population genetic structure of G. melastomus by using a novel and effective panel of nuclear, and polymorphic DNA markers and compared our results with previous findings supporting high genetic connectivity at large spatial scales. Given the lack of species-specific nuclear markers, a total of 129 microsatellite loci (Simple Sequence Repeats, SSRs) were cross-amplified on blackmouth catshark specimens collected in eight geographically distant areas in the Mediterranean Sea and North-eastern Atlantic Ocean. A total of 13 SSRs were finally selected for genotyping, based on which the species exhibited signs of weak, but tangible genetic structure. The clearcut evidence of genetic differentiation of G. melastomus from Scottish waters from the rest of the population samples was defined, indicating that the species is genetically structured in the Mediterranean Sea and adjacent North-eastern Atlantic. Both individual and frequency-based analyses identified a genetic unit formed by the individuals collected in the Tyrrhenian Sea and the Strait of Sicily, distinguished from the rest of the Mediterranean and Portuguese samples. In addition, Bayesian analyses resolved a certain degree of separation of the easternmost Aegean sample and the admixed nature of the other Mediterranean and the Portuguese samples. Here, our results supported the hypothesis that the interaction between the ecology and biology of the species and abiotic drivers such as water circulations, temperature and bathymetry may affect the dispersion of G. melastomus, adding new information to the current knowledge of the con

En este episodio hablamos del #Reto Tiburones y rayas con Claudio Barría, responsable del proyecto en Observadores del Mar y director y cofundador de Catsharks; Biel Morey (miembro del grupo de especialistas de Tiburones en la UICN y cofundador de Save The Med; Debora Morrison, directora de conservación de la Fundación Palma Aquarium; y Sandra Espeja, coordinadora de Observadores del Mar en Baleares

The current shift of fishery efforts towards the deep sea is raising concern about the vulnerability of deep-water sharks, which are often poorly studied and characterized by problematic taxonomy. For instance, in the Mediterranean Sea the taxonomy of genus Centrophorus has not been clearly unravelled yet. Since proper identification of the species is fundamental for their correct assessment and management, this study aims at clarifying the taxonomy of this genus in the Mediterranean Basin through an integrated taxonomic approach. We analysed a total of 281 gulper sharks (Centrophorus spp.) collected from various Mediterranean, Atlantic and Indian Ocean waters. Molecular data obtained from cytochrome c oxidase subunit I (COI), 16S ribosomal RNA (16S), NADH dehydrogenase subunit 2 (ND2) and a portion of a nuclear 28S ribosomal DNA gene region (28S) have highlighted the presence of a unique mitochondrial clade in the Mediterranean Sea. The morphometric results confirmed these findings, supporting the presence of a unique and distinct morphological group comprising all Mediterranean individuals. The data strongly indicate the occurrence of a single Centrophorus species in the Mediterranean, ascribable to C. cf. uyato, and suggest the need for a revision of the systematics of the genus in the area

La mitad de los ejemplares de tintorera captados con cámaras trampa en Baleares vive con un anzuelo clavado

The occurrence of the rendezvous fish, Polymetme corythaeola (Alcock, 1898) in Mediterranean Sea is here reported for the first time. A single individual of this benthopelagic fish was caught in February 2020 during a scientific trawl survey. The specimen was collected at a depth of 369 m (upper slope) in the Gulf of Roses (Catalonia, north-western Mediterranean). This circumglobal species could have naturally expanded its distribution through the Strait of Gibraltar, but we cannot totally exclude that its Mediterranean occurrence has been overlooked thus far. This finding highlights the importance of continuous monitoring of Mediterranean deep-sea habitats for a better understanding of their diversity and ongoing transformation

[EN] The diamondback squid Thysanoteuthis rhombus Troschel, 1857 is a large and elusive oceanic squid spe-cies. Here, we provide the first record of the species for the Catalan coast and integrate this finding in the current knowledge of the species in close area, [ES] El chipirón volantín (Thysanoteuthis rhombus Troschel, 1857) es una especie de calamar oceánico grande y elusivo. En este trabajo se proporciona el primer registro de la especie para la costa catalana y se discute en el contexto de registros de la especie en zonas cercanas

The Mediterranean Sea has a long-lasting history of fishery exploitation that, together with other anthropogenic impacts, has led to declines in several marine organisms. In particular, elasmobranch populations have been severely impacted, with drastic decreases in abundance and species diversity. Based on their experience, fishers can provide information on marine species occurrence, abundance and behavioural traits on a long-term scale, therefore contributing to research on the poorly studied biological aspects of elusive or rare elasmobranch species. In this study, for the first time, the use of the Local Ecological Knowledge (LEK) of fishers was applied to study the behavioural traits of sharks, rays and skates in 12 FAO-GFCM geographical sub-areas (GSAs) of the Mediterranean Sea. This study found both new insight and proved the reliability of LEK-based catch seasonality, reflecting seasonal movements, by comparing LEK-based findings and available literature on five elasmobranch taxa (Mustelus spp., Squalus acanthias, Raja spp., Myliobatis aquila and Scyliorhinus stellaris) in the Adriatic Sea and 7 taxa (Mustelus spp., Raja spp., Prionace glauca, Scyliorhinus canicula, Torpedo spp., Pteroplatytrygon violacea and Isurus oxyrinchus) in the remaining Mediterranean GSAs. In addition, LEK provided new insights into a novel comprehensive representation of species aggregations (Mustelus spp., S. acanthias, M. aquila and S. canicula) in the sampled GSAs and supplied the first descriptions of the size, number of individuals and sex composition of the aggregations. When the limits and shortcomings of LEK-based research are considered, this methodology can be a complementary and cost-effective tool used to study elasmobranchs in either a data-poor scenario or a scenario in which a baseline is missing. LEK can also be useful for the evaluation and inclusion of fishers’ perceptions on bottom-up management and to provide important evidence for conservation plans

Trophic studies are key to understand the ecological role of marine species in natural ecosystems. In this study, we examined the trophic ecology of the holocephalan rabbitfish Chimaera monstrosa, a demersal chondrichthyan considered Near Threatened by the Mediterranean red list assessment of the IUCN. The study was based on the analysis of the stomach content of 86 individuals inhabiting deep-sea waters of the Gulf of Lions (northwestern Mediterranean Sea). Additionally, to the description of the diet and trophic position of this species, we compared its diet between sexes and maturity stages. The results revealed that the rabbitfish in this Mediterranean ecosystem is a mesopredator, specialized on the consumption of crustaceans and feeding almost exclusively on the decapod Monodaeus couchii, independently of sex or maturity stage. These results grant new information about the trophic ecology of this rarely studied species in the Mediterranean Sea

Sharks are among the oldest residents of the planet, they possess a unique value as top predators and constitute irreplaceable elements of marine ecosystems. Unfortunately, contemporary narratives widely presented in popular mainstream media have attached an utterly negative connotation to sharks, propagating an unsubstantiated and fabricated image of them as implacable and voracious predators. Recently a lot of attention is devoted to understanding the public perception towards sharks in order to promote their conservation given that a quarter of all shark species are facing extinction. This work assessed the current attitude of the public towards sharks on a global scale, utilizing modern technology through a single protocol that explored the importance of factors like culture, history, or educational level in shaping attitudes. We collected 13,800 questionnaires from 137 countries, with 25 countries presenting more than 100 answers each, representing in total 92% of the filled questionnaires. A generally positive attitude towards sharks emerged from our study, influenced significantly by several factors including knowledge and participation in marine conservation projects. Interestingly, shark attacks emerged as an important factor, with countries having high numbers of shark attacks exhibiting a highly positive attitude towards sharks, potentially because their citizens are more aware of the issue and the importance of sharks for the marine ecosystems. Guidelines for shifting public attitude towards sharks and consequently advancing shark conservation were also drawn

¿Quieres conocer cuáles son los principales riesgos para la megafauna en el Mediterráneo? El cambio climático, la contaminación marina y la pesca accidental son algunas de las amenazas a las que se enfrentan delfines, tortugas, tiburones y rayas. En este coloquio, celebrado con motivo del #DíaMundialDeLosOceáneos, investigadores del Instituto Cavanilles de Biodiversidad y Biología Evolutiva (ICBiBE) de la Universitat de València y el Institut de Ciències del Mar - CSIC repasan los principales peligros que ponen en riesgo la supervivencia de estos grupos zoológicos

This document presents the State of Fisheries in Catalonia between October 2019 and December 2020, both inclusive. It was produced by the Catalan Institute for Ocean Governance Research (ICATMAR), which is a cooperation organism between the Directorate-General of Maritime Policy & sustainable fisheries of the Government of Catalonia and the Institute of Marine Sciences (ICM) of the Spanish National Research Council (CSIC)