SUMMARY: The feeding ecology of eight demersal elasmobranchs, three sharks (Etmopterus spinax, Scyliorhinus canicula and Galeus melastomus) and five batoids (Myliobatis aquila, Leucoraja naevus, Raja polystigma, R. miraletus and R. clavata), from the Balearic Sea (western Mediterranean) was analyzed. For each species, the diet and feeding habits were characterized by depth strata using quantitative indices such as diet overlap, diet breadth and prey diversity. Diet variation with size and depth were also tested for the most abundant species. For shelf-living species, natantian and reptantian crustaceans together with teleosts were the most important preys. On slope bottoms, euphausiids were the preferential prey for S. canicula and G. melastomus, while E. spinax fed mainly on cephalopods. The most specialist and generalist diet corresponded to G. melastomus living on the upper slope and S. canicula from the continental shelf, respectively. High overlap was found between all the skates on the continental shelf and the sympatric sharks S. canicula and G. melastomus on the slope. Significant overlap was also found between S. canicula and R. clavata on the continental shelf. Size was found to significantly affect the diet of S. canicula, G. melastomus and R. clavata, whereas depth affected exclusively S. canicula.Keywords: Elasmobranch, batoid, shark, feeding habits, diet overlap, niche breadth, Mediterranean. RESUMEN: Ecología alimentaria de elasmobranquios demersales de plataforma y talud en aguas de las Islas Baleares (Mediterráneo Occidental). -Se estudia la ecología alimentaria de ocho elasmobranquios demersales, tres tiburones (Etmopterus spinax, Scyliorhinus canicula y Galeus melastomus) y cinco rayas (Myliobatis aquila, Leucoraja naevus, Raja polystigma, R. miraletus y R. clavata), del mar Balear (Mediterráneo Occidental). Para cada especie se caracterizó la dieta y la estrategia alimentaria por estratos de profundidad mediante diferentes índices cuantitativos. También se analizó la variación intraespecífica de la dieta con la talla y la profundidad en las especies más abundantes. Las presas más frecuentes en especies de la plataforma continental fueron los peces y los crustáceos natantia y reptantia. En aguas del talud las presas principales de S. canicula y G. melastomus fueron los eufausiáceos, mientras que E. spinax consumió preferentemente cefalópodos. Las especies con la dieta más especializada y más generalista fueron G. melastomus del talud superior y S. canicula de la plataforma costera, respectivamente. En aguas de la plataforma se detectó solapamiento de dieta entre todas las especies de batoideos, así como entre S. canicula y R. clavata; el solapamiento fue significativo también entre S. canicula y G. melastomus del talud. Se observaron cambios ontogénicos en la dieta de S. canicula, G. melastomus y R. clavata, mientras que la única especie que mostró cambios de dieta con la profundidad fue S. canicula.Palabras clave: elasmobranquio, batoideo, tiburón, estrategia alimentaria, solapamiento de die...
This study reported on the circulation of a novel HMPV with a 180-nucleotide duplication in the G gene, but no clinical changes in related cases were observed. Their prevalence increased during the last season suggesting changes in viral features.
The Mediterranean Sea is one of the main hotspots of marine biodiversity in the world. The combined pressures of fishing activity and climate change have also made it a hotspot of global change amidst increasing concern about the worsening status of exploited marine species. To anticipate the impacts of global changes in the Mediterranean Sea, more integrated modelling approaches are needed, which can then help policymakers prioritize management actions and formulate strategies to mitigate impacts and adapt to changes. The aim of this study was to develop a holistic model of marine biodiversity in the Mediterranean Sea with an explicit representation of the spatial, multispecies dynamics of exploited resources subject to the combined influence of climate variability and fishing pressure. To this end, we used the individual-based OSMOSE model (Object-oriented Simulator of Marine ecOSystEms), including 100 marine species (fish, cephalopods and crustaceans) representing about 95% of the total declared catch, at a high spatial resolution (400 km2) and a large spatial scale (the entire Mediterranean basin)the first time such a resolution and scale have been modelled. We then combined OSMOSE with the NEMOMED 12 physical model and the Eco3M-S biogeochemical low trophic level model to build the endto-end model, OSMOSE-MED. We fitted OSMOSE-MED model with observed or estimated biomass and commercial catch data using a likelihood approach and an evolutionary optimization algorithm. The outputs of OSMOSE-MED were then verified against observed biomass and catch data, and compared with independent datasets (MEDITS data, diet composition and trophic levels). The model resultsat different hierarchical levels, from individuals to the scale of the ecosystemwere consistent with current knowledge of the structure, functioning and dynamics of the ecosystems in the Mediterranean Sea. While the model could be further improved in future iterations, all the modelling stepsthe comprehensive representation of key ecological processes and feedback, the selective parameterization of the model, and the comparison with observed data in the validation processstrengthened the predictive performance of OSMOSE-MED and thus its relevance as an impact model to explore the future of marine biodiversity under scenarios of global change. It is a promising tool to support ecosystem-based fishery management in the Mediterranean Sea. Highlights ► An End-to-End model (OSMOSE-MED) was built at the whole Mediterranean scale. ► One hundred marine species, representing 95 % of total declared catches, were embedded. ► OSMOSE-MED was fitted to observed and estimated data of biomass and catch. ► Results were consistent with current knowledge and observations on the system. ► The model can be used in support to fisheries management and biodiversity conservation.
SUMMARY:We assessed the elasmobranch communities exploited by the bottom trawl fishery off the Balearic Islands (northwestern Mediterranean) by analysing two time series containing information with different levels of detail: 1) a longterm series containing the abundance indices of the whole elasmobranch community landed from 1965 to 2009; and 2) a shorter time series from 2000 to 2009 from two different data sources (daily sales records: 2000-2009; bottom trawl surveys: 2001-2009), with information that allowed the shelf and slope to be analysed separately and different community parameters and abundance indices to be studied. Temporal trends of all these variables were used as ecological status indicators and tested with generalized additive models and analysis of variance. They were finally summarised using the Traffic Light methodology. The long-term series showed two marked trends, an inter-annual decreasing trend that would be a consequence of the large increase in fishing effort, and an intra-annual trend with a clear peak in May in accordance with the seasonal biological cycle of these species. However, data from the last ten years revealed differences between the shelf and slope, as some parameters increased significantly over time on the shelf but did not follow any trend on the slope. The Traffic Light methodology captured these differences well, demonstrating its usefulness for interpreting ecological transitions at a glance.Keywords: elasmobranchs, assessment, Traffic Light method, indicators, fishing effort, Balearic Islands. RESUMEN:Tendencias inter e intra-anuales e indicadores del estado de las poblaciones de elasmobranquios nectobentónicos de las Islas Baleares (Mediterráneo nordoccidental). -Se han evaluado las poblaciones de elasmobranquios explotadas por la pesca de arrastre de las Islas Baleares (Mediterráneo noroccidental) analizando dos series temporales con información a distinto nivel de detalle: 1) una serie larga que contiene únicamente el índice de abundancia de toda la población de elasmobranquios desembarcada entre 1965 y 2009 y 2) una serie corta a lo largo de la primera década del siglo XXI proveniente de dos fuentes de datos diferentes (hojas de venta diarias: 2000-2009; campañas de arrastre de fondo: 2001-2009), que permitieron el análisis, para la plataforma y el talud por separado, de diferentes parámetros de la comunidad además de índices de abundancia. Las tendencias temporales de todas estas variables se usaron como indicadores ecológicos de estado y se testaron aplicando modelos generales aditivos y análisis de la varianza y finalmente se han resumido usando la metodología de los Semáforos. La serie larga mostró dos señales claras, un decrecimiento interanual que podría ser consecuencia del importante incremento del esfuerzo pesquero, y una tendencia intra-anual con un claro pico en mayo, relacionado con el ciclo biológico estacional de estas especies. Así y todo, los datos del primer decenio del siglo XXI revelaron diferencias entre la plataforma y el talud, porque algu...
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