First record of the twobar sea bream Acanthopagrus bifasciatus (Teleostei: Sparidae) in the Mediterranean Sea

In September 2010, one specimen of the twobar seabream Acanthopagrus bifasciatus was recorded for the first time in the Mediterranean Sea, off the Islands of Zembra (Gulf of Tunisi: 37°07’03’’N; 10°48’35’’E). This species could have entered the Mediterranean via the Suez Canal or alternatively by unintentional human transport

Contrasting Responses to Harvesting and Environmental Drivers of Fast and Slow Life History Species

According to their main life history traits, organisms can be arranged in a continuum from fast (species with small body size, short lifespan and high fecundity) to slow (species with opposite characteristics). Life history determines the responses of organisms to natural and anthropogenic factors, as slow species are expected to be more sensitive than fast species to perturbations. Owing to their contrasting traits, cephalopods and elasmobranchs are typical examples of fast and slow strategies, respectively. We investigated the responses of these two contrasting strategies to fishing exploitation and environmental conditions (temperature, productivity and depth) using generalized additive models. Our results confirmed the foreseen contrasting responses of cephalopods and elasmobranchs to natural (environment) and anthropogenic (harvesting) influences. Even though a priori foreseen, we did expect neither the clear-cut differential responses between groups nor the homogeneous sensitivity to the same factors within the two taxonomic groups. Apart from depth, which affected both groups equally, cephalopods and elasmobranchs were exclusively affected by environmental conditions and fishing exploitation, respectively. Owing to its short, annual cycle, cephalopods do not have overlapping generations and consequently lack the buffering effects conferred by different age classes observed in multi-aged species such as elasmobranchs. We suggest that cephalopods are sensitive to short-term perturbations, such as seasonal environmental changes, because they lack this buffering effect but they are in turn not influenced by continuous, long-term moderate disturbances such as fishing because of its high population growth and turnover. The contrary would apply to elasmobranchs, whose multi-aged population structure would buffer the seasonal environmental effects, but they would display strong responses to uninterrupted harvesting due to its low population resilience. Besides providing empirical evidence to the theoretically predicted contrasting responses of cephalopods and elasmobranchs to disturbances, our results are useful for the sustainable exploitation of these resourcesVersión del editor4,411

Residencia y albergue en el Camino de Santiago [Hojas Resumen]

Residencia y albergue en el Camino de santiag

Residencia y albergue en el Camino de Santiago [Hojas Resumen]

Residencia y albergue en el Camino de santiag

Distribution of blackchin guitarfish Rhinobatos cemiculus E. Geoffroy Saint-Hilaire, 1817 (Elasmobranchii: Rhinobatidae) with first records from (I) over dot zmir Bay (Turkey, northeastern Aegean Sea)

WOS: 000336620300008Blackchin guitarfish, Rhinobatos cemiculus, is rather abundantly captured in the eastern tropical Atlantic, especially off Senegal and Mauritania. In the Mediterranean western basin, R. cemiculus is unknown at present off the European shore but is rather frequent off southern areas; conversely, the species occurs throughout the eastern basin. Two large specimens recorded for the first time in (I) over dot zmir Bay, northern Aegean Sea, are reported and described in this note. These findings constitute the northernmost records of R. cemiculus in both the Aegean Sea and the Mediterranean Sea, and they significantly extend the species' distribution known to date