2 research outputs found
First record of Taningia danae (Cephalopoda: Octopoteuthidae) in the Mediterranean Sea
The capture of a specimen of the oceanic cephalopod Taningia danae Joubin, 1931, caught during a bottom trawl survey carried out off the Algerian coast, is reported for the first time in the Mediterranean Sea. The individual, which was taken at 385-395 m depth, was a juvenile with a 55.6 mm mantle length and age of 132 days. This finding is important as there are few worldwide records of this speciesPublicado
Large-scale spatio-temporal monitoring highlights hotspots of demersal fish diversity in the Mediterranean Sea
Increasing human pressures and global environmental change may severely affect the diversity of species
assemblages and associated ecosystem services. Despite the recent interest in phylogenetic and functional
diversity, our knowledge on large spatio-temporal patterns of demersal fish diversity sampled
by trawling remains still incomplete, notably in the Mediterranean Sea, one of the most threatened marine
regions of the world. We investigated large spatio-temporal diversity patterns by analysing a dataset
of 19,886 hauls from 10 to 800 m depth performed annually during the last two decades by standardised
scientific bottom trawl field surveys across the Mediterranean Sea, within the MEDITS program. A multicomponent
(eight diversity indices) and multi-scale (local assemblages, biogeographic regions to basins)
approach indicates that only the two most traditional components (species richness and evenness) were
sufficient to reflect patterns in taxonomic, phylogenetic or functional richness and divergence. We also
put into question the use of widely computed indices that allow comparing directly taxonomic, phylogenetic
and functional diversity within a unique mathematical framework. In addition, demersal fish assemblages sampled by trawl do not follow a continuous decreasing longitudinal/latitudinal diversity
gradients (spatial effects explained up to 70.6% of deviance in regression tree and generalised linear models),
for any of the indices and spatial scales analysed. Indeed, at both local and regional scales species
richness was relatively high in the Iberian region, Malta, the Eastern Ionian and Aegean seas, meanwhile
the Adriatic Sea and Cyprus showed a relatively low level. In contrast, evenness as well as taxonomic,
phylogenetic and functional divergences did not show regional hotspots. All studied diversity components
remained stable over the last two decades. Overall, our results highlight the need to use complementary
diversity indices through different spatial scales when developing conservation strategies and
defining delimitations for protected areas.VersiĂłn del editor3,269