Data on the diet of species are important for understanding ecosystem dynamics and are fundamental for the implementation of recent approaches in stock assessment and consequently for the establishment of more ecological management measures. In mainland Portugal, as in most European countries, skates and rays represent an important proportion of commercial landings. The four main species landed are Raja clavata and Raja brachyura, followed by Leucoraja naevus and Raja montagui. This paper analyses their diets based on the examination of stomach contents. Food items were identified to the lowest identifiable taxon and were further assembled into major taxonomic groups designated as prey. Intra- and interspecific comparisons were made according to size and sex. All four species had generalized diets with differences in prey preference among them. Decapods and bony fish were the most frequent prey. Furthermore, an ontogenetic dietary shift was evident in all species at around 45−55 cm total length. Both intra- and interspecific differences observed seem to be related to size and morphological characteristics of the species, as well as type of dentition. These variations allow different species, as well as small and large specimens from the same species, to exploit a larger diversity of habitats. Les données sur le régime alimentaire sont importantes pour comprendre la dynamique des écosystèmes, et sont fondamentales pour mettre en œuvre les approches récentes de gestion des stocks, et donc pour établir des mesures de gestion plus écologiques. Au Portugal, comme dans les autres pays européens, les raies représentent un part importante des débarquements commerciaux. Les quatre espèces principales débarquées sont Raja clavata et Raja brachyura, suivies de Leucoraja naevus et Raja montagui. Cet article analyse leur régime alimentaire en se basant sur les contenus stomacaux. Leurs aliments sont identifiés au taxon le plus précis possible, puis regroupés par groupes taxonomiques désignés comme proies. Les comparaisons intra- et interspécifiques des raies sont faites selon leur taille et leur sexe. Les quatre espèces présentent des différences dans leur préférence alimentaire. Les Décapodes et les poissons osseux sont les proies les plus fréquentes. De plus, un changement ontogénique est évident au niveau alimentaire, et pour les quatre espèces, autour de 45−55 cm (longueur totale). Les différences intra- et interspécifiques observées semblent liées à la taille et aux caractéristiques morphologiques de l'espèce, ainsi qu'à la dentition. Ces variations leur permettent quelle soit la taille d'exploiter une plus grande diversité d'habitats.

Two genera of elasmobranchii, Centrophorus and Centroscymnus, include species that represent the highest landings of deep-water sharks caught by fishing fleets operating in the north-east Atlantic. There are morphology-based identification problems among and within genera, and landings of processed shark products further prevent an objective assessment of these species. The present study is the first attempt to test the suitability of using a DNA barcode approach to discriminate accurately among the four most important commercial deep-water shark species: Centrophorus squamosus, Centrophorus granulosus, Centroscymnus coelolepis and, recently discovered in Portuguese ports, Centroscymnus owstoni. Sequence analyses of the mitochondrial DNA cytochrome c oxidase subunit I (COI) gene revealed low levels of haplotypic and genetic diversities. Higher levels of inter-specific relative to intra-specific divergences allowed discrimination among species, which form reciprocally monophyletic clades. Inclusion of published COI sequences from other species within the same genera revealed haplotype sharing among species, which calls into question the current taxonomy and accuracy of fisheries data available. Amplification of the COI gene coupled with MboI restriction digests was found to be a fast and inexpensive strategy to resolve within genera identification problems. Molecular barcoding constitutes a critical tool for the assessment and implementation of urgent management policies for this group of species.

Data on age and reproduction of the rabbitfish at the Portuguese continental slope are presented. Ages were estimated based on transverse sections of the dorsal spine. Differences in growth patterns were detected between sexes—males grow slower and are smaller than females. The results from histological analysis of different development stages of testes indicated that the macroscopic scale used is well adapted to rabbitfish sampled in Portuguese waters. In females and excluding macroscopic Stage 4, which according to the adopted scale corresponds to an active phase, all the remaining stages were identified in the samples. Ovarian fecundity was estimated as 6·46±2·32 oocytes (females range: 45·0 to 70·0 cm pre-supra caudal fin length [PSCFL]). Length of first maturity in males (40·7 cm PSCFL) is lower than in females (45·9 cm PSCFL).