Genetic diversity and gene flow of the threatened Brazilian endemic parrotfish Scarus trispinosus (Valenciennes, 1840).

The greenback parrotfish, Scarus trispinosus, is the largest herbivorous fish inhabiting Southwestern Atlantic reefs, and was recently included in the IUCN red list of threatened species as endangered due to the overexploitation of their populations. The aim of this work was to evaluate the existence of structured populations (i.e. genetic unities) along a coast of approximately 2000 km of the NE Brazilian coast. The transferability of 17 primers synthesized for Scarus rubroviolaceus was tested for S. trispinosus and five transferable loci were validated and used. Two localities within the Abrolhos Bank, off the Central Brazilian coast (Corumbau and Caravelas) and in close proximity to the MPA, which encompasses the largest remnants of the S. trispinosus population, exhibited higher levels of genetic richness. Remaining locations, Pernambuco, Porto Seguro and Rio Grande do Norte exhibited lower genetic diversity. We found no genetic differences among sampled localities however, when those samples were gathered into latitudinal groups (northern vs southern) a subtle but significant genetic substructuring was revealed. It is proposed that a combination of high local individual admixture favoured by habitat connectivity drived genetic homogeneity at regional scales while larval dispersal contributed to heterogeneities observed at large scales maintaining gene flow through oceanographic currents.

Genetic and oceanographic tools reveal high population connectivity and diversity in the endangered pen shell Pinna nobilis.

For marine meta-populations with source-sink dynamics knowledge about genetic connectivity is important to conserve biodiversity and design marine protected areas (MPAs). We evaluate connectivity of a Mediterranean sessile species, Pinna nobilis. To address a large geographical scale, partial sequences of cytochrome oxidase I (COI, 590 bp) were used to evaluate phylogeographical patterns in the Western Mediterranean, and in the whole basin using overlapping sequences from the literature (243 bp). Additionally, we combined (1) larval trajectories based on oceanographic currents and early life-history traits and (2) 10 highly polymorphic microsatellite loci collected in the Western Mediterranean. COI results provided evidence for high diversity and low inter-population differentiation. Microsatellite genotypes showed increasing genetic differentiation with oceanographic transport time (isolation by oceanographic distance (IBD) set by marine currents). Genetic differentiation was detected between Banyuls and Murcia and between Murcia and Mallorca. However, no genetic break was detected between the Balearic populations and the mainland. Migration rates together with numerical Lagrangian simulations showed that (i) the Ebro Delta is a larval source for the Balearic populations (ii) Alicante is a sink population, accumulating allelic diversity from nearby populations. The inferred connectivity can be applied in the development of MPA networks in the Western Mediterranean.

A first glance into the nutritional properties of the sea cucumber Parastichopus regalis from the Mediterranean Sea (SE Spain).

This work reports for the first time the nutritional profile, including proximate chemical composition, amino acids, fatty acids and minerals of Parastichopus regalis from the Mediterranean Sea (SE Spain). The studied species had a high moisture content, moderate protein and low lipid levels. The most abundant amino acids were glutamic acid, arginine and tyrosine. Polyunsaturated fatty acids, especially arachidonic acid, dominated the fatty acid profile. Iron, sodium, calcium and zinc were the most abundant mine rals. In general, P. regalis has a balanced nutritional quality suitable for human consumption.

First report of the nutritional profile and antioxidant potential of Holothuria arguinensis, a new resource for aquaculture in Europe.

This work reports for the first time the nutritional profile and antioxidant potential of the edible sea cucumber Holothuria arguinensis from the North-eastern Atlantic. H. arguinensis has high levels of protein, with the amino acids profile dominated by alanine, glycine and proline and low lysine/arginine ratios. Its carbohydrate and energetic contents are also low as well as the total lipid levels, although its lipid profile is rich in polyunsaturated fatty acids (PUFA), especially arachidonic, eicosapentaenoic and docosahexaenoic acids. In addition, H. arguinensis has high levels of calcium. The water and ethanol extracts show ability to scavenge free radicals and to chelate copper and iron ions. Our results indicate that H. arguinensis has a balanced nutritional quality suitable for human consumption. In addition, it contains compounds with antioxidant potential; thus its intake can contribute for a healthy and well-balanced diet.

Genetic evidence for polygynandry in the black-striped pipefish Syngnathus abaster: a microsatellite-based parentage analysis.

Sexual selection theory predicts that, in organisms with reversed sex roles, more polyandrous species exhibit higher levels of sexual dimorphism. In the family Syngnathidae (pipefish, seahorses, and seadragons), males provide all parental care by carrying developing embryos on their ventral surfaces, and females develop secondary sex characters. Syngnathids exhibit a variety of genetic mating patterns, making them an ideal group to test predictions of sexual selection theory. Here, we describe the mating system of the black-striped pipefish Syngnathus abaster, using 4 highly variable microsatellites to analyze parentage of 102 embryos. Results revealed that 1) both sexes mate multiple times over the course of a pregnancy (polygynandrous mating system), 2) eggs are spatially segregated by maternity within each brood pouch, and 3) larger females have higher mating success (Kolmogorov-Smirnov test; P < 0.05). Together with similar studies of other syngnathid species, our results support the hypothesis that the mating system is related to the intensity of sexual dimorphism.

Molecular systematics of the genus Holothuria in the Mediterranean and Northeastern Atlantic and a molecular clock for the diversification of the Holothuriidae (Echinodermata: Holothuroidea).

This work investigates the systematics of the genus Holothuria in the Mediterranean Sea and Northeastern Atlantic in the light of a wider molecular phylogenetic hypothesis of Holothuriidae, and it also provides a time-scale for the family diversification using mitochondrial markers and the molecular clock hypothesis. The subgenera Holothuria and Roweothuria are retrieved as paraphyletic. At least four separate lineages, with quite different time frameworks were identified. There are at least three species with an apparent long evolutionary history, H. forskali, H. sanctori and H. impatiens and six species belonging to Holothuria, Roweothuria and Vaneyothuria, which have diverged relatively recently.

Genetic diversity and connectivity remain high in Holothuria polii (Delle Chiaje 1823) across a coastal lagoon-open sea environmental gradient.

Coastal lagoons represent habitats with widely heterogeneous environmental conditions, particularly as regards salinity and temperature, which fluctuate in both space and time. These characteristics suggest that physical and ecological factors could contribute to the genetic divergence among populations occurring in coastal lagoon and open-coast environments. This study investigates the genetic structure of Holothuria polii at a micro-geographic scale across the Mar Menor coastal lagoon and nearby marine areas, estimating the mitochondrial DNA variation in two gene fragments, cytochrome oxidase I (COI) and 16S rRNA (16S). Dataset of mitochondrial sequences was also used to test the influence of environmental differences between coastal lagoon and marine waters on population genetic structure. All sampled locations exhibited high levels of haplotype diversity and low values of nucleotide diversity. Both genes showed contrasting signals of genetic differentiation (non-significant differences using COI and slight differences using 16S, which could due to different mutation rates or to differential number of exclusive haplotypes. We detected an excess of recent mutations and exclusive haplotypes, which can be generated as a result of population growth. However, selective processes can be also acting on the gene markers used; highly significant generalized additive models have been obtained considering genetic data from 16S gene and independent variables such as temperature and salinity.

A mitochondrial DNA based phylogeny of weakfish species of the Cynoscion group (Pisces: Sciaenidae).

We infer the phylogeny of fishes in the New World Cynoscion group (Cynoscion, Isopisthus, Macrodon, Atractoscion, Plagioscion) using 1603bp of DNA sequence data from three mitochondrial genes. With the exception of Plagioscion, whose position was ambiguous, the Cynoscion group is monophyletic. However, several genera examined are not monophyletic. Atlantic and Pacific species of Cynoscion are interspersed in the tree and geminate species pairs are identified. Intergeneric relationships in the group are clarified. Our analysis is the first comprehensive phylogeny for the Cynoscion group based on molecular data and provides a baseline for future comparative studies of this important group.