Mostrando recursos 1 - 20 de 1.019

  1. Contrasting movements and residency of two serranids in a small Macaronesian MPA

    Afonso, Pedro; Abecasis, David; Santos, Ricardo Serrão; Fontes, Jorge
    Protection inside marine reserves and the desired ‘reserve effect’ depend directly on the home rangeand sedentary behaviour of fishes throughout their lives. Benthic territorial predators are typically seenas major candidates to beneficiaries, but empirical evidence of short-versus long term residency is stillsurprisingly rare. We studied the inter-annual patterns of site fidelity and finer scale movements in twoof the most abundant benthic predators of the NE Atlantic coastal reefs, the dusky grouper (Epinephelusmarginatus) and the blacktail comber (Serranus atricauda), using passive acoustic telemetry inside andaround a small marine reserve in the Azores islands, central North Atlantic. Individuals of both speciesresided in...

  2. A well-kept treasure at depth: precious red coral rediscovered in Atlantic deep coral gardens (SW Portugal) after 300 years

    Boavida, Joana; Paulo, Diogo; Aurelle, Didier; Arnaud-Haond, Sophie; Marschal, Christian; Reed, John; Gonçalves, J. M. S.; Serrão, Ester
    The highly valuable red coral Corallium rubrum is listed in several Mediterranean Conventions for species protection and management since the 1980s. Yet, the lack of data about its Atlantic distribution has hindered its protection there. This culminated in the recent discovery of poaching activities harvesting tens of kg of coral per day from deep rocky reefs off SW Portugal. Red coral was irregularly exploited in Portugal between the 1200s and 1700s, until the fishery collapsed. Its occurrence has not been reported for the last 300 years.

  3. A new Euthria (Gastropoda: Buccinidae) from the Cape Verde Archipelago

    Fraussen, Koen; Afonso, Carlos M. L.
    A small, yet beautiful species collected at north to northwestern Sal Island (Cape Verde Archipelago), and hitherto consistently identified as E. calderoni Rolán, 1985, is recognised as distinct and is described as new: Euthria taeniopsoides sp. nov.

  4. Morphological analysis and description of the ovaries of female silky sharks, Carcharhinus falciformis (Müller & Henle, 1839)

    Rego, Mariana G.; Hazin, Fabio H. V.; Evencio Neto, Joaquim; Oliveira, P. G. V.; Soares, Maria Goretti; Torres, Keilla Regina L. S.; Lana, Fernanda O.; Roque, Pollyana C. G.; Santos, Natalia L.; Coelho, Rui
    This work aims to study the female reproductive tract of silky sharks, Carcharhinus falciformis, captured in the South and Equatorial Atlantic Ocean. Samples were collected between January 2008 and March 2010 through oceanic commercial vessels that targeted tuna and swordfish, with a total of 17 females collected. The methodologies followed for analyzing the ovaries of those females included both macroscopic and histological analysis. Macroscopically, it was possible to determine that the ovaries on these sharks is suspended by mesenteries in the anterior section of the body cavity, heavily irrigated by blood vessels, and contains a wide range of oocytes. Ovaries were found in three distinct...

  5. Use of encounter data to model spatio-temporal distribution patterns of endangered smalltooth sawfish, Pristis pectinata, in the western Atlantic

    Waters, John D.; Coelho, Rui; Fernandez-Carvalho, Joana; Timmers, Amy A.; Wiley, Tonya; Seitz, Jason C.; Mcdavitt, Matthew T.; Burgess, George H.; Poulakis, Gregg R.
    1. Sawfishes are among themost threatened fish species globally,with only the smalltooth sawfish (Pristis pectinata) currently regularly observed in the westernAtlantic. TheNational Sawfish EncounterDatabase (NSED) documents reported encounters with sawfishes in the western Atlantic and contains 4945 reports of 8773 individual P. pectinata (1782–2011). 2. Statistical modelling (generalized linear models and generalized additive models) and kernel density analyses were used to (1) identify spatio-temporal patterns among encounter reports, including range reduction in the western Atlantic; (2) determine current distribution to identify areas and time periods where conservation and recovery efforts could be focused; and (3) identify and describe spatio-temporal distribution patterns of large juveniles and adults. 3....

  6. Identification of weakfish Cynoscion (Gill) in the Bay of Panama with RFLP markers

    Vergara-Chen, Carlos; González-Wangüemert, Mercedes; Bermingham, Eldredge; D’Croz, L.
    A molecular approach, polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), was developed to identify the planktonic larvae of Cynoscion species. Species-specific mitochondrial DNA markers were developed using three restriction endonucleases (DdeI, HaeIII and HinfI). These markers permitted the accurate discrimination of the five Cynoscion species in the Bay of Panama.

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

    Vergara-Chen, Carlos; Aguirre, Windsor E.; González-Wangüemert, Mercedes; Bermingham, Eldredge
    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.

  8. High gene flow promotes the genetic homogeneity of the fish goby Pomatoschistus marmoratus (Risso, 1810) from Mar Menor coastal lagoon and adjacent marine waters (Spain)

    Vergara-Chen, Carlos; González-Wangüemert, Mercedes; Marcos, Concepción; Pérez-Ruzafa, Ángel
    The extreme environmental variability of coastal lagoons suggests that physical and ecological factors could contribute to the genetic divergence among populations occurring in lagoon and open-coast environments. In this study we analysed the genetic variability of lagoon and marine samples of the sand goby, Pomatoschistus marmoratus (Risso, 1810) (Pisces: Gobiidae), on the SW Spain coast. A fragment of mitochondrial DNA control region (570 bp) was sequenced for 196 individuals collected in five localities: Lo Pagan, Los Urrutias and Playa Honda (Mar Menor coastal lagoon), and Veneziola and Mazarro´n (Mediterranean Sea). The total haplotype diversity was h = 0.9424 ± 0.0229, and the total nucleotide diversity was p = 0.0108...

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

    Roggatz, Christina C.; González-Wangüemert, Mercedes; Pereira, Hugo; Rodrigues, Maria João; Silva, Manuela Moreira da; Barreira, Luísa; Varela, João; Custódio, Luísa
    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...

  10. A new record of Holothuria arguinensis colonizing the Mediterranean Sea

    González-Wangüemert, Mercedes; Borrero-Pérez, Giomar
    Holothuria arguinensis is reported for the first time on the south-eastern Spanish coast. One specimen of this species was identified in El Mojo´n (Alicante, Spain, 37850′54.17′′N 0845′39.90′′W). This finding widens the geographical range of H. arguinensis and demonstrates that its environmental requirements are changing. Future genetic studies in this species would allow us to improve our understanding of its colonization from the Atlantic Ocean to the Mediterranean Sea.

  11. Modelling spatial and temporal scales for spill-over and biomass exportation from MPAs and their potential for fisheries enhancement

    Pérez-Ruzafa, Ángel; Martín, Ernesto; Marcos, Concepción; Zamarro, José Miguel; Stobart, Ben; Harmelin-Vivien, Mireille; Polti, Sandrine; Planes, Serge; García-Charton, José Antonio; González-Wangüemert, Mercedes
    Marine protected areas (MPAs) are considered as a tool for marine conservation and sustainable fishery resource management. Improvements in fishery yields should take place via the spill-over of individuals from the reserve. In general, it has been demonstrated that MPAs affect the density and biomass of the organisms within them, however, little evidence has been found in order to assess the exportation of individuals across their boundaries. In this study, a simple model involving population growth, harvest, and the diffusion coefficient for individuals was used to explore the effects of protection on populations inside the reserve and the spill-over of...

  12. Effects of fishing protection on the genetic structure of fish populations

    Pérez-Ruzafa, Ángel; González-Wangüemert, Mercedes; Lenfant, Philippe; Marcos, Concepción; García-Charton, José Antonio
    Marine reserves have been identified as an important tool in the management of fishery resources and their number is increasing rapidly, most of them being on islands. However, knowledge on the real effect of protection from fishing on the genetic structure of populations, the spatial scales involved, or the suitability of islands as reserves in terms of connectivity, is scarce. This paper analyses the effects of fishery protection on the genetic structure of populations of Diplodus sargus, a target species, in protected and non-protected areas of the western Mediterranean. Populations studied showed high genetic variability at spatial scales from 101 to 103 km. Protected areas have significantly...

  13. Setting preliminary biometric baselines for new target sea cucumbers species of the NE Atlantic and Mediterranean fisheries

    González-Wangüemert, Mercedes; Valente, Sara; Henriques, Filipe; Domínguez-Godino, Jorge A.; Serrão, Ester A.
    Commercial interest on sea cucumber species from the NE Atlantic and the Mediterranean is increasing.Holothuria polii, Holothuria tubulosa, Holothuria mammata and Holothuria arguinensis are the new targetspecies. The scarce biological and ecological knowledge on these species along their geographical distri-bution, is a major problem for their fisheries management. To address it, we carried out a morphometricstudy to describe the baseline population size structure, focused on the length–weight relationship andsize–weight distribution.In the NE Atlantic, the largest mean size and heaviest mean weight of H. mammata and H. arguinensiswere found in localities with upwelling, but another factors could be influencing on these...

  14. Genetic differentiation of Elysia timida (Risso, 1818) populations in the Southwest Mediterranean and Mar Menor coastal lagoon

    González-Wangüemert, Mercedes; Giménez-Casalduero, F.; Pérez-Ruzafa, Á.
    Genetic variation at 10 enzyme loci was analysed in Elysia timida sacoglossan mollusc samples, originating from both coastal lagoon and marine sites. The observed heterozygosity ranged from 0.390 (Los Urrutias) to 0.277 (Tabarca). Marine and coastal lagoon populations were characterised by exclusive alleles. Examination of the spatial structure was performed using Nei’s distances and F-statistics, and indicated significant genetic differences between marine groups and coastal lagoon populations. Multivariate analysis of allele frequencies also suggested that different arrays of genotypes prevail in coastal lagoon samples compared to marine ones.

  15. Genetic differentiation and gene flow of two sparidae subspecies, Diplodus sargus sargus and Diplodus sargus cadenati in Atlantic and south-west Mediterranean populations

    González-Wangüemert, Mercedes; Pérez-Ruzafa, Á.; García-Charton, J. A.; Marcos, C.
    A total of nine enzymes coded by 14 loci were assayed for each of six populations (from the north-eastern Atlantic and the Mediterranean) of two sea bream subspecies (Diplodus sargus sargus and Diplodus sargus cadenati). Diagnostic alleles were observed for each subspecies, although there were several common alleles. Estimates of variance in allele frequencies among samples (FST) revealed significant differences (P<0.05) among both subspecies. Genetic divergence was found between Atlantic and Mediterranean samples: values for genetic distances were higher than 0.163. Furthermore, D. sargus cadenati populations displayed a higher mean weight and length than D. sargus sargus populations and significant...

  16. Genetic differentiation in two cryptic species of Ostreidae, Ostrea edulis (Linnaeus, 1758) and Ostreola stentina (Payraudeau, 1826) in Mar Menor Lagoon, southwestern Mediterranean Sea

    González-Wangüemert, Mercedes; Pérez-Ruzafa, A.; Rosique, M. J.; Ortiz, A.
    Ostrea edulis is a target species for aquaculture but its hatchery has suffered as a result of the lack of morphological differentiation between individuals with a low growth and those that reach commercial size. Two sympatric species of oysters, Ostrea edulis and Ostreola stentina, have been reported at the Mar Menor Lagoon, Spain. A third nominal species, Ostreola parenzani, is now considered a synonym of O. stentina. The external morphology of O. edulis and O. stentina is very similar and this prevents their differentiation at the morphological level, except for maximum size. Oysters were collected from 3 locations along the...

  17. Genetic differentiation of Diplodus sargus (Pisces: Sparidae) populations in the south-west Mediterranean

    González-Wangüemert, Mercedes; Pérez-Ruzafa, Á.; Marcos, C.; García-Charton, J. A.
    Allozyme analysis of tissue samples of 1249 white sea bream Diplodus sargus from five localities of the south-west Mediterranean revealed a high degree of genetic polymorphism. The observed heterozygosity ranged from 0.4182 (Cape of Palos) to 0.3138 (Tabarca). Several populations were characterized by unique alleles. Examination of the spatial structure was performed using Nei’s distances and F-statistics, and indicated genetic differences between groups. One group, which clustered Tabarca and Guardamar, could be explained by the small geographical distance between them. Mazarrón and Cape of Palos samples showed genetic divergence from other samples (Guardamar, Tabarca and Águilas) and this difference may be as a result of local...

  18. Preliminary analysis of the genetic variability of two natural beds of the Scallop Euvola ziczac (Linnaeus, 1758) in Brazil

    González-Wangüemert, Mercedes; Pezzuto, Paulo Ricardo; Borzone, Carlos Alberto
    Euvola ziczac (formerly Pecten ziczac), a simultaneous hermaphroditic scallop was heavily fished in Brazil between 1972 and 1980. The production peaked in 1980 with 8,800 tons and was followed by the total collapse of the resource. In order to investigate the possible loss of genetic variability of the stock associated to overfishing and self-fertilization, the polymorphism of phosphoglucomutase (PGM) and glucose phosphate isomerase (GPI) was analyzed by electrophoresis of the adductor muscle of scallops from São Francisco (26° 20.583S; 48° 16.507W) and Bom Abrigo (25° 28.735S; 47° 37.621W) beds; the southern and northern extremes of the scallop fishing ground, respectively. Animals from São Francisco showed a strong...

  19. Novel polymorphic microsatellite loci for a new target species, the sea cucumber Holothuria mammata

    Henriques, Filipe F.; Serrão, Ester A.; González-Wangüemert, Mercedes
    With traditional finfish fisheries declining and pushing transition to new invertebrates target species, sea cucumbers have been heavily explored, suffering global overexploitation and worldwide depletion of their stocks. Nowadays, holothurians from the Mediterranean Sea and NE Atlantic Ocean are being exported to Asian markets. The scarce knowledge about their biology, population dynamics, ecology and genetics, is promoting defective management of their fisheries. We report the development of 9 novel polymorphic microsatellites markers for Holothuria mammata and characterized them by testing in three different sample locations. All nine microsatellites revealed high polymorphism and diversity, with high number of alleles, ranged from 11 to 22 and expected heterozygosity,...

  20. Using a modified Nordmøre grid for by-catch reduction in the Portuguese crustacean-trawl fishery

    Fonseca, Paulo; Campos, Aida; Larsen, Roger B.; Borges, Teresa C.; Erzini, Karim
    By-catch and discards are a common problem to all fisheries. Recent studies of the Portuguese crustacean-trawl fishery show that discards average 70% of the total catch. This situation poses a threat not only to the management of target and commercial fish by-catch species stocks, but also in terms of the ecosystem impact of the discarded species whose survival is generally low. Previous attempts to address this problem by using oblique separator mesh panels associated with square-mesh windows, or square-mesh windows alone, provided encouraging results, but these are unlikely to have commercial applicability at present. Therefore, we tested the efficiency of a modified Nordmøre grid in...

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