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- Setting preliminary biometric baselines for new target sea cucumbers species of the NE Atlantic and Mediterranean fisheriesPublication . González-Wangüemert, Mercedes; Valente, Sara; Henriques, Filipe; Domínguez-Godino, Jorge A.; Serrao, EsterCommercial 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 results. In theMediterranean, Girona and Mallorca showed the heaviest specimens of H. polii, H. tubulosa and H. mam-mata, and the smallest were registered in Crete and Kusadasi. Significant differences in length and weightbetween populations were found for each species. These results could be linked with local environmentalconditions. Size frequency distribution was multimodal for all species except for H. mammata; the weightfrequency distribution was only unimodal for H. polii and H. mammata.This study provides novel data, helpful for stock and population assessment which could support theimplementation of effective management for the European sea cucumber target species.
- Genetic differentiation of Diplodus sargus (Pisces: Sparidae) populations in the south-west MediterraneanPublication . 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 current systems and larval dispersal.
- Modelling spatial and temporal scales for spill-over and biomass exportation from MPAs and their potential for fisheries enhancementPublication . 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, MercedesMarine 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 individuals to the fished area. The model showed that biological responses inside marine reserves appear to develop quickly, reaching mean levels within a short (1–5 year) time period. Mean population abundance is always higher inside the reserve and highlights the effectiveness of protection, particularly when there is strong fishing pressure outside the reserve. However, reserves smaller than 2000 m radius show significantly lower levels of abundance inside than larger sites. Large MPAs (i.e. about 2000 m in radius) offer nearly the maximum capacity for recovery (close to 100% of the system carrying capacity) and nearly the maximum flux of individuals per unit boundary length. Very large MPAs (i.e. larger than 6000 m in radius) could be a guaranteed means of providing resilience in order to prevent population crises, with the added advantage that the flux of individuals is slightly higher at larger distances from the boundary. However, in practice they provide no further advantage towards increasing the density of individuals or the exportation of biomass, and a network of smaller MPAs could be more beneficial, both from the point of view of conservation and of benefits to fisheries.
- First record of the Atlantic blue crab Callinectes sapidus (Crustacea: Brachyura: Portunidae) in the Segura River mouth (Spain, southwestern Mediterranean Sea)Publication . González-Wangüemert, Mercedes; Pujol, Juan AntonioA single male individual of Callinectes sapidus (Crustacea, Decapoda, Portunidae) was collected on 6 December 2014 in the Segura River mouth in southeastern Spain. Information on collection site, DNA barcoding, and its present distribution and dispersal strategies are provided.
- Genetic differentiation in two cryptic species of Ostreidae, Ostrea edulis (Linnaeus, 1758) and Ostreola stentina (Payraudeau, 1826) in Mar Menor Lagoon, southwestern Mediterranean SeaPublication . 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 Mar Menor Lagoon and examined for variation at the PGI locus. Principal component analysis of allo-zyme data revealed the existence of two groups, which confirms the presence of two species: Ostrea edulis and Ostreola stentina. The genetic variability of the glucose-6-phosphate isomerase (PGI) locus was also compared in Ostrea edulis and Ostreola stentina from the Mar Menor Lagoon. Ostrea edulis has high levels of homozygosis and shows an important deviation from the Hardy-Weinberg equilibrium. Ostreola stentina shows high heterozygosis and significant differentiation among coastal lagoon samples. The allele frequencies at the PGI locus can be used as a diagnostic character at the species level.
- Effects of fishing protection on the genetic structure of fish populationsPublication . Pérez-Ruzafa, Ángel; González-Wangüemert, Mercedes; Lenfant, Philippe; Marcos, Concepción; García-Charton, José AntonioMarine 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 higher allelic richness. The lower levels of heterozygosis and higher heterozygote deficit showed by islands compared with coastal areas makes clear the importance of considering the connectivity processes when designing a MPA.
- Identification of weakfish Cynoscion (Gill) in the Bay of Panama with RFLP markersPublication . 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.
- A new record of Holothuria arguinensis colonizing the Mediterranean SeaPublication . González-Wangüemert, Mercedes; Borrero-Pérez, GiomarHolothuria 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.
- Novel polymorphic microsatellite loci for a new target species, the sea cucumber Holothuria mammataPublication . Henriques, Filipe; Serrao, Ester; González-Wangüemert, MercedesWith 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, between 0.52 and 0.92. Significant genetic differentiation was found between populations. These microsatellites are providing valuable information which could be applied to fisheries management including, identification of stocks, assessment of their genetic diversity, estimation of gene flow and monitoring the fishery effects on exploited populations.
- A new species for sea cucumber ranching and aquaculture: breeding and rearing of Holothuria arguinensisPublication . Domínguez-Godino, Jorge A.; Slater, Matthew J.; Hannon, Colin; González-Wangüemert, MercedesMulti-species sea cucumber fisheries, including the speciesHolothuria arguinensis, have developed recently in the North-eastern Atlantic and Mediterranean Sea. In this context, the current study evaluated the potential use of H. arguinensis in aquaculture and to enhance natural populations, describing the embryonic and larval development for a better understanding and application in marine conservation and population genetics. Wild broodstock collected in Ria Formosa (37°0′33.92″N, 7°59′44.99″W; Faro, South Portugal) was induced to spawn using established methodology of thermal stimulation from June to August. The larval development under controlled conditions exhibited the classic five stages described for most aspidochirote holothurians, reaching the juvenile stage after 18 days post-spawning. Low mortality was registered during the pelagic larval stage, however high mortality (85–95%) was registered at doliolaria and juvenile stages. Results indicate that H. arguinensis is suited to hatchery rearing for aquaculture and enhancement of natural populations. Nevertheless, as this is the first European sea cucumber species reproduced in a hatchery, further research is required to improve the survival of post-settlement stages and optimize the rearing of juveniles.