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- Improving the fitness of Holothuria arguinensis larvae through different microalgae dietsPublication . Dominguez-Godino, Jorge A.; Gonzalez-Wanguemert, MercedesDevelopment and design of adequate feeding protocols on sea cucumber larvae are necessary for improvements on larvae growth, survival and production of competent juveniles. This work assessed the Holothuria arguinensis larvae growth and survival, fed with three different single microalgae diets of Chaetoceros calcitrans, Isochrysis galbana and Tetraselmis chui, and two microalgae diets based on a combination of C. calcitrans and T. chuii (C:T 1:1) and C. calcitrans, T. chuii and I. galbana (C:T:I 1:1:1) during 2 months. Holothuria arguinensis larvae fed with T:C:I, showed higher survival and larger larval and stomach sizes than the ones fed with the other diets. Comparing the results obtained from the single diets, H. arguinensis larvae fed with I. galbana grew and survived better during the first 5 days. However, higher growth was obtained on the larvae fed with C. calcitrans from day 5 to day 12 since this day, larvae fed with T. chuii showed the largest size. These results could be related to the different microalgae size and morphology, in addition to the nutritional value of the different microalgae used. However, no competent larvae that metamorphosed into doliolaria were obtained during this experiment. The tanks used were transparent, which could be causing light stress to the larvae, since competent larvae were obtained in opaque production tanks in our aquaculture installations during the same time period. The combined diet of C. calcitrans, T. chuii and I. galbana (C:T:I) could improve the growth and larvae competency of H. arguinensis.
- Genetic and oceanographic tools reveal high population connectivity and diversity in the endangered pen shell Pinna nobilisPublication . Wesselmann, Marlene; Gonzalez-Wanguemert, Mercedes; Serrao, Ester A.; Engelen, Aschwin H.; Renault, Lionel; Garcia-March, Jose R.; Duarte, Carlos M.; Hendriks, IrisFor 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.
- First report of the nutritional profile and antioxidant potential of Holothuria arguinensis, a new resource for aquaculture in EuropePublication . Roggatz, Christina C.; Gonzalez-Wanguemert, Mercedes; Pereira, Hugo; Rodrigues, Maria Joao; F. G. M. Silva, Manuela; Barreira, Luísa; Varela, João; Custódio, LuísaThis 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.
- Habitat associations and seasonal abundance patterns of the sea cucumber Holothuria arguinensis at Ria Formosa coastal lagoon (South Portugal)Publication . DOMINGUEZ GODINO, JORGE ANTONIO; Gonzalez-Wanguemert, MercedesSea cucumbers have an important economic value and high demand. Despite that, there is a lack of knowledge about their biology, ecology and habitat distribution patterns, which is very important for sea cucumber stock management, establishment and sizing of no-take zones, restocking actions and selection of grow-out areas. This work aimed to determine the density, abundance and habitat associations of Holothuria arguinensis for a better understanding of its distribution along the coastal lagoon Ria Formosa and to select suitable areas for grow-out. In the duration of a year, monthly visual censuses were performed in two locations at Ria Formosa along the intertidal zone. The number and length of H. arguinensis ' individuals found were registered, and the coverage of algae and seagrass was estimated. It was found that H. arguinensis was distributed along the lower intertidal zone, linked to Zostera noltii meadows on muddy and sandy bottoms. These areas showed the densest population and the largest sizes of H. arguinensis. However, during the warmer months, H. arguinensis seemed to migrate to deeper waters in the channels, to avoid exposition to high temperatures and solar/UV irradiance during low tides. Areas located in the lower intertidal zone with Z. noltii meadows on sand-muddy bottoms should be selected for H. arguinensis grow-out sites.
- Epidemiology of skin ulceration disease in wild sea cucumber Holothuria arguinensis, a new aquaculture target speciesPublication . Cánovas, F.; DOMINGUEZ GODINO, JORGE ANTONIO; Gonzalez-Wanguemert, MercedesInterest in wildlife epidemiology has increased in recent years. The control of diseases is critical for the survival of natural populations of economically valuable species. The present study is the first investigation of the etiology and epidemiology of skin ulceration disease in the sea cucumber Holothuria arguinensis, a new target species for fisheries and aquaculture in Europe. Bacterial cultures and molecular techniques were used to characterize this disease in animals collected during a survey across Ria Formosa Natural Park coastal lagoon in southern Portugal. Vibrio gigantis and V. crassostreae, which were both originally identified as disease agents in cultured oysters, were the most commonly isolated species of bacteria. Given that both sampling areas from which symptomatic H. arguinensis were collected were close to open oyster aquaculture facilities, this raises the possibility of an opportunistic infection, perhaps secondary to a decreased immune response caused by biotic or abiotic factors. An increase in prevalence of skin ulceration disease during the warmer season suggests that solar radiation and desiccation due to air exposure during low tide could be a cause of abiotic stress in the lagoon. Distributions of abundance and sizes of H. arguinensis in affected areas showed highest morbidity rates in adults. High fishery pressures throughout the study period could also cause elevations in prevalence and incidence rate of this disease. Skin ulcerative disease is endemic in this coastal lagoon. Disease monitoring is thus essential for the development of a conservation program to ensure the sustainability of fisheries and protection of natural resources.
- Phylogeography of the Atlanto-Mediterranean sea cucumber Holothuria (Holothuria) mammata: the combined effects of historical processes and current oceanographical patternPublication . Borrero-Perez, G. H.; Gonzalez-Wanguemert, Mercedes; Marcos, C.; Perez-Ruzafa, A.We assessed the genetic structure of populations of the widely distributed sea cucumber Holothuria (Holothuria) mammata Grube, 1840, and investigated the effects of marine barriers to gene flow and historical processes. Several potential genetic breaks were considered, which would separate the Atlantic and Mediterranean basins, the isolated Macaronesian Islands from the other locations analysed, and the Western Mediterranean and Aegean Sea (Eastern Mediterranean). We analysed mitochondrial 16S and COI gene sequences from 177 individuals from four Atlantic locations and four Mediterranean locations. Haplotype diversity was high (H = 0.9307 for 16S and 0.9203 for COI), and the haplotypes were closely related (p = 0.0058 for 16S and 0.0071 for COI). The lowest genetic diversities were found in the Aegean Sea population. Our results showed that the COI gene was more variable and more useful for the detection of population structure than the 16S gene. The distribution of mtDNA haplotypes, the pairwise FST values and the results of exact tests and AMOVA revealed: (i) a significant genetic break between the population in the Aegean Sea and those in the other locations, as supported by both mitochondrial genes, and (ii) weak differentiation of the Canary and Azores Islands from the other populations; however, the populations from the Macaronesian Islands, Algarve and West Mediterranean could be considered to be a panmictic metapopulation. Isolation by distance was not identified in H. (H.) mammata. Historical events behind the observed findings, together with the current oceanographic patterns, were proposed and discussed as the main factors that determine the population structure and genetic signature of H. (H.) mammata
- Connectivity patterns inferred from the genetic structure of white seabream (Diplodus sargus L.)Publication . Gonzalez-Wanguemert, Mercedes; Canovas, Fernando; Perez-Ruzafa, A.; Marcos, C.; Alexandrino, PauloThemarine environment seems, at first sight, to be a homogeneousmediumlacking barriers to species dispersal. Nevertheless, populations of marine species show varying levels of gene flow and population differentiation, so barriers to gene flow can often be detected. Weaimto elucidate the role of oceanographical factors ingenerating connectivity among populations shaping the phylogeographical patterns in the marine realm, which is not only a topic of considerable interest for understanding the evolution ofmarine biodiversity but also formanagement and conservation of marine life. For this proposal,we investigate the genetic structure and connectivity between continental and insular populations ofwhite seabreamin North East Atlantic (NEA) and Mediterranean Sea (MS) aswell as the influence of historical and contemporary factors in this scenario using mitochondrial (cytochrome b) and nuclear (a set of 9 microsatellite) molecular markers. Azores population appeared genetically differentiated in a single cluster using Structure analysis. This result was corroborated by Principal Component Analysis (PCA) and Monmonier algorithm which suggested a boundary to gene flow, isolating this locality. Azorean population also shows the highest significant values of FST and genetic distances for both molecular markers (microsatellites and mtDNA). We suggest that the breakdown of effective genetic exchange between Azores and the others' samples could be explained simultaneously by hydrographic (deep water) and hydrodynamic (isolating current regimes) factors acting as barriers to the free dispersal of white seabream(adults and larvae) and by historical factors which could be favoured for the survival of Azorean white seabream population at the last glaciation. Mediterranean islands show similar genetic diversity to the neighbouring continental samples and nonsignificant genetic differences. Proximity to continental coasts and the current system could promote an optimal larval dispersion among Mediterranean islands (Mallorca and Castellamare) and coasts with high gene flow.
- Genetic diversity across geographical scales in marine coastal ecosystems: Holothuria arguinensis a model speciesPublication . Rodrigues, F.; Valente, Sara; Gonzalez-Wanguemert, MercedesCoastal lagoons are considered one of the most productive areas of our planet harboring a large variety of habitats. Their transitional character, between terrestrial and marine environments, creates a very particular ecosystem with important variations of its environmental conditions. The organisms that are able to survive on these ecosystems frequently experience strong selective pressures and constrictions to gene flowwith marine populations, which could contribute to genetic divergence among populations inhabiting coastal lagoon and marine environments. Therefore, the main aims of this study are to asses the genetic diversity and population structure of Holothuria arguinensis across geographical ranges, to test the hypothesis of coastal lagoons as hotspots of genetic diversity in the Ria Formosa lagoon, and to determine the role of exporting standing genetic variation from the lagoon to open sea and their implications to recent geographical expansion events. To reach these objectives, we investigate the genetic structure of H. arguinensis using two mitochondrial DNA markers (COI and 16S) at different spatial scales: i) small, inside Ria Formosa coastal lagoon, South Portugal; 2) large, including most of the geographical distribution of this species (South and Western Portuguese coast and Canary islands); these results will allow us to compare the genetic diversity of lagoonal and marine populations of H. arguinensis. On this framework, its recent geographical expansion events, recorded by Rodrigues (2012) and González-Wangüemert and Borrero-Pérez (2012), will be analyzed considering the potential contribution from lagoonal genetic pool. Non-significant genetic structure and high haplotypic diversity were found inside the Ria Formosa coastal lagoon. Both genes were unable to detect significant genetic differentiation among lagoonal and marine localities, suggesting a high rate of gene flow. The results supported our hypotheses that coastal lagoons are not only acting as hotspots of genetic diversity, but also contributing for the genetic variability of the species, working as a source of new haplotypes and enhancing adaptation to the high variable conditions. Different genetic patterns of colonization were found on H. arguinensis, but they must be studied more deeply.
- New insights into the genetic diversity of zooxanthellae in Mediterranean anthozoansPublication . Casado-Amezua, Pilar; Machordom, Annie; Bernardo, Joao; Gonzalez-Wanguemert, MercedesSymbiotic dinoflagellates of the genus Symbiodinium, also called zooxanthellae, are found in association with a wide diversity of shallow-water anthozoans. The Symbiodinium genus includes numerous lineages, also referred to as clades or phylotypes, as well as a wide diversity of genetic sub-clades and sub-phylotypes. There are few studies characterizing the genetic diversity of zooxanthellae in Mediterranean anthozoans. In this study, we included anthozoans from the Western Mediterranean Sea and by means of internal transcriber (ITS) and large sub-unit (LSU) rRNA markers we corroborate what has been previously identified, demonstrating that phylotype “Temperate A” is very common among host Cnidaria in this basin. Our finding of fixed differences in ITS and LSU markers that correspond to different host taxa, indicate that this clade may comprise several closely-related species.
- Seagrass debris as potential food source to enhance Holothuria arguinensis' growth in aquaculturePublication . Dominguez Godino, Jorge Antonio; Santos, Tamara; H., Pereira; Custódio, Luísa; Gonzalez-Wanguemert, MercedesHolothuria arguinensis aquaculture started to be developed in 2014, being the first sea cucumber species from Europe. However, some aspects of its aquaculture biotechnology, such diets, need to be assessed. This work aimed to evaluate seagrass debris of Zostera noltii and Cymodocea nodosa as food source for broodstock maintenance in tanks, during breeding periods. The given feed rations per tank were calculated as the 30% of the total sea cucumber biomass in each tank and reviewed each week. Then, feed rations of seagrass and sediment were calculated from this value, according to the following percentages: 40% sediment, 15% Z. noltii, 40% Z. noltii, 15% C. nodosa and 40% C. nodosa. H. arguinensis growth, feeding rate and nutritional value were assessed under these diets. H. arguinensis fed with 40% of Z. noltii showed the highest growth (specific growth rate = 0.09 +/- 0.06%/day, absolute growth rate = 0.11 +/- 0.07 g/day) increasing their final weight in 5.86 +/- 3.57% in 57 days. However, the individuals fed with C. nodosa showed a negative growth. H. arguinensis showed a reduction in its feeding rate as the organic matter content in the diets increased. H. arguinensis did not show any important change on proximate composition, protein, lipid, mineral contents and fatty acids profile among the feeding groups, or in comparison with the individuals collected from wild habitat. Therefore, H. arguinensis could be fed with Z. noltii debris during tanks maintenance along breeding period, ensuring its growth and maintaining its nutritional profile.
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