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- 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.
- ENiRG: R-GRASS interface for efficiently characterizing the ecological niche of species and predicting habitat suitabilityPublication . Cánovas, F.; Magliozzi, C.; Mestre, F.; Palazón, J. A.; González-Wangüemert, MercedesAt the base of species distribution modelling is the ecological niche concept, which describes species’ response to distribution of resources. The ecological niche factor analysis, which is implemented in ENiRG, allows to reconstruct species’ niche from a set of environmental variables, describing the suitability of the habitat where species occurs. ENiRG overcomes the inefficient management of large volumes of spatial information from wide study areas, high resolution or high number of environmental descriptors. This package also offers the possibility of habitat suitability classification, projection of distributions under different past or future climate scenarios and a GUI to access the functionalities.
- Temporal genetic variation in populations of Diplodus sargus from the SW Mediterranean SeaPublication . Gonzalez-Wanguemert, Mercedes; Pérez-Ruzafa, Á.; Cánovas, F.; García-Charton, J. A.; Marcos, C.Population genetic studies on white sea bream Diplodus sargus have revealed different patterns in the subdivision of populations in the Mediterranean Sea. However, the stability of observed allele frequencies over time remains poorly tested. The aim of this study was to show that the genetic structure of D. sargus could significantly change over time by analysing temporal variations in allozymes. In order to determine temporal variation in the genetic structure of 5 natural D. sargus populations in the SW Mediterranean, we screened 14 allozyme loci. Our main finding was the significant genotypic differentiation among cohorts (year-classes) in the Guardamar (FST = 0.012; p < 0.001) and Cape of Palos (FST = 0.008; p < 0.001) populations. The differentiation observed in the present study when considering pair-wise comparisons between cohorts is similar to that of all populations throughout the Mediterranean Sea. Our results suggest that microgeographical variations, also known as ‘chaotic genetic patchiness’, could occur in D. sargus populations from the SW Mediterranean. The recruitment of genetically variable cohorts at 1 site each year may account for these variations. We also discussed alternative explanations for this genetic pattern. This study confirms the importance of understanding the ecology, behaviour and environment of fish populations when investigating population genetic structure. Our results also highlight the importance of incorporating temporal samples when conducting population structure studies.