Imposex Incidence in Gastropod Species from Santa Marta Coastal Zone, Colombian Caribbean Sea

Imposex is a phenomenon widely associated with environmental exposure to organotin compounds which were quite common components of antifouling paints applied on boats and ship hulls. Here we study the incidence of imposex in neogastropods and its relation with water quality and maritime traffic in the coastal strip of Santa Marta, Colombia. Imposex was determined via specialized indexes and related to the organisms' size, somatic conditions, variables of water quality and maritime traffic, in a space-time assessment. There was evidence of imposex in five species Plicopurpura patula, Vasula deltoidea, Stramonita haemastoma, S. floridana, and Gemophos auritulus. Purpura patula and Vasula deltoidea species were found in all sampling sites. The results have proved that imposex is highly influenced by the maritime traffic variable, with greater prevalence during the dry season, and with P. patula being more sensitive than V. deltoidea.

[Morfogeometry shell crab Damithrax spinosissimus (Decapoda: Mithracidae) on three islands in the southwestern Caribbean]

The Caribbean King Crab, Damithrax spinosissimus is a fishery resource, but few biological studies are available. Its patchy distribution, and the high environmental heterogeneity due to the oceanographic, landscape, and ecological characteristics of the Caribbean Sea, can favor the phenotypic variability according to the geographic origin. For this reason, the objective of our study was to determine morphometic variability in the carapace of the crabs from three Southwestern Caribbean islands: Providence, Rosario and San Bernardo. The former has an oceanic influence, whereas the two latter islands, which are closer to the mainland, have more influence of the coastal dynamic. A total of 276 individuals from the three islands were captured and photographed: 103 females and 173 males; their variation was analyzed from 12 anatomical landmarks marked on one half of the carapace. The differences in the carapace size were calculated using a Fisher’s pairwise comparison; the allometric effect was calculated by Multivariate Regression Analysis; and the Allometric model via Multivariate Analysis of Covariance. The average shape was calculated from the relative wraps RW obtained through PCA analysis; and the Euclidian distances between the shape averages, were used to construct a tree using the Neighbour-Joining algorithm over 10 000 permutations. The results showed significant differences in the size and shape of the carapace between sexes and among the three islands. The differences in the shape of the crabs from Providencia were significantly greater than those found between the crabs of Rosario and San Bernardo. These results can be explained inclusively due to the genetic differences and phenotypic plasticity, due to environmental heterogeneity of the sector. This study, the first of its kind, is a contribution to the knowledge of the species. We concluded that different management strategies should be differently adopted in each of the three studied islands.

[Hermit crabs (Anomura: Paguroidea) distribution patterns in the Colombian Caribbean Sea]

Hermit crabs represent the marine life in the Colombian Caribbean, and are important for the dynamic equilibrium maintenance in ecosystems, the ecological interactions and their impact on food web stability. Generally, in order to come up with some conservation strategies, strong bio-geographical information is needed for poll cies definition. With this aim, this study analyzed the distribution patterns of hermit crabs in the Colombian Caribbean Sea. through classification and spatial ordination multivariate analyses, using historical records from years 1916 to 2006. Besides, the world distribution of Colombian species and their geographic affinity in the Caribbean and Western Atlantic were identified. The results show deep differences between coastal and continental slope faunas, and latitudinal differences in the assemblages, with the identification of three groups: Northeast. Center and Southwest. The differences in faunal composition that support these three groups were determined. Based on maps of the Colombian marine ecosystems, it was found that the main factors affecting the distribution of hermit crabs were the Caribaná slope (depth), water-mass temperature, Guajira sea-grass beds, and particular conditions of "Coralline Archipelagos" and "Darién" eco-regions. Colombian hermit crab fauna is more related to the North Atlantic and the Antilles, than to the South Atlantic and the Gulf of Mexico. Additionally, geographical sub-provinces in which Colombia is included, these were found as transition zones among Northern and Austral subprovinces of the Greater Caribbean.

[Accumulation and depuration of aldrin in the oyster Crassostrea rhizophorae, of the Ciénaga Grande de Santa Marta (Colombian Caribbean)]

Laboratory experiments were conducted at different salinities (35, 26 and 17/1000) to determine accumulation and depuration rates of the organochlorine compound aldrin by the oyster Crassostrea rhizophorae, Ciénaga Grande de Santa Marta (Colombian Caribbean). Residual levels were detected in tissues after 24 hours of exposure, showing increases directly related to the exposure concentration. For all the exposure concentrations the highest retention values were measured at 26/1000 salinities, followed by 17/1000, and the lowest values at the highest salinity. The highest bioconcentration values were 96115.5 (at 26/1000), 37938.9 (at 17/1000), and 22605.1, (35/1000) times the environmental concentration. The depuration process varied across salinity levels. At 26/1000 there was a clear decrease in the residual levels during the first five days, eliminating in this period the same amount as oysters kept at 17/1000 for 20 days and surpassing the amount eliminated by those kept at 35/1000 for 20 days. A rapid decrease in the amount of residues is followed by a slow elimination of the aldrin remaining in tissues.

[Concentrations of trace metals in Ariopsis bonillai (Pisces: Siluriformes) of Santa Marta, Colombian Caribe]

To determine changes in the contents of some heavy metals (Cd, Zn, Cu) in the fish Ariopsis bonillai, at Ciénaga Grande de Santa Marta, Colombia, monthly samples were taken between July 1987 and June 1988. The highest concentrations in the muscle appear between November and February (4.24 micrograms Cd/g, 109.4 micrograms Zn/g and 13.3 micrograms Cu/g), during the periods of lower salinity, at the end of the rainy season, and at the beginning of the dry season. Metals were measured also in the liver: values for Zn and Cu were ten times higher than in the muscle. About the first half of the year, the values tend to be similar. Cd differences were not as strong as for the other metals.