Population density of Perna perna and Stramonita haemastoma mollusks and the echinoid Echinometra lucunter in reefs rocky of Santos Bay.

Sarah Raquel Ferlin de Deus, Júlia Costa Alves, Nathalia Sousa Motta, Luiz Miguel Casarini

Abstract


The extractive activities by local communities on the natural banks of Perna perna and Stramonita haemastoma and consumption of Echinometra lucunter may increase leading to depletion of local stock. The aim of this study was to evaluate the densities of the mussel Perna perna, the sea urchin Echinometra lucunter and the gastropod Stramonita haemastoma using photoquadrat based sampling and scuba of the intertidal region on the island of Palmas, Santos Bay, São Paulo. Monthly during the spring and summer of 2011- fall and winter of 2012, in spring tides, were obtained photoquadrat of the rocky reefs around the island,.The images were analyzed in software Coral Point Count with Excel extensions (CPCE) to estimate the coverage area of the species, and the software Image Tool® for quantification of individuals in photoquadrats. Then was performed the nonparametric test Kruskal-Wallis and parametric test ANOVA to check for possible differences between the densities and seasons. The results indicate that the total length of S. haemastoma and E. lucunter, and the density of S. haemastoma and P.perna were statistically significant over de seasons and places of the island (ANOVA P = 0.001). We need to keep the monthly monitoring of the density of the three species because they are fish resources widely used for consumption in coastal communities, and in the case of S. haemastoma the smaller specimens are also used for bait for angling. As prevention against the total depletion of local sotcks is necessary monthly studies about the population density, so that in future, if required, be prepared a management plan suitable recovery of the species.

 

Keywords: Stramonita haemastoma, Perna perna, Echinometra lucunter, poulation density

 


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