Conchiological survey and analysis of predation by gastropods on bivalves on Guaecá beach, São Sebastião-SP Adriana Martins dos Santos, Judith Font Batalla

Abstract

The marine environment is rich in several aspects besides its beauty, it is home to a great diversity of living species, including molluscs. Most molluscs have a calcareous shell that serves as protection against predators, but there are other organisms capable of piercing the shells of other molluscs. This work aimed to characterize the predation of gastropods in different families of Bivalvia, based on the study of morphology in shells at Praia de Guaecá, North Coast of São Sebastião – SP. Data collection was carried out in the morning at two different times, in January and February 2017. During the observation period we found the species Divaricella quadrisulcata (D’Orbigny, 1842), with the largest number of perforated shells. The January collection presented 8 species of shells, including the Veneridae family, which appears twice in this collection. Among the shells analyzed, the species Divaricella quadrisulcata stood out as it presented 7 perforated valves (46%), out of a total of 15 shells perforated in the month of January. In the February collection, 10 species of shells were found, in which the Veneridae family appears twice in this collection; Species from the Trochidae family also presented the same frequency of occurrence. Among the shells analyzed, once again the species Divaricella quadrisulcata stood out as it had 18 perforated valves, out of a total of 30 perforated shells. With the results presented, we can hypothetically say that there is a very high chance of this food preference happening in the location studied.