Imposex in the marine snail Stramonita haemastoma - Gastropoda: Muricidae) on the central coast of Peru

The masculinization of females due to imposex in gastropods has been registered in more than 260 species worldwide. Field studies indicate that the masculinization of females has been mainly attributed to TBT. It is for this reason that we have evaluated the incidence of imposex in the Stramonita haemastoma snail on the Naplo beach, Pucusana, Lima on the central coast of Peru. The percentage of imposex was 78.03%. The index of relative penile length (RPLI) was equal to 25.64%. A statistically significant relationship was found between the length of the shell and the length of the penis in males, but not in females, which indicates that the length of the penis depends on the exposure to TBT and not the length of the shell. Differences were found in the length of the penis of the females according to degrees of VSDI (sequence index of the vas deferens). VSDI values were found mainly in grades I and II (mean VSDI of 1.84), indicating that females with imposex are found in the initial stages of the phenomenon, and reproductive failure still does not occur. Stramonita haemastoma is considered a good bioindicator of organotin (OT) contamination because it develops imposex rapidly because it is very sensitive to the presence of these xenobiotics in its environment.