he transformed abundance index was calculated by means the formula A = Ln(x+1), where, x = mean number of individuals and Ln = reperian logarithm. The abundance index tended to increase with the temperature elevation and it was high in 31.6 to 33.2% of salinity. The abundance index for both dissolved oxygen and organic material contents were characterized by normal curve. The individuals were abundant in the first two strata of depth. With relation to granulometric fraction, the animals were more abundant in subareas with gravel and very coarse sand than the others. Based on this results and field observations it can be concluded that the presence of P. spinimanus is associated to a group of environment factors among them the texture (gravel and very coarse sand) and to protected sites in the bay, characterized by a relatively calm water.
