Prediction efficiency of the hydrographical parameters as related to distribution patterns of the Pleuromamma species in the Indian Ocean

Abstract

Among species of the genus Pleuromamma, P. indica was the only species existing in the Northern Indian Ocean. In the rest of the Indian Ocean the most abundant species was P. gracilis, and P. abdominalis was almost homogeneously distributed. Multiple regression model of P. indica abundance on the parameters: temperature, salinity, dissolved oxygen and phosphate-phosphorus could explain more than 85% of the variation in the predicted abundance, while those of 8 species obtained from the equatorial region and southern coast off South Africa could explain only 30% of the variations in the predicted total abundance and it was attained only when average values of the parameters were considered in both cases. Hence average values of the parameters were the optimal values of the parameters to be considered for maximum information about the distribution of pleuromamma species. High diversity and low dominance (high evenness) were observed in the distribution of Pleuromamma species in the equatorial region