A Comparison of shell size and meat weight between population of the bivalve Anadara antiquata (Linnaeus 1758) from four sites experiencing different levels of exploitation pressure in Zanzibar

Abstract

A comparative study on the shell size and meat weight between Anadara antiquata populations harvested from four intertidal mud flats subjected to varying exploitation pressure in Zanzibar was undertaken between August and December 2000. An analysis of the data from the four study locations Mazizni, Mbweni, Kisakasaka, and Jambiani showed that much smaller sized Anadara , with low meat weights were being harvested from Mazizini and Mbweni in comparison to those harvested from Kisakasaka and Jambiani. The first two sites were areas in which there was heavy exploitation of the animals in comparison to the last two. Mazizini and Mbweni were always found to be occupied by shell collectors on almost all low tides .The availability of alternative livelihood activities at Kisakasaka and Jambiani appeared to be responsible for the reduced exploitation pressure on the cockles, reflected by the presence of comparatively large and heavy animals. The results of this investigation are given together with management suggestions including the introduction alternative livelihood activities, which may lead to better growth and meat yield of this locally valuable molluscs.