Diversity indices and distribution of brachyuran crabs found in the lagoon waters of Sonmiani, Balochistan

A total of 8 species of Brachyuran crabs was recorded,crabs belong to the family Portunidae were dominant and represented by 6 species. Portunus pelagicus and Portunus sanguinolentus were found throughout the years.Various ecological indices were calculated through the obtained data. The diversity ranged from 0.63-1.64, the richness varied from 0.84-1.76, the evenness ranged from 0.1-0.35, the index of dominance varied from 0.36-0.73. Maximum diversity was recorded during Pre monsoon (yr. 2005-06). The ecological indices were positively correlated with environmental parameters.