The mud crab fishery of the Sundarbans mangrove of Satkhira district (south-western Bangladesh); biological traits to manage the resource
Paper Details
The mud crab fishery of the Sundarbans mangrove of Satkhira district (south-western Bangladesh); biological traits to manage the resource
Abstract
Mud crab is one of the important commodities in the coastal region of Bangladesh but less understood about their abundance and biological traits. The present study described the relative abundance and the biological traits like size distribution, ovarian maturity size, breeding periodicity, etc. of mud crab (Scylla olivacea) to propose a suitable management guideline. Samples were taken between October 2017 and October 2018 from different stations of Satkhira district. The average mud crab density was estimated 481.57 ± 221.34 crabs/ha which represent the average biomass as 28.85 ± 12.88 kg/ha. The crab density was higher in the deeper mangroves than the nearby mangroves and rivers. A total of 874 individuals were assessed and sample individuals showed mostly under the size-class of 70-79 mm internal carapace width (ICW). The female crabs were dominated (57%) throughout the study period and the sex ratio was 1: 1.33. The 47% individuals were mature (U-shape) according to their abdominal flap shape and this finding also reaffirmed by the internal observation of ovaries. The 50% females attain ovarian maturation at the size of 84.98 mm ICW. The species breed round the year but according to their gonadal development frequencies (%) and gonad somatic index (GSI), it was noticed that they might have two peak breeding seasons i.e. winter (November to February) and rainy season (June to July). Thus, it may be suggested that the female mud crab should not be harvested<85mm ICW and the season restriction time might be revised for the coastal areas of Bangladesh.
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Md. Sherazul Islam, 2019. The mud crab fishery of the Sundarbans mangrove of Satkhira district (south-western Bangladesh); biological traits to manage the resource. Int. J. Biosci., 14(5), 357-368.
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