Rajib Hasan* and Harun Or Rashid
Department of Zoology, Biological sciences, University of Dhaka, Dhaka 1000, Bangladesh
Received: 13 May, 2016; Accepted: 26 May, 2016; Published: 27 May, 2016
Rajib Hasan, Department of Zoology, Biological sciences, University of Dhaka, Dhaka 1000, Bangladesh, E-mail;
Hasan R, Rashid HO (2016) A Study and Availability Assessment of Freshwater Crabs in the Hill Streams of Bangladesh. Int J Aquac Fish Sci 2(1): 018-022. DOI: 10.17352/2455-8400.000014
© 2015 Hasan R, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Climate change; Fish production; Sustainable aquaculture; Food security
A study of crabs was conducted at eight hill streams, located in three different districts of Bangladesh, during January to December, 2012 with a view to assess the availability and to study the taxonomy of freshwater crabs. The study investigated species diversity which includes their taxonomic description, biometric data, habitat, ecological note, distribution, and ecological role. The specimens were collected in different times covering the major seasons rounded the year by using various fishing gears such as cast net, push net, dip net, seine net and trap. A total four species of freshwater crabs under two families (Potamidae and Grapsidae) were recorded. The identified four crabs were Sartoriana spinigera, Sartoriana trilobata, Labothelphusa wood-masoni and Pyxidognathus fluviatilis. Among these the first three were under the family Potamidae and the last one under the family Garapsidae. Sartoriana trilobata was the dominant species in the hill streams of Bangladesh.
Bangladesh is a country which is mostly low in elevation and the hill areas occur in the Khagrachari, Rangamati, Bandarban, Chittagong, Cox's Bazar, Mymensingh, Netrokona, Sylhet, Moulavibazar and Habiganj districts. These regions include a remarkable area of hilly rivers, lakes and streams and waterfalls that are identified to be an excellent playground of biodiversity. Various small and moderately large streams have been found all over the country which are very rich of ecologically important species. So streams of hilly areas are predicted to be the biodiversity hot spots in the country containing a high diversity of crab species that have yet to discover.
Freshwater crabs are found throughout the tropical and sub-tropical regions of the world. They live in a wide range of water bodies, from fast-flowing rivers to swamps, as well as in tree boles or caves. The majority of species are narrow endemics, occurring in only a small geographical area. This is at least partly attributable to their poor dispersal abilities and low fecundity  and to habitat fragmentation caused by the world's human population . Freshwater crabs of Bangladesh can distinguished from false crabs by not having 5th pair of periopods totally or partly having concealed beneath the carapace, the antennae were always placed between the inner margin of orbit and fused pterygostomial region with endestome . In most decapods, the gonopores (sexual openings) are found on the legs. However, since crabs use the first two pairs of pleopods (abdominal appendages) for sperm transfer, this arrangement has changed. As the male abdomen evolved into a narrower shape, the gonopores have moved towards the midline, away from the legs, and onto the sternum . The hilly crab faunas of Bangladesh have never been broadly surveyed by researchers. It is necessary to know the biodiversity of freshwater crabs in hilly region of Bangladesh for conservation purpose. So the present study was focused to identify crab species in the selected waterfalls, rivers and streams in the hilly areas as well as to assess the status and diversity of crabs in relation to their habitats.
Materials and Methods
Study sites and period
The research was conducted in eight selected sites of three hilly districts of Bangladesh such as Sangu River in Bandarban, Shailopropat Waterfall in Bandarban, Rijuk Waterfall in Bandarban, Boga Lake in Bandarban, Himchori in Cox's Bazar, Barachara in Cox's Bazar, Kudung Cave in Cox's Bazar and Madhobkunda Waterfall in Moulvibazar (Figure 1). The study was conducted from January 2012 to December 2012 followed by the various seasons of Bangladesh with four times of Crabs collection.