The Shark fishery is a newly introduced single fishery almost all the river system estuarine and the sea and contributing above 0.18% of the total fish production in Bangladesh. In Chittagong and Cox’s Bazar district about 70-100 boats are engaged in this commercial fishery of the Marine territory. Once sharks were captured as a by catch of gill net, demersal trawlinh (bottom trawling) and shrimp trawling, long line, estuarine set beg net (ESBN) and marine set beg net (MSBN). But now a days the shark fishing activities are confined to the sea by newly introduced net is “Shark net”. This fishery constrain sharks skates and rays under the class condrichtheys (Fish whose skeleton is made of cartilage). There are approximately 600 species of cartilaginous fish and are the lowest living vertebrates in the world. Most sharks and rays are marine but a few live in tropical rivers and come in brackish waters or fresh water. In the world there were 50,000 Metric tons to 70,000 Metric tons of chondrichthyes (Elasmobranch) has been caught through the year. All the sharks and rays are caught from the shore base in Artisanal fisheries and commercially in off-shore base. Generally the abundance of sharks are 10-250 meter depth of the sea (FAO-1984). Significant amount of shark products are straddled through the trans boundary movement from Bangladesh to neighboring countries. China, Japan, India, Myanmar, Singapore and Thailand shark products (hide, fins, crude oil, meat) exported at different region and Bangladesh are decreasing rapidly. Not only shark fins, oil, meat but also shark skins are exported from Bangladesh and this plays an important role in the economy. Shark is being hunted indiscriminately in the south-western and south-eastern coasts of Bangladesh threatening marine ecosystem even though catching shark is banned under the Conservation Act. Catching shark is now a lucrative business for a large number of fishermen as shark skin, meat, fin, teeth, bone is sold at high prices abroad. More and more fishermen are attracted to shark netting as it often brings more profit than catching fish.
Although little is known about many shark species, the river sharks of the genus Glyphis are an especially enigmatic group. Three different species of river sharks were recognized throughout most of the 20th century: the notorious Ganges man-eater Glyphis gangeticus (Müller and Henle, 1839) (1), represented by one dried skin lectotype and one alcohol-preserved paralectotype; the speartooth shark Glyphis glyphis (Müller and Henle, 1839) (1) of unknown geographic origin represented by a single dried skin holotype, two small, poorly preserved specimens, and a handful of dried jaws; and the Irrawaddy shark Glyphis siamensis (Steindachner, 1896) (2), which originated from the mouth of the Irrawaddy River in Myanmar and is known only from its alcohol-preserved holotype.
Glyphis gangeticus (Müller and Henle, 1839)
The river sharks of the genus Glyphis, widely feared as maneaters throughout India, remain very poorly known to science. The group constitutes five described species, all of which are considered highly endangered and restricted to freshwater systems in Australasia and Southeast Asia. DNA sequence data derived from 19th-century dried museum material augmented with contemporary samples indicates that only three of the five currently described species are valid; that there is a genetically distinct, but as-yet-undescribed, species recorded in Bangladesh and Sarawak in Malaysian Borneo; and that these iconic and mysterious sharks are not restricted to freshwater at all but rather appear to be adapted to both marine and freshwater habitats.