Bat fish, Razor fish,Frog crab rediscovered

The Deep Sea Smoky Batfish. Photo: Special Arrangement  

Three unique marine organisms, Deep Sea Smoky Bat fish, Grooved Razor fish and Frog crab, have been re-recorded from Indian waters after a gap of over a century.

Cruises on board ocean research vessel ‘Sagar Sampda' in the Bay of Bengal yielded the species. The specimens were collected off the Andhra Pradesh coast during the cruises held between August and September 2009. It took over a year for the identification and validation of the species, scientists of the Central Marine Fisheries Research Institute here said.

Bat fish was first described by Alfred William Alcock in 1894 after it was spotted in the Bay of Bengal following surveys conducted on board ‘Investigator,' the Royal Indian Marine Survey Ship. The samples were obtained from a depth ranging from 265 metres to 457 metres.

The recent collection of the species came off Tamarapatnam at a depth of 100 metres and after 116 years of its identification, said scientists E. Vivekanandan and R. Jeyabaskaran.

Of the nine Bat fish species available worldwide, four have been reported in India. These species mainly feed on molluscs, marine worms, small crustaceans and occasionally small fishes. Bat fishes are mostly found in Indo-West Pacific, South Africa, Vietnam, Malaysia, the Philippines, Indonesia, Australia, Taiwan and China.

Razor fish, also known as shrimpfish and Pipette feeders, was first reported in India from the Gulf of Mannar by renowned fisheries expert Francis Day in 1878. The rediscovery was from the area off Singarayakonda from a depth of 30 metres. These fish varieties are generally found in coral reefs. The presence of the species in Singarayakonda may be an indication of the possible presence of coral reefs, they said.

The species are mostly found in the Indian Ocean and the Pacific Ocean. So far, only two species are known to science.

The body of these species, which is almost transparent and flattened from side to side, is silvery in colour and has a dark lateral band from head to tail. They have long snouts and sharp-edged belly. The fishes, which generally inhabit muddy bottoms, seek refuge among coral branches or the spines of long-spined sea urchins, researchers said.

Unlike other fishes, they swim vertically and in a synchronised manner with its snout pointing downwards. They feed on small benthic invertebrates, mainly crustaceans. Razor fishes are not used as food, but collected by aquarium hobbyists.

The Frog crab was first described by B. Chopra, former director of the Zoological Survey of India, in 1933 based on a single specimen collected from the Andaman Sea in 1898. The recent find of four specimens were from an area off Tamarapatnam at a depth of 100 metres. The rediscovery came after a gap of 120 years. The species got its name from its general appearance and posture. The crab rests on seafloor with its anterior end raised as if resting on the claws. So far, 11 species have been identified, including the three from India, they said.

The rediscoveries were, perhaps, due to the exploration of new grounds in the sea. More efforts in this direction may yield several other interesting specimens, said Dr. Vivekanandan. The rediscoveries also indicated the availability and status of these species in the Indian waters, he added.

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Printable version | Jan 22, 2022 2:34:36 AM | https://www.thehindu.com/sci-tech/energy-and-environment/Bat-fish-Razor-fishFrog-crab-rediscovered/article15507469.ece

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