Extensive fishing off the Coromandel coast could be forcing the great seahorse to migrate laboriously toward Odisha.
Fishing is less intense in the Bay of Bengal off the Odisha coastline. But the shallow coastal ecosystem of the eastern Indian State may not be the new comfort zone for the fish with a horse-like head, a study published in the latest issue of the Journal of Threatened Taxa said.
The study was based on a specimen of a juvenile great seahorse, or Hippocampus kelloggi, caught in a ring net and collected from the Ariyapalli fish landing centre in Odisha’s Ganjam district. The authors of the study are Anil Kumar Behera and Biswajit Mahari of Berhampur University’s Department of Marine Sciences, and Amrit Kumar Mishra of Bombay Natural History Society’s Department of Marine Conservation.
There are 46 species of seahorses reported worldwide. The coastal ecosystems of India house nine out of 12 species found in the Indo-Pacific, one of the hotspots of seahorse populations that are distributed across diverse ecosystems such as seagrass, mangroves, macroalgal beds, and coral reefs.
These nine species are distributed along the coasts of eight States and five Union Territories from Gujarat to Odisha, apart from Lakshadweep and the Andaman and Nicobar Islands.
The population of the great seahorse, which is among the eight species tagged ‘vulnerable’, is declining due to its overexploitation for traditional Chinese medicines and as ornamental fish, combined with general destructive fishing and fisheries bycatch, the study said.
“Despite the ban on fishing and trading activities on seahorses from 2001, clandestine fishing and trading still take place in India. This creates immense pressure on the seahorse populations that have a high dependency on local habitats to maintain their extensive and long-life history traits,” it said.
Seahorses are poor swimmers but migrate by rafting -- clinging to floating substrata such as macroalgae or plastic debris for dispersal by ocean currents – to new habitats for successful maintenance of their population.
However, the 1,300 km northward migration of the great seahorse from Palk Bay and the Gulf of Mannar to Odisha is likely a response to extensive fishing activities around the southern coast of India. The species is abundant off the Coromandel coast (Andhra Pradesh and Tamil Nadu) but is under extensive fishing pressure, with 13 million individuals caught per year, the study said.
Better conservation needed
“This calls for increased monitoring of the coastal ecosystems of India on the east coast for better conservation and management of the remaining seahorse populations,” it advised.
But the great seahorse is not migrating in large numbers, as the Odisha coast does not have coral reefs or seagrass meadows that the species can call home, except within the Chilika region, Mr. Mishra said.
“The intensity of fishing is much lower compared to the Gulf of Mannar and the Palk Bay region. So, even if they migrate northwards, they would not have a suitable habitat, unless the fishing nets that catch them are banned or the fishing practices such as trawling are stopped,” he told The Hindu.