Stock enhancement programme enters second phase

On Monday morning, a small group of fishermen set out to sea from the coastal village of Pozhiyoor, near here, on a mission they were not used to. Instead of their daily routine of bringing back fish caught from the sea, they were taking live fish out into the deep, to be released in the waters.

The fishermen were involved in a marine finfish stock enhancement programme launched by the Rajiv Gandhi Centre for Aquaculture (RGCA), the research wing of the Marine Products Export Development Authority (MPEDA). The 400 juvenile fish that were deposited in the sea on Monday belonged to Cobia, a commercially valuable species of finfish that has seen dwindling numbers. They were bred at the pilot scale hatchery set up by the RGCA at Pozhiyoor.

At seven months, the juvenile Cobia released into sea weighed only 400 gm each. “In just over a year, they could grow up to 15 kg,” says P. Anilkumar, project manager, RGCA. Also known as Lemon fish or Ling, the Cobia (Rachycentron canadrum) at full growth, achieved in two years, weighs around 35 kg, though a rare few are known to have reached 65 kg. The fish lives up to eight years.

Unlike most fish, the Cobia does not move around in shoals, making it difficult to be netted in large numbers. But, all over the world, they are a favourite of anglers, especially in the U.S. and Australia.

The few Cobia that are accidentally netted by local fishing vessels are either consumed by the boat owners and their families or sold to upmarket restaurants and well- heeled customers for a premium. Cobia is known for its firm, white and tasty flesh, making it a preferred choice for the sashimi, a Japanese seafood delicacy served raw and thinly sliced.

At the hatchery that was established in 2009, huge cement tanks equipped with pumps and biofilters are teeming with hundreds of juvenile Cobia distinguished by their grey upper body, and underbelly and black bands on the sides. Uniformed staff attend to the tanks and machinery throughout the day. The tanks are fed with water pumped from the sea through large underground pipes.

The hatchery depends on a raw stock of 35 lakh eggs collected from spawning fish. “We trained the local fishermen to capture Cobia live from the sea using hook and line,” explains Mr. Anilkumar.

The brood stock division in the hatchery currently features a couple of Cobia weighing around 15 kg each.

The Cobia start breeding at about 18 months of growth. “A spawning female produces millions of eggs. But very few survive at sea. By producing them in large numbers at the hatchery and releasing them into the sea as juveniles and sub adults, we ensure their survival and proliferation”, says Mr. Anilkumar.

The RGCA has plans to provide electronic tags for the Cobia to track them at sea and 0identify their migratory route.

Kulathur panchayat president Pozhiyoor Johnson, district panchyat member Ushakumari and Vicar of the Kollengode church, Father Shajan Jose were among those who witnessed the loading of fish onto the boat at Pozhiyoor beach on Monday.

The technology for production of Cobia seed and breeding the fish in captivity was developed by the RGCA to restore the natural stock. The sea ranching (release of artificially bred fish) programme, inaugurated by Chief Minister Oommen Chandy last month, is expected to enhance the production of Cobia in the area around Vizhinjam from 500 to 2,000 tonnes over the next three to four years. The RGCA has drawn up plans to produce an additional 3,000 tonnes through cage farming at sea.