Shrimp Farming:

The technical improvements made in shrimp farming in many parts of the world paved the way to increase shrimp farming through aquaculture by adopting semi intensive systems of shrimp farming in the areas where environmental conditions are well suited. Tamil Nadu is endowed with rich natural resources such as coastal zones in the form of brackish water/estuaries for shrimp culture. At present shrimp aquaculture has been developed in 13 maritime districts of Tamil Nadu in about 5745.01 hectare. The giant tiger shrimp (P.monodon) and white leg shrimp (P. vannamei) are the most common species cultured in shrimp ponds. The farmers are encouraged to adopt semi intensive farming methods for sustainable aquaculture.

Sea Weed Farming

Sea weeds are simple plants grown in the shallow waters of the seas. These are popularly called "Sea Vegetables". There is a potential markets for the seaweeds. They can be easily cultivated with the help of floating rafts/monoline in the near shore areas. The Palk Bay and Gulf of Mannar area are abundant in seaweeds. The Gulf of Mannar area is well suited for Seaweed farming. The seaweeds are the only source for the production of phytochemicals such as agar, carrageenan and algin. Seaweeds are divided into Green, Brown, Red and Bluegreen algae based on the type of pigments, external and internal structures.

The dominant varieties of Seaweeds are :
Gracilaria edulis, Gelidiella acerosa, Sargassum, Turbinaria, Hypnea, Laurencia species.

Apart from these seaweeds Kaphaphycus alvarezii, which is an exotic species of seaweed is under culture in Palk Bay and Gulf of Mannar area.

There are two methods of cultivation of seaweeds.
• 1. By means of vegetative propagation.
• 2.Spores such as swarmers.

Mussel, Clam and Oyster Farming:

Mussel and Oysters are valuable shell fish resources of Tamil Nadu. The Green Mussel Perna viridis is predominant in Tamil Nadu. Open seas and estuarine areas free from strong wave action is ideal for Mussel culture. Clams are the most important among bivalve resources. Commercially exploited and cultivable clams are, Meretrix casta, M.Meretrix, Anadara granosa. Rich beds of clams exist in Pulicat lake, Vellar, Athankarai and Punnakayal estuaries along east coast. There is a great demand for bivalve meat.

Oysters inhabit littoral and shallow sub tidal areas. They occur in wide range of in eco-systems including the coral reefs, mangroves and rocky shores. The dominant species are Crassostrea madrasensis, C.gryphoides, C.rivularis. The different oyster farming methods are Rack and ren method, Rack and tray method.

Pearl Oyster Farming

The Pearl oyster (Pinctada sp.) occurs in the Gulf of Mannar and Palk Bay region. Six species of Pearl Oysters occur in Tamil Nadu. In the Gulf of Mannar, the pearl oysters occur in large numbers on the submerged rocky or hard substrata known as paars. In the Palk Bay, Pinctada fucata occurs sporadically on loose sandy substratum attached to submerged objects in littoral waters. Tuticorin Coast in Tamil Nadu is well suited for Pearl Oyster farming. Pear oysters can be cultured by Raft culture method, Rack culture and Long line culture. The natural pearl oysters harvested from Gulf of Mannar region is having high esteem due to its lustre.

Marine Fin Fish Culture

Cobia, Sea bass and Pompano are the most favoured candidate species for Fin fish farming. These fishes are highly priced marine food fishes having tender, tasty meat and good market potential. The enclosed bays, estuaries and shallow coastal waters are well suited for fish farming. The hatchery technology for seed production of sea bass has been standardized and seed production is not a constraint. The Sea bass can be grown in cages erected in backwaters.

Sea ranching

Sea ranching or artificial recruitment of aquatic organisms into their natural habitat for stock improvement or enhancing the production or for conservation of resources. Sea ranching involves mass release of juveniles of the selected species into the marine environment where, they can feed on natural prey and grows. The sea ranched stocks become recaptured and add to the biomass of the commercial fishery.

Artificial Reef

Artificial reefs are man-made or natural objects placed in selected areas of the marine environment to provide or improve solid and rough bottom habitat and thereby increase the productivity and harvestability of certain fish valuable to man. Artificial Reefs provide shelter, calm waters, influence water currents so that fish save energy while swimming against the current and attract smaller organisms which are vital sources of Food for different marine species.

An Artificial reef is an underwater artificial habitat for marine life. It helps in augmenting the productivity of the marine ecosystem. It increases the available area for food, shelter and breeding activities for fishes and other marine organisms. This also enhances the fish production through increased breeding activity and survival of young ones. Moreover, it act as the barrier for bottom trawling operations by mechanized boats in these areas and prevent the destruction of reefs which are the natural breeding habitats

Crabs and Lobsters Farming

Tamil Nadu is one of the leading states in India an on the export of marine products in which Lobster and Crab are considered to be having high export value. About 700 tonnes are harvested every year in which nearly 50% are of undersized juveniles varying from 50 grams to 250 grams per piece. Moulted crab otherwise called as water crab does not fetch good market value. Once it reaches to 250 grams size the price variation is double or even triple. Growth rate of crab in cages is encouraging with supplementary feed. Juvenile lobsters caught from the wild can well be grown to marketable size in cages by giving supplementary feed. Live export of lobsters and crabs fetch high market value.