In February Dr Ravi RamaKrishna, Senior Scientist at the Fisheries Research Station in the West Godavari district of Andhra Pradesh, took a research team to visit the ‘fish bowl’ of India in the Kolleru Lake area of the State.
According to Peter Edwards writing for the Network of Aquaculture Centres in Asia Pacific (NACA), their intensive four day study tour involved visited fish farms and formal meetings with individual farmers in Mallavaram village in West Godavari district and Bhujabalapatnam village in Krishna district, cooperative fish farmers in Prathikollanka village, in West Godavari district, all by Kolleru Lake; to carp hatcheries and nurseries in the Kaikaluru area of Krishna district; and to fish farms and informal meetings with individual farmers towards Gudivada in Krishna district where a second phase of carp culture development has taken place.
Speaking about his experiences Peter Edwards said: "At the end of the tour I was only too pleased when asked to comment to a group of about a dozen farmers belonging to the Delta Fish Farmers Association. And I repeat here what I said to the farmers at the start of our final meeting, that four days was hardly sufficient time to fully appreciate the most impressive but complex aquaculture system I had been shown but that at the very least my comments should stimulate further debate about how to resolve some of the problems and how the system might evolve in the future."
Overview of the system
The technology of the current system of Indian major carp culture in Andhra Pradesh has been mainly developed by local farmers as described in the article by Dr. Nandeesha.
It is a simplified two-species system in which rohu is dominant with 80-90% of the fish biomass and with catla a very profitable 10-20%. Production may be described as semi-intensive and indirectly integrated. It is a ‘green water’ system with mainly local off-farm inputs: chicken manure (and chemical fertilizers); supplemented with farm-mixed de-oiled rice bran and oil cake.
Sustainable annual production is 3-4 tonnes/acre (7.5-10 tonnes/ha) although 5-6 tonnes/acre (12.5-15 tonnes/ha) have been achieved but at increased risk of fish mass mortality. Last year 5,000-6,000 farmers produced a total of 450,000 tonnes of fish from 60,000ha of ponds.
Farmers reported that they are experiencing problems, especially increasing cost of production, mainly due to rising cost of fertilizers and supplementary feed; and weather related fish mass mortality.
The main problem is the fall in dissolved oxygen (DO) in the rainy season in particular but also during cloudy weather in general and during cool season fog. Water quality problems also occur during the hot season from April to June when there is limited water availability, especially with high density culture, which may cause disease. The farmers also recognized the need for change, especially to farm new species for domestic and possibly export markets.