Background:
The fisheries sector plays a vital role in the food, nutritional and livelihood security of people, especially in the rural regions of India. The estimated demand for fish by 2025 in the Indian domestic market would be about 16 million tonnes (MT) against the present production of 12.6 MT coming from inland (70%) and marine (30%) fisheries sectors (DAHDF, 2018). Aquaculture has emerged as the main driver of blue growth and a key component of food security which is central to the sustainable development goals. Around 70% of India’s fish production comes from inland waters, of which nearly 65% comes from aquaculture. Among the inland open water resources, reservoirs form an important source of fish production in India. The reservoirs are considered as ‘sleeping giants’ in view of their huge hidden fish production potential. Reservoirs contribute considerably to the inland fish production in India In India, the area under reservoir fisheries was estimated at about 3.15 million ha. Presently, the area under reservoir fisheries in the country has gone more than 3.42 million ha (19,386 numbers) with the addition of 16 reservoirs with total area of 0.27 million ha during 1989–2012. The average productivity from these reservoirs in India is nearly 30 Kg/ha against the production potential of 250 Kg/ha. These resources are evidently under unutilized, and this is not sufficient enough to match the ever-doubling rate of population demands. In general, mainly carp (IMC) is being cultured in most of the reservoirs. But, availability of seed is a major problem for development of reservoir fisheries. Studies suggest that fish fingerlings 70-100 mm and longer achieve better survival rates and good growth. However, the high cost of fingerlings resulted in efforts to source them locally, as this holds down the costs and mortality associated with transporting fingerlings. In many cases, the entire seed requirement cannot be met by local suppliers because they normally do not rear the seed to fingerling stage. The growout operations are often constrained by limited fish seed supply and a high demand for fingerlings. The reservoirs in India have substantially high fish production potential; however, the actual fish production from these water bodies remains low. The sustainable increase of fish production through enhancement approach, capacity building of stakeholders for fishery enhancement, reinforcing infrastructure and support services, strengthening institutional and governance instruments are the recommended policies for effective management of reservoir fisheries. A carp hatchery that can supply the requirement of healthy seed is the need of the hour to improve production in reservoir. For this purpose, rearing fry to fingerling at the reservoir site in cage units has been successfully demonstrated. Therefore, a new floating hatchery model has been developed for the production of spawns of carp and same spawns can be reared in cages till fingerlings.
Technology Details:
For enhancing fish production in reservoirs, it is imperative that the reservoirs are to be stocked with quality seed. Fingerlings of carp produced in land-based hatcheries at distant places experience stress during transportation from hatchery to reservoir. Further, the change in type and quality of water may reduce the survival rate of fingerlings when transported from hatcheries and stocked in reservoirs. Hence, it is a novel idea to design a floating hatchery unit consisting of jar hatchery, floating breeding and nursery units in the form of cages. This technology involves breeding, spawning, production of seed, and rearing of spawn to fingerling in reservoir itself. The floating hatchery unit for production of fingerlings in reservoir consists of the following components: I.Floating Breeding Cages Breeding unit consists of number of cages in which brooders are stocked. The brood stock management is done as per the standard protocol. Hapas with top-lid are placed within the cages for the purpose of breeding. Fully developed and healthy male and female brooders are selected and transferred to the hapas within the cage. Following the techniques of induced breeding, the brooders are sexually induced so that eggs are released. The brooders are removed from the hapas (6 hours after the release of eggs) and eggs are transferred to CIFE echo hatchery. The size and number of hapas depends upon the size of cage and targeted seed production capacity. II.Floating Hatchery The CIFE echo hatchery unit consisting of FRP jars is mounted on a floating platform with all requisite accessories. The eggs are collected manually from the hapas and shifted to FRP jars of the eco-hatchery unit. The hatchery is operated for about 72 to 84 hours for water hardening, hatching of eggs, and finally production of spawn (6 mm). Water can be directly drawn from the reservoir for hatching of eggs and subsequent production spawn. After obtaining required size, generally 6 mm, spawns shall be collected from floating hatchery and shifted to the Nursery unit. III.Floating Nursery Cages The nursery unit consists of number of floating cages. The number of floating nursery cages depends of size and the seed production capacity of hatchery. The size of cage mesh should be less than the size of spawn. Following the standard protocol, the spawn is reared in floating cages to produce fingerlings (about 5 cm). After checking the growth and health, the fingerlings are released in the reservoir. Since breeding, hatching, production of seed, spawn, and fingerings are done at one place in the same water, the chances of stress can be minimized and rate of survival can be increased. Further, the expenditure on seed transportation can be avoided.