Culture Fisheries

FRESHWATER AQUACULTURE

BRACKISHWATER AQUACULTURE

FRESHWATER AQUACULTURE

Spawning of Asian Catfish, Clarias batrachus

A breakthrough has been achieved in spawning Asian catfish, Clarias batrachus spontaneously. With the manipulation of hormone dose, latency period and brood stock feed, the fishes breed without stripping male and female and spawn spontaneously following hormone injection.

Seed Production of Gangetic Prawn, Macrobrachium gangeticum

The seed production trial of gangetic prawn, Macrobrachium gangeticum (Bate) synonym M. birmanicum choprai (Tiwari) were carried out in plastic pool following air-lift biofllter recirculatory system. The larvae were reared in brackishwater of 12-14 ppt salinity. The larvae passed through eleven larval stages with 16-18 molts. The first few post larvae occurred on 22nd day. A record production of 13,043 post larvae @ 43 PL/I was achieved with about 90% metamorphosis during 45 days of rearing cycle. 

Culture of Freshwater Prawn in Pens

The giant freshwater prawn, M. rosenbergii cultured in pens installed in beels for a period ranging from 92-95 days attained a size range of 135 rhm/38 g to 148 mm/ 57 g at a stocking density ranging from 21,000 to 25,000 nos./ha. A yield of 484 to 588 kg/ha was obtained in 92-95 days of culture. 

Evaluation of Dairy Emuents for Aquaculture Activity

To evaluate the potential of dairy effluents for aquaculture, a pen enclosure (0.011 ha) was constructed in the lagoon near the discharge point of dairy plant effluent. The pen was stocked with fingerling of Indian major and minor carps (catla, rohu, mrigal, silver carp and bata) at 5000 nos./ha. The fishes were reared for 6 months. All the species stocked exhibited very good growth indicating the potential of dairy effluent for aquaculture. The estimated productions of fish 'lfithin six months was 3.5 tonnes/ha. 

Development of Phosphatase Producing Bacterial Biofertilizers for Aquaculture

Bacterial isolates were collected and screened for phosphatase activity from both pond water and sediments. Out of the total 1079 bacterial isolates collected one hundred were found to be potential alkaline phosphatase enzyme producers. The study has indicated the possibility of using bacterial biofilter in fish farming activities in the country.

COLDWATER AQUACULTURE

Trout Culture at Champawat

Experiments were conducted to rear rainbow trout Onchorhynchus mykiss in the warmer agro-climatic conditions, where for nearly ten months the minimum water temperature remains above 10°C and the maximum ranges between 20-22°C, even the pH values always range between 8.0 to 8.2 and lower l~els of dissolved oxygen drop to 5.0 ppm. The water quality was uncongenial for trout farming. The water

quality was monitored and scientific package of practices for farming of rainbrow trout was adopted. The result was very encouraging and the .fishes attained the table size in the warmer agro-climatic condition of Champawat. These prized fishes were sold to the local people. This has opened up a great opportunity to local people to take up the trout farming which commands high price and has good demand in big metropolitan cities.
 

Cage Culture of Mahseer in Reservoir

Cage culture experiment for culture of mahseer has been conducted in the Walwan

reservoir. The nylon cages (2 to 5 mm and 2 to 15 mm) were stocked with commercially important mahseer at a depth of 2 metre in the reservoir. Encouraging results were obtained and after 150 days of culture the average net weight of Tor khudree increased from 35.2 g to 106 g and the average net weight of Tor putitora from 14.6 g to 52.4 g. The rate of survival of mahseer in these cages were approximately 98%.

BRACKISHWATER AQUACULTURE 

Polyculture of Brackishwater Finfishes and Shellfishes

A polyculture experiment with stocking density of 38,800 nos./ha (mullet 16,000; pearlspot 3,800; P indicus 12,000; P. monodon 12,000), was carried out in a 0.05 ha. perennial tide-fed pond at the Narakkal. A total quantity of78.2 kg offish and shrimp was harvested at the end of a culture duration of 6 months for fishes and 3-4 months for shrimps. The total production rate works out to 1,564 kg/ha. From an initial size of 25 mm/0.16 g for mullets, M. cephalus reached 250 mm/155 g and L. parsia 162 mm/36 g. E., suratensis attained 178 mm/134 g from an initial size of 58 mm/8 g. In the case of shrimp, PL20 reached a size of 152 mm/29 g for P. monodon and 101 mm/5 g for P. indicus. 
 

MARICULTURE

A breakthrough has been achieved in the seed production and larval rearing of sea cucumber Holothuria spinifera for the fIrst time in the hatchery by Tuticorin Centre of CMFRI, Cochin. The large scale ranching can augment their natural resource in our coastal waters thus increasing the production of Beche-de-mer and export quality prod~ct of the sea cucumber. 

Ornamentai Fish Breeding and Seed Production

The experiment has been taken to breed marine ornamental fish species Pomacentrus pavo (Peacock damselfish) in captivity. It was observed that the species spawns (in onshore FRP tanks with seawater) several times in a year laying about 1500-5000 eggs in each spawning. The larvae thrived well on bivalve eggs and, Artemia nauplii and mussel meat later. 

Tissue Culture in Pearl Oyster

Remarkable progress was achieved in tissue culture of abalone, pearl oyster and windowpane oyster. Achievements were made in the cryopreservation of excess cells produced during in vitro culture and their subculture.

Domestication of the Tiger Shrimp, Penaeus monodon

A major breakthrough in successful domestication of the tiger shrimp, Penaeus monodon has been achieved. The FI generation of hatchery produced and farm grown shrimps were induced to mature and spawn by artificial insemination and eyestalk ablation, giving rise to second generation population. Subsequently third and fourth generation population was produced from domesticated shrimp. This achievement in domestication is important in developing pathogen free and genetically improved stock through selective breeding programmes.