Strategy of fish seed production in India

In tropical countries like India, climatic conditions vary in different parts, as a result the breeding of fast growing species such as Catla and silver carps poses considerable problems due to erratic or late monsoon or prolonged dry spell. Hence it is not possible to meet the fish seed requirement of the country. Therefore: to meet the future requirement and to over-come the environmental conditions a Modern carp Hatchery CIFE D-81 was designed. The system provides optimum temperature, silt free clean, cool, highly oxygenated water, low current and continuous removal of metabolites. It has been successfully demonstrated at Rawatbhata (Rajasthan), Badkhal (Haryana), Badbhada (M.P), Guntur and East Godavari District (A.P). Recently a Modern Carp Hatchery was installed in a semi-arid zone, Damdama (Haryana), during 1984, where it has produced record 1.88 crores of fish seed and worked successfully.

Control of crabs and snakes in freshwater fish seed farms

A design has been developed to adopt in freshwater fish seed farms for controlling crabs and snakes. The method is convenient and effective. It prevents the entry of crabs and snakes into the ponds.

Available lysine in canned fish

Otolithus argenteus was canned in brine by heat processing at two different steam pressures either at 0.70 kg/cm super(2) or 1.05 kg/cm super(2) for 25 minutes. The nutritive value of canned fish as evaluated by the total nitrogen and available lysine did not alter much either during heat processing or during storage over a period of nine months at 28 degree plus or minus 5 degree C.

A note on mass mortality of fish in Shivpur Talab (Madhya Pradesh)

Shivpur Talab is a perennial tank in Hoshangabad district (Madhya Pradesh) having a maximum water spread of 4 ha. It is rainfed and also draws water from a close by Tawa canal. On 21st May 1985 heavy mortality of fish was noticed in the tank. The talab was stocked with fingerlings Catla catla, Cyprinus carpio and Labeo rohita approximately one year before the date of mortality. Scientific investigation revealed that mass mortality of fish occurred due to reduction in water area of the tank which in turn brought out oxygen depletion. The paper deals with the factors which brought about mass mortality of fish in Shivpur Talab.

Studies on the feeding biology of an airbreathing fish Heteropneustes fossilis (Bloch)

The food and feeding habits of an air-breathing fish, Heteropneustes fossilis were studied from an eutrophic lake, Hussainsagar, Hyderabad, (Andhra Pradesh, India), during 1981-1983. The major preferred items of food were insect larvae, insects, ostracods, plant material and gastropods. Due to the mixed feeding habits of both plant and animal matter, this species is considered as an omnivorous feeder. Bryozoans were recorded for the first time in the diet of H. fossilis.

Fish seed production under controlled hatchery system: a cottage industry

The fish seed production in recent times has emerged as a cottage industry, with the development of controlled hatchery system. Two units of six buckets of vertical hatchery system i.e. Modern Carp Hatchery CIFE D-81 were installed in a private fish farm. 130.25 lakh spawn of Indian Major Carp (Cyprinidae) was produced during the 1988 season, with an average survival rate of 70%. The results support the viability of technology especially for the economically weaker section.

Studies on fish epidemics from Assam

Investigations conducted since July 1988 on ulcerative fish epidemics in Assam, India, indicated that mainly four species of fishes belonging to the genera Puntius, Channa, Macrognathus and Mystus were widely affected by the disease. Results indicated that outbreak of the disease may not be due to organic pollution of water or radioactive and heavy-metallic contamination. Bacterial culture revealed colonies of Escherichia coli and Pseudomonas aeruginosa in the surface muscular lesions and gill tissues while preliminary electron microscopic studies indicated the presence of viruses in the muscles and gills of diseased fishes.

Acute effect of sumithion on certain blood parameters and mortality rate of fish, Heteropneustes fossilis (Bloch)

The acute toxic effect of the toxicant sumithion (50% E.C.) on mortality rate (after 24, 48, 72, and 96 h), total RBC count and haemoglobin content (after 48 and 72 h) on Heteropneustes fossilis was investigated at four concentrations (9.7, 10.7 and 11.1 ppm). The sumithion treated fishes showed lower RBC and Hb levels than the untreated ones. A gradual decrease in the total RBC counts and Hb contents was recorded with increasing concentration of toxicant after 72 h but the blood showed fluctuating values after 48 h of treatment.

Rice-fish culture: status and potential for increased production in the southwestern states of India

The scope of increasing production through rice-fish integration, suitable for coastal districts of Kerala, Karnataka, Goa and Maharashtra, is reviewed. The method of adopting the lowlying freshwater rice fields to raise 2 rice crops along with 4-species fish culture, followed by a third non-cereal summer crop in a year, is discussed. A calendar of operation and economics of the system are presented.

Quality problems in fish processing

Various problems associated with the quality of the fishery products like spoilage, discolouration, microbiological problems, etc., are outlined. The reasons and remedial measures are discussed. The importance of proper handling, processing and hygiene is stressed.

Laboratory reared eggs and larval stages of the clupeid fish, Opisthopterus tardoore (Cuvier)

The early embryonic and larval stages of Opisthopterus tardoore are described and discussed. The developing 3 eggs of stages up to 21hrs after collection and larvae up to 118hrs after hatching were reared in the laboratory. Seasonal occurrence of the eggs in the Vellar estuary, Porto Novo (lat. 11 29'N; 79 degree 46'E) was recorded for a period of 2 years (Nov. 1977 to Oct. 1979). Variation in myotomic counts in the larvae is critically reviewed with earlier works.

Comparative toxicity of some detergents on an estuarine fish, Ambassis commersonii

The comparative toxicity was evaluated using four detergents, viz, linear alkylbenzene sulfonate (LAS), branched alkylbenzene sulfonate (BAS), sodium sulfonate (SS) and alfa-olefin sulfonate (AOS) on an estuarine fish, Ambassis commersonii, abundant in Kali estuarine system. Standard toxicity bioassay method was followed as per APHA (1980). AOS concentration in "Mega" soap was determined by the standard MBAS method described in APHA (1980). The results indicate that LAS was the most toxic detergent to fish relative to the other types and the other of toxicity was LAS > AOS > SS > BAS. A significant correlation was seen between observed and calculated mortalities for all the detergents. Some behavioural responses of fishes to all detergents were also observed.

Fish catch composition in relation to some hydrographic observations along the Bombay Ratnagiri coast

Hydrographic parameters in relation to fish catch composition within the depth range of 30 m to 97 m at 15 different stations off the Bombay to Ratnagiri coast were studied from onboard the vessel M.V. Saraswathi, a 36.5 meter deepsea going research-cum-training vessel during her 58th cruise from the 17th to the 27th December 1986. The study indicates the abundance of Trichiurus sp, Priacanthus sp and Arius sp. Fluctuations in the zooplankton biomass and faunistic composition in the area are examined in relation to some important hydrographic parameters.

Impact of the exotic fish, Oreochromis mossambicus, on the indigenous fishery of Powai Lake, Bombay

Fishes impart the most profound influence on the floral-faunistic characteristics of an aquatic ecosystem. Oreochromis mossambicus, an exotic fish accidentally introduced in the Powai lake, India, caused considerable changes in the growth pattern of Indian major carps, ultimately reducing the productive potential of the lake from 33.0 to 11.9 kh/ha. Powai lake is used exclusively for angling for sport. The angling pressure based on the "creel census" from 1955 to 1976 gives a clear picture of the trends in the fishery therein. A considerable decline, ranging from 171 to 400% in the average weight of Indian major carps was recorded.

Management of waterlogged areas, island and coastal saline soils using fish based mixed farming system

Problems in India regarding the management of various coastal saline soil and waterlogged environments are discussed in detail, considering in particular the potential application of mixed fish farming systems. Various operational and cost requirements of such systems are examined.