Introduction

Jammu and Kashmir provides a palatable habitat for a variety of fishes due to large number of water resources and agro-climatic conditions which provides the way for the successful culture and development of fisheries sector in the state. There are about 1,248 water bodies in Jammu and Kashmir State having total spread area of approximately 57,000 hectares out of which about 24000 hectares are in the shape of reservoirs, lakes and marshy areas and 23000 hectares in the shape of rivers (Anayat and Arjamand, 2013). These water bodies provide a pleasant climate for the growth of large number of plants and animals. Various species of fishes including both warm water and cold water are found in the water bodies of the state. Trout, Schizothoracines, Indian major carps and Chinese carps are the fish species which are dominating there. In Kashmir most of the fishes are cold water in nature and have adapted and thrived well to the climatic conditions of Kashmir. Fishes belonging to the families Salmonidae, Cyprinodontidae, Sisoridae, Siluridae, Cyprinidae and Cobitidae are found in the water bodies of Kashmir. Due to congenial conditions for the development and sustenance of different varieties of fishes, the production is showing an increasing trend in absolute terms. The fish catch which was 18,467 tonnes in 2000-2001 has reached to 19,300 tonnes in 2009-2010 and it crossed 21,060 in 2018-19 by attaining a production of 21.06 thousand tonnes. The Kashmir province is the leading producer of fish in the state and contributes about 80% to the total fish production (Qayoom and Bhat, 2015). This means that about 87% of fish was from the Kashmir Division (DOF J&K, 2011). Among all the fish species, trout being an exotic fish species has thrived well in Kashmir as the climate, topography and environment conditions are well suited for breeding, rearing, production and marketing of trout fishes. The production of trout has increased from 90 tonnes during 2002-03 to 155 tonnes during 2010-11 and presently it is more than 450 tonnes in 2016-17 (Annual Report of J&K Fisheries Department). The rivers, lakes, streams and springs of the state provide the healthy environment for trout fishes as they are fed by the snow-fed and glacier-fed waters providing the necessary and suitable water quality parameters for the growth of the fish. In Kashmir two important and popular species of trout are Brown trout (Salmo trutta fario), and Rainbow trout (Oncorhynchus mykiss). Among the two species, rainbow trout is dominating in most culture based systems because of easy availability of both seed and feed, also its demand is very high among the fish eaters of the valley due to its taste and quality of the meat. Commercial culture of trout is well established in Europe and United States of America and dates back over 400 years in Europe and over 150 years in USA (Hinshaw, 1990). Beside rainbow trout which is the dominant species and cultured widely other species like brook trout (Salvelinus fontinalis) and brown trout are also farmed (Hinshaw et al., 1990). The largest producer of rainbow trout in the world is Chile followed by Norway, Iran, Italy and France (FAO, 2013). To introduce trout in the water bodies of India, the first attempt was made by Sir Frances Day in 1863 when he introduced eyed eggs and fry of brown trout in Nilgiri hills of India, but did not get success. The state of Jammu and Kashmir has a total of 0.3 lakh hectares area of inland water bodies in the form of 27781 km of rivers and canals, 0.7 lakh hectares of reservoirs, 0.17 lakh hectares of tanks and ponds, and 0.06 lakh hectares of flood plain lakes/derelict waters (Ayyappan et.al., 2011). The Kashmir province of the state has 486 km of rivers, 447 km of stream and about 157 sq. km of lakes (Sodhi et al., 2013). These rivers and streams are suitable for trout farming in the state due to the nature of environment and the quality of water. In addition to rivers and streams, trout can be cultured in raceways taking water from rivers, streams and even lakes. Realizing the potential of trout farming, Government of Jammu and Kashmir and Government of India have started a number of schemes to promote trout farming in the state. In Kashmir the history of introduction of Trout started the first batch of Trout ova of 10,000 eggs arrived from U.K. in 1899 with the courtesy of Duke of Bedford, to whom the Kashmir Maharaja presented an excellent Kashmir Stag trophy through Sir Adelbert Talbot, British Resident at Srinagar. Unfortunately this first batch of trout perished along the way to Kashmir due to the lack of suitable transport facilities. The second attempt was taken by Mr. F.J. Mitchell and he succeeded in introducing eyed eggs of brown trout in Harwan hatchery of Jammu and Kashmir in 1990. With the help and assistance from European Economic Community (EEC), culture of Rainbow trout was successfully done in Jammu and Kashmir and Himachal Pradesh states (Ayyappan et al., 2011). In 1900 F.J Mitchel transferred 1800 fry from Scotland, out of this 800 fry were reared in the premises of a private carpet factory owner (Mr. Michel) in Baghi Dilawar Khan in the heart of city near Khank-e-Moulla and 1000 fry were transferred to Panzagam Dachigam (Harwan) about 24km from Srinagar.

Production trends

The trout and salmon are the world’s second most traded fish species in terms of value accounting 14 percent of global trade following shrimp which accounts 15 percent of the total. Salmon, trout and other diadromous fishes accounts for 6.4 percent (4 million tons) of the total global aquaculture production. Global salmon and trout production reached 1,112,988 tonnes in the year 2011. Chile is world leading rainbow trout producer followed by Norway, Iran, Italy and France. In the European Union, the main producer is Italy with 38,000 tonnes followed by France and Denmark with around 33,000 tonnes (FAO, 2013). According to FAO about 8.14 lakh tons of rainbow trout were produced in aquaculture in 2014. More than 206 species belong to the family of Salmonidae, with salmon (Salmo salar) and rainbow trout being two of the world´s most important fish species for consumption (Huber et al., 2004).

In India despite a long history of introduction and well flourished aquaculture practices trout farming is not widely practiced on commercial scale. In India, the mountainous regions in the Himalayan states are endowed with copious amounts of highly oxygenated pristine freshwater which is highly suitable for rainbow trout culture. Thus trout culture in India is restricted to the upper Himalayan region, besides this Western Ghats also provide a favourable climatic conditions for the culture of this fish. After its introduction in India during early 20th century, rainbow trout is becoming a source of livelihood and food security to the hill population. The fish is distributed across the states of Jammu and Kashmir, Himachal Pradesh, Sikkim, Arunachal Pradesh and Uttarakhand. With about 62 government trout farms and 660 private trout production units, the annual production in India reached nearly 842 tons (DCFR, 2017). Besides there are 32 government affiliated rainbow trout hatcheries with an estimated production capacity of 13 million eyed ova and 3 well equipped feed mills with an installed capacity of nearly 10 tons per day. The ICAR-Directorate of Coldwater Fisheries Research is undertaking the research and development efforts to expand and intensify rainbow trout production, in partnership with the concerned state fisheries departments.

In Jammu and Kashmir, trout fisheries received a major thrust during the last two decades with the establishment of Mother Trout Fish Farming Project at Kokernag under European Union Assistance in 1984. The Department has another Trout Hatchery at Laribal where quality Trout seed of Brown Trout and Rainbow Trout is being produced. The use of modern technology in breeding and rearing of fish has ensured a better survival at different stages of the fish. Besides this, the Department established trout feed mill with highly equipped facilities imported from Holland in 2012 and it produces quality trout feed to achieve better conversion ratio and healthy stock. Both of these projects have the capacity to produce more than 132 lakh eggs per year. The state Department has established a network of more than 42 trout rearing centre in public sector and 513 rearing units in private sector across the State and the number is increasing day by day. (DoF J&K, 2019)

The department has established various hatcheries in different districts of the state and is enlisted below:

Morphology and habitat

Rainbow trout belongs to the family Salmonidae with elongated, fusiform body having vertebrae of 60-66 in number. The fish possesses 3-4 dorsal spines, 10-12 dorsal soft rays, 3-4 anal spines, 8-12 anal soft rays, 19 caudal rays. As the fish is carnivorous in habitat, it possesses an adipose fin with a black edge. In rainbow trout the body is blue to olive green in colour and possesses some pink bands along the lateral line

Rainbow trout is a freshwater, fast growing fish and tolerates a wide range of environmental conditions. The species can withstand wide ranges of temperatures (0-27 °C), but spawning and growth occurs in a narrower range (9-14 °C). However the optimum water temperature for rainbow trout culture is 15 to 20 °C, thus rainbow trout is compatible with most conditions and climates (Adeli and Baghaei, 2013; Bergheim, 2014). This is one of the possible reasons that trout farming was introduced in many countries during the last decades and is now practiced considerably in 82 countries all over the world. Thus temperature and food availability also influence growth and maturation, causing age at maturity to vary usually from 3-4 years.

For the successful culture of trout, water should be pure, free from pollutants, transparent, free from dirt and suspended particles. For commercial trout production, the site must have a year-round supply of high quality water (1 l/min/kg of trout without aeration or 5 l/sec/tonne of trout with aeration), that meets a number of criteria:

Reproductive Biology

Sexes are separate and can be easily distinguished during the breeding season. The lower jaw of the male is turned up in the form of hooked beak shape and in females such modification is not found. Also ripe females possess genital papilla but the same is absent in males. Again if the body of the female is pressed, the eggs will flow out however on pressing the male the milt flow.

Trout attain maturity at the end of second year. The male releases good quality milt between the age group of two and four years while as in females good quality eggs are obtained in the age group of three and six years. With the increase in age, yield of eggs also increases but part of their descendants may be sterile (Huet, 1986).

Rainbow trout spawning occurs during the spring from January to May where as brown trout and brook trout spawn from October to January in USA/Europe. In India the brown trout and brook trout breeds during December to January while as rainbow trout breeds during February and March except in Avalanche (Tamil Nadu), where it breeds from September to February. Fecundity of trout is very low and it ranges from 1,500- 2,000 eggs/kg of body weight and the eggs are relatively large with a diameter of 3-7 mm.

Usually rainbow trout spawns once in a year during spring season from January to May. However by making some adjustments like selective breeding and in photoperiod, some strains have been developed that can mature earlier and spawn all year round.

In case of culture systems, trout do not spawn naturally; thus juveniles must be obtained either by artificial spawning in a hatchery or by collecting eggs from wild stocks. In the wild, adult trout feed on aquatic and terrestrial insects, molluscs, crustaceans, fish eggs, minnows and other small fishes. The most important food for trout is freshwater shrimp which contains carotenoid pigments which are responsible for the orange-pink color in the flesh. To produce such coloration in fish meat, various synthetic pigments like astaxanthin and canthaxanthin are used in various aqua feeds.

Culture

In case of aquaculture systems trout will not spawn naturally, hence eggs are taken artificially from the high quality brood fish when they are fully ripe. Males of more than two years old and females three years older are usually selected as the yield and quality of such fishes is good. The number of brood stock required is dependent on the number of fry or fingerlings required to meet the production schedule of the farm and it also depends on the survival rate of the different life stages and fecundity of the brood stock females. Generally the sex ratio of 1:3 is preferred that is one male to three females is deemed desirable. As brood stock maintenance is costly and labor intensive, so most of the farms purchase eyed eggs from other sources; these should be 'certified disease free'. Fishes which have attained age of more than two years can be selected for brood stock.

Egg and milt collection

The eggs from female and milt from male are collected by stripping method that is by applying gentle pressure on both the sides of the belly from front to back. The commonly used methods for taking egg from fishes are;

Hand stripping without incision (one man method and two man method):

In one man method single person takes the eggs from the fish by holding the fish with ventral side down above the pan by one hand and by other hand a gentle pressure is applied and the eggs come out. In case of two man method one person holds the fish and other person perform the stripping operation.

Hand stripping after incision:

In this method an incision is made in the vent region to facilitate easy flow.

Australian Method (Worton`s Method):

In this method a hypodermic needle is inserted into the fish and air is pumped in, using a bicycle pump connected with the needle. Air is pumped inside the abdominal cavity of fish and the eggs get expelled through the vent.

Swedish method:

In this method female is placed inside a double walled rubber sac with the provision to hold the fish closely. Water is pumped into the sac at an appropriate pressure and it exerts the pressure on fish resulting in release of the eggs.

Males are stripped in the same way as females, collecting milt in a bowl, avoiding water and urine contamination. After collecting the eggs and milt, both are mixed and fertilized either by using water (wet method) or without water (dry method). The dry method of fertilization without admixture of water is the most common approach. Fertilized eggs can be transported after 20 minutes, and up to 48 hours after fertilization, but then not until the eyed stage. A technique that has been developed to improve production output is the use of monosex culture of females, or triploids, all-female broodstock to produce all- female progeny that grow faster. Triploidy is induced by exposing the eggs to pressure or heat whilst monosex are produced by fertilizing normal female eggs (XX chromosomes) with milt from sex-reversed, masculinised females (XXX chromosomes).

Diseases and control measures

A variety of diseases and parasites affect rainbow trout in aquaculture, some are summarized in the table below. For the successful culture, prevention is the most important measure; good hatchery sanitation, good quality seed and feed disinfecting equipments etc reduces the exposure of vulnerable fish to disease-causing agents. In some cases antibiotics and other pharmaceuticals have been used in treatment but their inclusion in this table does not imply an FAO recommendation.

Management and constraints

The success of the rainbow trout culture depends on utilization of proper and best management practices. It starts from the selection of suitable site for the farm to the selection of healthy brooders, good quality seed, proper feeding, fresh, clear and pristine water quality, stocking density, proper marketing channels etc. The effluents from the trout farms should be treated properly before diverting it to the natural water bodies. Impacts from flow-through systems are largely due to disease treatment chemicals, uneaten feed and fish excreta, which can alter water downstream of the farm. Elevated nutrients reduce water quality (increasing biological oxygen demand, reducing dissolved oxygen and increasing turbidity) and increase the growth of algae and aquatic plants. Output restrictions require farms to have settling areas to remove solid wastes and the residual feed in water to prevent water deterioration and disease outbreaks. The government started privatizing trout farming with the assistance from the central government under RKVY scheme since 2009-10. Under this scheme, the state fisheries department provides 80% subsidy and rest 20% was born by the beneficiary. Study showed that there are weak linkages between farmer and credit institution. There is need to develop strong linkages between the key actors which will help to improve trout value chain in Kashmir valley.

Price of the trout feed is the major constraint faced by the farmers during the culture period. There are only two feed mills producing trout feed in the entire valley and as trout culture totally dependent on artificial feed thus cost of feed accounts major share in trout culture. The second most important constraint is price of input seed and the trout seed price of Rs 5-10/piece is very high in comparison to carp seed. As reported by Tuburan-Bombeo et al. 2001, Ele et al 2012 and Gawa et al 2017 the feed and seed are found to be the two most important factors in trout production and it adsorbs almost 70 percent of cost of production. Third most important constraint faced by the farmers is transportation of seed from hatchery to farm as it needs some technical knowledge as fingerlings require high oxygen. Other constraints faced by trout farmers were continuous availability of clear and continuous water, contamination of water during rainy season, high cost of inputs, high rate of mortality, lack of crop insurance etc.

Besides these, negative effect of effluent from intensive and semi intensive farms on the environment, deteriorating water quality, eutrophication of the water bodies which receive nutrient rich farm waste, reducing dissolved oxygen thus increasing biological oxygen demand (BOD) and chemical oxygen demand (COD) are the other constraints faced by trout culturists (Aglagarswamy, 1995).

Conclusion

Trout is a high value fish which needs unique environmental conditions and it is observed that trout has very well adapted to the environmental conditions of Kashmir. But there are some constraints faced by the farmers and other people who want to start this business like lack of adequate seed supply and cost of feed. There is a need to privatize the trout feed and seed production sectors as has been done in the case of culture which showed promising results. Besides, the state is having a lot of natural resources in the forms of lakes, rivers and canals, reservoirs, springs, tanks and ponds and floodplain areas. Thus there is an ample scope for increasing the production and productivity of trout in Kashmir. This can be achieved by increasing the number of hatcheries to provide enough seeds for stocking in various public and private farms and open water bodies. Besides this some other interventions like cross breeding of brooders from various geographical locations to reduce inbreeding depression.

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