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Impact of Exotic Aquatic Species in Indian Waters H.P.C. SHETTY M.C. NANDEESHA College of Fisheries University of Agricultural Sciences Mangalore - 575002 A.G. JHINGRAN Central Inland Capture Fisheries Research Institute Barrackpore - 743101 West Bengal Shetty, H.P.C., M.C. Nandeesha and A.G. Thingran. 1989. Impact of exotic aquatic species in Indian waters, p. 45-55. In S.S. Dc Silva (ed.) Exotic Aquatic Organisms in Asia. Proceedings of the Workshop on Introduction of Exotic Aquatic Organisms in Asia. Asian Fish. Soc. Spec. Pubi. 3, 154 p. Asian Fisheries Society, Manila, Philippines. A number of food, game, larvicidal and ornamental fishes have been introduced into India since over a centusy. Of more than 300 exotic species introduced into the country, the majority are aquarium fishes. Among the food fishes the majority belong to the cyprinid group, the prominent among which are the common, silver and grass carps. Grass carp has proved useful both as a culture fish and as an effective biological agent for weed control. Accidental entry of silver carp into Gobindasagar reservoir has resulted in decline in the production of Indian major carps, as well as in total catch. The bighead, introduced recently through private trade is also causing serious concern. The Java tilapia, Oreochromis mossambicus, is considered a pest, though it continues to form a commercial fishery in some reservoirs and is also cultured in some parts of the country. Some of the salmonids introduced into the country have peiformed well and are gaining increasing popularity. Among the molluscs, the giant African snail holds promise for export, while posing a pest problem in certain regions. The accidentally introduced fouling bivalve Mytilopsis sallei is causing grave concern. Water hyacinth and Salvinia are the two exotic plants which have become a major menace in the fishery waters of the country. India, with its very extensive freshwater resources, has a wide spectrum of native aquatic fauna and flora. All the same, there have been introductions of several exotic aquatic species into the country since over a century. Early introductions mainly consisted of game fish, food fish of minor importance and larvicidal fish. In the post-independence era, a number of cultivable fishes have been introduced with the objective of increasing production from aquaculture. Apart from these, innumerable ornamental fishes have also been introduced into the country at different times. Though these introductions have helped to widen the species spectrum, their impact on indigenous icthyofauna in capture and culture fisheries has not been properly evaluated until now, eventhough it has been realized that some of the introduced fishes have adversely affected the indigenous species. Apart from fishes, a large number of aquatic plants have also been introduced into the country and a few of them also have severely damaged the fishery waters. Therefore, an assessment of the present status of such introductions is urgently needed. 45
46 Present Status of Exotics in India The major exotic introductions and their impact on the indigenous fauna in ,eneral and aquaculture in particular, are dealt with in the following section and are listed in Tabls 1 and 2. Food Fishes Trout The areas around the Himalayas in the north and the peninsular hilly regions in the south are temperate in climate, and suitable for the culture of cold water fish. The first attempt to introduce trout as a sport fish was made in 1863 by Francis Day in Nilgiris of peninsular India. However, rainbow trout (Salmo gairdneri) from Sri Lanka, Germany and New Zealand were the first salmonids to be established in many streams of Nilgiris. The submergence of a number of trout streams in the newly formed reservoirs and increasing pollution of the remaining s'ieams have led to a sharp decline in the trout fishery in the post-independence era. In an attempt to improve the trout fishery efforts have been made to introduce some new species such as brown trout and tiger trout (hybrid between brown trout and eastern brook trout (Salvelinusfontinalis) and sockeye salmon (Onchorhyncus nerka). Among the various species of trout introduced in Nilgiris so far, only the rainbow trout has survived under the existing climatic conditions. It appears that trout culture is no longer an economical proposition in NiIgiris region due to pollution of streams and serious disease problems (Sreenivasan et al. 1988). Similarly, in the Himalayan region, introduction of trouts commenced after nearly three decades of their introduction in the Nilgiris region. Of all the introductions into the Himalayan region only brown trout provides a fishery on a commercial scale in streams (Sehgal 1988). Though attempts are being continued to establish trout populations in the cold regions of northern and eastern India, the success is not always commensurate with the efforts, largely due to stocking of undersized fish and the increasing pollution of streams. However, in some high altitude lakes, like Deodital of Central Himalayas, the brown trout has established itself and is breeding naturally (John and Prasad 1988). According to Jhingran and Sehgal (1978), altogether 719 km of trout streams are available in the country, in addition to over 4000 ha of natural and man-made lakes with trout ?opulations. The analysis of creel census data provided by the anglers has revealed that the brown trout catches were around 608-640 g/rod/hr/km fishable length in the Himalayan region in 1971, while in the Nilgiris in the south, the catch was about 457 g/rod/hr/km during 1966-68 (Jhingran and Sehgal 1978). As compared to some other introduced fish species, the trout have remained noncontroversial because of their restricted distribution and lack of indigenous cold water sport fishes. The populations of Schizothorax spp. do not appear to have been adversely affected by the presence of trout. Golden carp The crucian carp or golden carp (Carassius carassius) was introduced into India in 1874 in the Ooty lake at Nilgiris. The fish thrived well in Nilgiri waters and formed an important fishery
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Exotic Aquatic Organisms in Asia /
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Exotic Aquatic Organisms in Asia Pr
Page 5 and 6: The Introduction of Exotic Aquatic
Page 7 and 8: Introduction This special publicati
Page 9 and 10: help to promote national awareness
Page 11 and 12: Conditions in Europe and North Amer
Page 13 and 14: 2 taken as the basis for the introd
Page 15 and 16: 4 with respect to other introductio
Page 17 and 18: 6 Costa-Pierce, B. 1988. Study miss
Page 19 and 20: 8 extinction of the endemic rainbow
Page 21 and 22: 10 bottom substrates by European ca
Page 23 and 24: 12 Arthington 1988; Lloyd 1987); G.
Page 25 and 26: 14 Apparent Extinction of the Lake
Page 27 and 28: 16 successful and more often than n
Page 29 and 30: 18 Reznick, D. 1981. 'Grandfather E
Page 31 and 32: 20 -24° 4' 4 - I- .300 Cl) '1 S 36
Page 33 and 34: 22 The terminology associated with
Page 35 and 36: 24 Table 2. Translocations of indig
Page 37 and 38: 26 MELANOTAENIIDAE Melanotaenia spl
Page 39 and 40: 28 ELEOTRIDAE - GUDGEONS Hypseleotr
Page 41 and 42: 30 POECILIIDAE - LIVEBEARERS Gambus
Page 43 and 44: 32 References Allen, G.R. 1982. A F
Page 45 and 46: 34 Robinson, S.E. 1982. The ecology
Page 47 and 48: 36 1973. It has been cultured in so
Page 49 and 50: 38 northern Japan, settled off Dali
Page 51 and 52: 40 Table 1. The exotic aquatic food
Page 53 and 54: 42 Table 2. The preliminary list of
Page 58 and 59: Table 1. Salinonids introduced into
Page 60 and 61: Grass carp The grass carp, Ctenopha
Page 62 and 63: Table 4. Total catch and tilapia yi
Page 64 and 65: Salvinia molesta, a floating fern o
Page 66: Joy, PJ., K.R. Sathesan and D. Jose
Page 69 and 70: 58 Table 1. Introduced aquatic spec
Page 71 and 72: 60 The 1940s The Inland Fisheries D
Page 73 and 74: 62 Indonesia includes three differe
Page 75 and 76: 64 information on the status of fau
Page 77 and 78: 66 Table 1. List of exotic aquatic
Page 79 and 80: 68 Table 1. Continued Taxonomic Sta
Page 81 and 82: 70 From this historical review, it
Page 83 and 84: 72 what they perceived as economica
Page 85 and 86: 74 Table 1. Fate of the introduced
Page 87 and 88: 76 While it is likely that at the o
Page 89 and 90: 78 Pearl Spot The pearl spot, Etrop
Page 91 and 92: 80 Trengganu Enactment No. 8 of 196
Page 93 and 94: 82 References Annual Fisheries Stat
Page 95 and 96: 84 long time ago as shown by the fa
Page 97 and 98: 86 Discussion and Recommendations E
Page 99 and 100: Table 1. Exotic aquatic species int
Page 101 and 102: Table 1. Continued Diseases/Parasit
Page 103 and 104: 92 Fisheries (Piranhas) Rules 1971,
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94 (Caranx ignobilis) golden treval
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96 Table 1. Main species of aquariu
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Status of Introduced Species in Sri
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Exotic Aquatic Species in Taiwan I-
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appreciated in the context of the w
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However, A. anguilla cannot tolerat
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Today, most of these carps are poly
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Caiman latirostris and Alligator mi
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Conclusions The case of the tilapia
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Table 1. Continued Culture Status P
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Table 2. Record of tilapia introduc
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Annex I. Continued Dascyllus melamu
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Exotic Aquatic Species in Thailand
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Present Status of the Exotic Specie
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Table 1 a. Exotic fishes introduced
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Australian Government Position: Int
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There are presently eight State or
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egulate any activity likely to have
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Appendix II. Continued Name State o
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Recommendations of the Workshop 1.0
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(two more to be co-opted) was appoi
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Mr. J. Maclean, do ICLARM, MC P0 Bo
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Appendix I Definitions of Exotics T
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Appendix II Assessment of the Impac
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Table All.3. Assessment of the stat
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Table All.6. Assessment table of th
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Table All.8. Assessment table of th
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Table All.10. Continued Family/Spec
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Table Affi. Indigenous species whic
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Appendix V Existing Legislation or
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TITLES IN THE ASIAN FISHERIES SOCIE
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