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species for food and space, again leading to poor growth, this time among other species of fish. By the early 1960's, tilapia began to be regarded as a nuisance. In a bid to overcome problems inherent in 0. mossambicus culture, attempts were made to develop all-male hybrids. Hickling (1960) experimented on hybridization and as a result of his experiments Oreochromis niloticus, 0. hornorum, Tilapia zulu and T. rendalli were introduced into Malaysia. He was successful in obtaining an all-male hybrid (0. mossambicus x 0. hornorum), but it did not find lasting commercial success in Malaysia. This is because hybrids were contaminated by stray 0. mossambicus. In 1972, the Department of Fisheries officially ceased all production of 0. mossambicus in its hatcheries. A policy of discouraging its culture was also instituted. The policy was revised only in 1975, with the recognition of 0. niloticus as an acceptable alternative. While 0. niloticus was originally brought into Malaysia in the 1960's, pure lines were not maintained. Therefore, in 1979 a stock of pure 0. niloticus consisting of 400 individuals was imported from Chengmai, Thailand, and raised in the Department of Fisheries hatchery of Jitra, Kedah. This stock constituted the broodstock for all the Department hatcheries to the present. The Department of Fisheries first imported six red tilapia from Thailand in 1981. A second importation consisting of 500 individuals was made from Thailand in the same year. In 1982, a stock of red hybrids was imported from Taiwan and maintained in the Freshwater Fisheries Center, Bukit Tinggi, to prevent interbreeding with wild stock or with each other. Red tilapia found a lucrative urban market, and before long commercial culture of red tilapia started. However, soon demand outstripped production by 12.7% in 1983, 22.5% in 1984, 24.7% in 1985 and 19.6% in 1986. The industry was also very substantially different from the one that raised 0. mossambicus thirty years earlier. Tilapia was then raised by small farmers in ponds and mining pools using semi-intensive and extensive methods. The red tilapia, while still relying substantially on such methods, saw the proliferation of commercial, intensively operated farms using formulated feeds and high rates of water exchange. Markets have also changed. Where 0. mossambicus was sold fresh at the wet markets, red tilapia is consigned mainly to the restaurant trade which demands live fish. Live red tilapia is also sold in specific supermarkets under the name red snapper or cherry snapper. There is little documented evidence of impact of the tilapia in Malaysian waters. The proliferation of 0. mossambicus particularly in mining pools and lakes, is generally recognized as having affected local icthyofaunal populations but the species affected and extent to which they have been affected is not documented. The massive importation of red tilapia fry may have brought in non-indigenous epizootics. A lack of suitable baseline information on the fish disease status of the country however, prevents any meaningful comparisons. Red tilapia (particularly those not treated for monosexuality) are no less prolific than 0. mossambicus. It is no longer uncommon to see mining pools filled with red tilapia fry and stunted red fish. These fry have undoubtedly escaped into rivers and streams, where they proliferate, breeding either with themselves or with wild 0. mossambicus stock. At this point in time, red tilapia have yet to match the widespread distribution of 0. mossambicus. Whether they will or not is an open question and will depend on their hardiness and their capability to compete with resident animals. 77
78 Pearl Spot The pearl spot, Etroplus suratensis, which is a brackishwater cichlid found in India and Sri Lanka (Ong 1983) was introduced to Sarawak, Malaysia from Sri Lanka in 1975 (Welcomme 1981). The species breeds readily in freshwater or brackishwater, in ponds. They, however, are not found in large quantities in natural bodies of water. Catfishes The catfish Clarias macrocephalus was introduced in 1950 from Thailand (Tweedie, 1952) and has been able to propagate in swampy ditches and is also found in paddy fields and pools. It can be cultured in ponds. Although they can breed naturally in swampy areas, they have not been able to compete with the indigenous catfish, Clarias batrachus. Javanese Carp The Javanese carp, Puntius gonionotus, locally called Lampam Java, was first Fitroduced in 1953 (Welcomme 1981). Stock obtained from Indonesia was raised in the Tahpah Fish Breeding Center in Perak (Somasekheran, pers. comm.). In the late 1960's further introductions of P. gonionotus stock, this time from Thailand, were made. The fish was bred with existing broodstock and the progeny were distributed among the Department's five breeding stations. The last importation of P. gonionotus stock was from Indonesia (Soong 1963). Javanese carp is one of the most popular cultured fish in Malaysia. In 1986, some 969 t of fish were raised by fish farmers amounting to a total wholesale value of M$ :2.76 Million, ranking second after the Chinese major carps in the freshwater aquaculture industry (Table 3). However, while Chinese major carps are raised by commercial fish farmers, the Javanese carp is highly preferred by subsistence farmers. It is also the primary species involved in the Department of Fisheries open-water stocking program since the 1960's. The importance of the Javanese carp is underscored by the production figures of Government freshwater breeding centers. The release of Javanese carp in public waters over the last 20 years has established this species as part of the Malaysian icthyofauna. The fish is caught by subsistence fishermen mainly to supplement domestic requirements. There is however, no commercial fishery. As with other fish, it is very difficult to evaluate the environmental impact of the Javanese carp. There is no evidence that the Javanese carp has displaced any indigenous puntid species. Indian Major Carps The Indian major carps, i.e., catla, rohu and mrigal were imported from Calcutta in 1960 and raised in the Tapah Fish Breeding Station (Welcomme, 1981). Part of this stock was removed to the Freshwater Fisheries.<strong>Research</strong> Station at Malacca. The culture of the Indian major carps has not proved popular. However, rohu is still cultured in the states of Negeri Sembilan and Malacca to a limited extent. Rohu fry are also produced on an ad hoc basis by the Freshwa:er Fisheries <strong>Research</strong> Station in Malacca and are consigned entirely to the open water stocking program.
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Exotic Aquatic Organisms in Asia /
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Exotic Aquatic Organisms in Asia Pr
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The Introduction of Exotic Aquatic
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Introduction This special publicati
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help to promote national awareness
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Conditions in Europe and North Amer
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2 taken as the basis for the introd
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4 with respect to other introductio
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6 Costa-Pierce, B. 1988. Study miss
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8 extinction of the endemic rainbow
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10 bottom substrates by European ca
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12 Arthington 1988; Lloyd 1987); G.
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14 Apparent Extinction of the Lake
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16 successful and more often than n
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18 Reznick, D. 1981. 'Grandfather E
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20 -24° 4' 4 - I- .300 Cl) '1 S 36
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22 The terminology associated with
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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 56 and 57: Impact of Exotic Aquatic Species in
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: 76 While it is likely that at the o
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,
Page 105 and 106: 94 (Caranx ignobilis) golden treval
Page 107 and 108: 96 Table 1. Main species of aquariu
Page 110 and 111: Status of Introduced Species in Sri
Page 112 and 113: Exotic Aquatic Species in Taiwan I-
Page 114 and 115: appreciated in the context of the w
Page 116 and 117: However, A. anguilla cannot tolerat
Page 118 and 119: Today, most of these carps are poly
Page 120 and 121: Caiman latirostris and Alligator mi
Page 122 and 123: Conclusions The case of the tilapia
Page 124 and 125: Table 1. Continued Culture Status P
Page 126 and 127: Table 2. Record of tilapia introduc
Page 128 and 129: Annex I. Continued Dascyllus melamu
Page 130 and 131: Exotic Aquatic Species in Thailand
Page 132 and 133: Present Status of the Exotic Specie
Page 134 and 135: Table 1 a. Exotic fishes introduced
Page 136 and 137: 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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