Chapter 3 Carp Genetic Resources 3.1 Carp Genetic Resources of Bangladesh M.G. Hussain1 and M.A. Mazid1 3.1.1 Introduction gynogenesis and triplody) and sex reversal were Bangladesh, a country dominated by the multiple initiated first (1986-97) and presently stock deltas of the Ganges, Brahmaputra and Meghna improvement of silver barb (Barbonymus River systems, has vast water resources and is also gonionotus), catla (Catla catla) and rohu (Labeo rich in biological diversity with approximately rohita) using selective breeding techniques is in 296 fresh and brackish water fish species progress. In view of conserving biodiversity of (including freshwater prawns) and 511 marine threatened carp species, artificial breeding species (including marine shrimps). Approxi- techniques for Tor putitora, Puntius sarana, Labeo mately 93 per cent of inland fishery resources is gonius, Cirrhinus ariza, Labeo calbasu and L. bata composed of open water bodies like rivers, have been developed. floodplains, natural depressions and Kaptai reservoir, which are the natural breeding grounds 3.1.2 Cyprinid species of for all the endemic freshwater fishes including importance to aquaculture cyprinids. In recent years, inland open water fisheries have been under heavy pressure due to 3.1.2.1 Endemic cyprinid species the deterioration of environmental conditions: siltation and soil erosion in river basins; water The endemic cyprinid species of Bangladesh can pollution from industrial, agricultural and be divided into two sub-groups: (i) “major” carps municipal wastes; construction of embankments (e.g. C. catla, L. rohita, Cirrhinus cirrhosus, L. calbasu); for flood protection; injudicious and destructive (ii) “minor” carps (e.g. L. bata, C. ariza, L. nandina, fishing practices; outbreak of diseases; and loss of L. gonius). Most of the freshwater river systems and natural breeding grounds as a result of habitat floodplains of the country are the natural breeding degradation. The reduced carrying capacity and grounds for all the major and minor carps. There productivity of most of the aquatic environments are at least 13 endemic species of carps, from 6 has affected fish biodiversity. Owing to such genera, which are of interest to aquaculture in natural and man-made changes, a good number Bangladesh (Table 3.1.1). of valuable fish species dwelling in freshwater ecosystems have become threatened or Table 3.1.1. List of endemic cyprinid species of Bangladesh of endangered and some already face the threat of interest to aquaculture extinction. Species Common name Local name Labeo rohita Rohu Rui Although the government is making strenuous Catla catla Catla Katla efforts to rehabilitate the inland fisheries, it has Cirrhinus cirrhosus Mrigal Mrigal focused its attention on aquaculture, which has a Cirrhinus ariza Reba Bhangan tremendous potential for development. To avoid Labeo calbasu Calbasu Kalibaush loss of genetic diversity and inbreeding in Labeo bata Bata Bata hatchery populations, development of improved Labeo boga Boga labeo Bhangan brood stocks through implementation of effective Labeo gonius Gonius Gonnia breeding plans and genetic stock improvement Labeo nandina Nandina labeo Nandil programs for commercially important carp Bengala elanga Bengala barb Along species has recently been identified as an Puntius sarana Barb Sarpunti important area of research (Hussain and Mazid Tor tor Tor mahseer Mahashoal 1999a). Genetic studies on carp species using the Tor putitora Putitor mahaseer Mahashoal techniques of chromosome manipulation (viz. Source: Rahman (1985), Hasan (1990) and Hussain and Mazid (2001). 1 Bangladesh Fisheries Research Institute, Mymensingh 2201, Bangladesh. 16 WorldFish Center | Carp Genetic Resources for Aquaculture in Asia CHAPTER 3.1 | Carp Genetic Resources Of Bangladesh 17 All the species belonging to the major carp sub- different species of introduced species of carps, group are the natural inhabitants of the freshwater made on the basis of these records, is in Table sections of the rivers of Bangladesh, Burma, 3.1.2. Additionally, stocks of silver carp northern India and Pakistan (Jhingran and Pullin (Hypophthalmichthys molitrix), bighead carp 1985). In Bangladesh, these species are mostly (Aristichthys nobilis) and grass carp found in the Padma-Brahmaputra River system (Ctenopharyngodon idella) were obtained from (i.e. Padma, Jamuna, Arial Khan, Kumar and Old wild populations in China. Among the introduced Brahmaputra rivers) and the Halda River system carp species, H. molitrix, C. idella, A. nobilis, in Chittagong. Their favorite habitat is the deep common carp (Cyprinus carpio), black carp pools of these rivers. During the monsoon time (Mylopharyngodon piceus), B. gonionotus and Tor they breed in the inundated rivers and flowing spp. are predominant. waters. Mahseer (Tor spp.) are the inhabitants of hilly streams of Mymensingh, Sylhet, Dinajpur All these indigenous and exotic carps are used in districts and Kaptai Lake of the Chittagong Hill polyculture in ponds. Some are stocked in tracts. The natural spawning grounds of Tor spp. floodplains, rivers and reservoirs to enhance consist of a sandy bottom, pebbles and aquatic fishery production. weeds, where temperatures are relatively low and dissolved oxygen is sufficient (Pathani 1982). 3.1.2.3 Induced breeding of fish and recent decline in quality of hatchery On the other hand, all the other species belonging stocks to the minor carps are the natural inhabitants of small rivers and floodplains. Shallow freshwater The recent advancement of aquaculture, in zones of the North-East (Mymensingh, Netrokona particular the carp polyculture and freshwater fish and Mohanganj), South-West (Faridpur and farming in rice fields, seasonal ditches, canals and Jessore) and North-West (greater Rajshahi area) perennial ponds, is mainly due to the advent of floodplains in Bangladesh are the natural habitat induced breeding or artificial propagation of minor carps. They naturally breed there and techniques by hypophysation during the late grow to maturity within a short period of time 1950s. In Bangladesh, the production of seed of (10-12 months). endemic carps through artificial breeding has become a common practice since 1967 (Ali 3.1.2.2 Exotic carp species 1967). Meanwhile, Chinese carps, exotic barbs and catfishes have been introduced and a large Although Bangladesh is rich in endemic fish number of hatcheries in the private sector genetic resources, introduction of different (estimated to be about 635) have been established species of fish (mostly Chinese carps) has (Ali 1998). These hatcheries presently contribute occurred since 1960. Such introductions of exotic more than 98 per cent of the total spawn (three- fish species have not been properly recorded. The day-old hatchlings) production (see Table 3.1.3) only document describing these introductions is and the rest, a very negligible proportion, is by Rahman (1985). Subsequently, BFRI collected from natural sources, mainly rivers and maintained its record of new fish introductions their tributaries (Banik and Humayun 1998). for research purposes (Hussain 1997). A list of Table 3.1.2. List of introduced cyprinid species of Bangladesh Species Common name Source Year of introduction Ctenopharyngodon idella Grass carp Hong Kong 1966 Nepal 1979 Japan 1970 Mylopharyngodon piceus Black carp China 1983 Hypophthalmicthys molitrix Silver carp Hong Kong 1969 Aristichthys nobilis Bighead carp Nepal 1981 Cyprinus carpio var. communis Common carp China 1960 Vietnam 1995 Cyprinus carpio var. specularis Mirror carp Nepal 1979 Hungary 1982, 1996 Barbonymus gonionotus Silver barb Thailand 1987, 1994 Tor putitora Putitor mahseer Nepal 1991 Source: Rahman (1985), Hasan (1990) Hussain (1997) and Hussain and Mazid (2001). 16 WorldFish Center | Carp Genetic Resources for Aquaculture in Asia CHAPTER 3.1 | Carp Genetic Resources Of Bangladesh 17 Table 3.1.3. Number of fish hatcheries and spawn (three-day-old Table 3.1.4. List of threatened cyprinid species of Bangladesh hatchlings) production in Bangladesh Scientific Local Critically Endangered Year No. of hatcheries Spawn production (kg)1 Name name Endangered Public Private Natural Hatcheries Labeo nandina Nandil X sector sector sources Labeo boga Bhangan X 1988 77 162 12 533 6 849 Labeo gonius Ghonnia X 1989 84 185 12 236 5 664 Labeo bata Bata X 1990 89 204 5 128 14 773 Labeo pangusia Ghora X 1991 89 218 6 855 24 683 maach 1992 89 222 9 342 35 851 Labeo calbasu Kalibaush X 1993 102 256 5 069 48 964 Cirrhinus ariza Bhangan X 1994 102 389 5 872 72 536 Puntius sarana Sarpunti X 1995 141 502 9 144 88 272 Puntius ticto Tit punti X 1996 141 600 2 399 103 615 Tor tor Mahashoal X 1997 141 631 2 824 115 888 Tor putitora Mahashoal X 1998 141 635 2 885 117 700 Source: Hussain and Mazid (1999a, 2001). 1 1 kg spawn = approximately 400 000 three-day-old hatchlings Source: Hussain and Mazid (1999b, 2001). Recently, in Bangladesh it has been reported that differences, i.e. differences in meristic traits of hatchery produced stock, mainly the carps, have wild and hatchery stocks of L. rohita and morpho- shown reduction in growth and reproduction meristic characters, including gonadal differences, performances, increased morphological deformities, of intraspecific hybrid groups of B. gonionotus disease and mortalities, etc. This is probably due to were analyzed. genetic deterioration in the hatchery stocks as a result of poor fish brood stock management (i.e. L. rohita unconscious negative selection and use of undesirable size of breeders for mating), inbreeding For the stock improvement program, L. rohita and depression (due to sib or parent-offspring mating) C. catla wild stocks were obtained from different and ignorance of private hatchery managers river systems of Bangladesh. Initial trials were regarding overall brood stock management and conducted with L. rohita to investigate whether hatchery operation. Such poor brood stock any phenotypic (meristic traits) differences management and close mating of breeders results in existed among the wild stocks (from the inbred or highly homozygous hatchery populations Brahmaputra, Halda and Jamuna Rivers) and a leaving adverse effects on aquaculture production as hatchery stock.