Breeding programs for carp species carried out in a number of Asian countries have delivered genetically fast growing strains to farmers and producers. The economic benefits resulting from the programs are substantial. The genetic improvement of carp is one of the most profitable and sustainable ways to help poor communities in developing countries in the region.
Silver barb (Pontius gonionotus) is widely distributed in Southeast Asia. In addition to Vietnam, the species is found in Thailand, Cambodia, Lao, Malaysia, Indonesia, Bangladesh etc. In Vietnam, the species is abundantly represented in the Mekong Delta and has a wide distribution in Southern Vietnam (Dong Nai, Tien Giang, Vinh Long, Can Tho, Soc Trang, An Giang etc.)
This chapter presents the results from a selective breeding experiment with Nile tilapia in a low input pond environment. The environment was defined as low input as the pond only received chicken manure for fertilisation. No pellets were given to the fish during larval rearing or grow out. The results show that good growth can be obtained under these conditions. Heritability for growth was high (0.6) and harvest body weight almost doubled over two generations of selection.
The Project consists of two phases, Phase I focusing on determining research priorities leading to the development of high yielding breeds and strains; documentation of carp genetic resources, documentation of carp genetic improvement and initiation of breeding programs; and Phase II concentrating on (i) continued development of improved breeds, (ii) dissemination and evaluation of improved carp species, and (iii) establishment of carp breeding programs. The Asian Development Bank (ADB) provided a Technical Assistance Grant (RETA No. 5711) for implementing Phase I.
The role of carcass evaluation techniques in aquaculture research programs, especially in genetics, breeding, production management, feeding and nutrition, cannot be overemphasized. Knowledge of production efficiencies and growth potentials in relation to desired carcass attributes has provided an impetus to improvements in genetic selection techniques and management of aquatic food animals. Accurate, standard and uniform methods of carcass evaluation are critically important. A standard format developed for collection of data on carps is presented in this paper.
At least 60 species of crustaceans are farmed experimentally or commercially, mostly in the tropics and subtropics where species maturation times are shorter than in temperate climates. Over 50 species are kept by aquarists, and several, especially Artemia spp., are widely used as live foods for rearing fish and aquatic invertebrates. However, there has been far less application of genetics in crustacean farming than in finfish and mollusc farming, and very few crustaceans can be regarded as domesticated.
Selection response for body weight at marketable size was measured for channel catfish, Ictalurus punctatus, grown in earthen ponds at 7500 fish/ha. Three generations of mass selection for increased body weight in Kansas and Marion strains of channel catfish increased body weight from 453 to 583 g or 29%, and from 530 to 642 g or 21%, respectively, with cumulative realized heritabilities of 0.17 ± 0.016 and 0.19 ± 0.012, respectively. Realized heritabilities for the third generation alone were 0.16 ± 0.016 and 0.23 ± 0.015 for Kansas and Marion strains, respectively.
Total freshwater aquaculture production in Vietnam in 1995 was about 300 000 tons and total brackish water aquaculture production was about 115 000 tons. Total tilapia production was about 15 000 tons, mainly produced in fresh water. Until now, most of the production has been based on Mozambique tilapia, that was introduced in Vietnam in 1951 and after the introduction of Nile tilapia from Taiwan in 1973, also on hybrids between Mozambique and Nile tilapia.
Human and institutional capacities for developing and managing genetically improved tilapia in Africa are discussed. Discussions are related particularly to the status of hatcheries, rearing facilities, research and extension services, training in genetic enhancement, and fish transfer in major aquaculture countries in Africa. The leading aquaculture producing countries are Egypt and Nigeria along with nine other countries with some intermediate levels of fi sh production. The availability of quality fry and fingerlings constitutes a major constraint.