Barbus paludinosus and Barbus trimaculatus were sampled in Lake Chilwa and the Mnembo River mouth between February 2004 and January 2005, using nets equivalent to those used commercially, to analyse their reproductive biology and distribution as a basis for recommending sustainable fisheries management and conservation practices.
The marine grouper species are considered high value food fish in several countries. However, controlled breeding and hatchery production of grouper fingerlings for commercial farming is still in its infancy. Investigations on the growth performance of the brown marbled grouper Epinephelus fuscoguttatus (Forskal), camouflage grouper E. polyphekadion (Bleeker) and their hybrid (E. fuscoguttatus x E. polyphekadion) under hatchery and growout culture conditions indicate the potential of grouper hybrids for aquaculture.
The use of reproductive and genetic technologies can increase the efficiency of selective breeding programs for aquaculture species. Four technologies are considered, namely: marker-assisted selection, DNA fingerprinting, in-vitro fertilization, and cryopreservation. Marker-assisted selection can result in greater genetic gain, particularly for traits difficult or expensive to measure, than conventional selection methods, but its application is currently limited by lack of high density linkage maps and by the high cost of genotyping.
The WorldFish Center and its research partners have recently made efforts to develop genetically improved carp strains. This paper analyses the comparative performance of the genetically improved carp strains on both average and efficient farms in four carp-dominating Asian countries (Bangladesh, India, Thailand and Vietnam). The results show superior performance of improved strains in terms of body weight and survival rate on both average and efficient farms. On an average farm, the improved carp strain gives 15% higher body weight at harvest in India to 36% higher in Bangladesh.
Bush park fishing / padal fishing is an indigenous fishing method widely employed in the Ashtamudi estuary of Kerala (south India). An artificial reef made from twigs and leaves of trees is planted in the shallow areas of the estuary. The aim is to harvest fish that find shelter in these structures for the purpose of feeding and breeding. Though the State Department of Fisheries has banned this method of fishing in the inland waters of Kerala, 400 padals are operating in this estuary. About 300 of them are anchored in the western parts of the estuary (west Kayal).
Many sources of information that discuss currents problems of food security point to the importance of farmed fish as an ideal food source that can be grown by poor farmers, (Asian Development Bank 2004). Furthermore, the development of improved strains of fish suitable for low-input aquaculture such as Tilapia, has demonstrated the feasibility of an approach that combines “cutting edge science” with accessible technology, as a means for improving the nutrition and livelihoods of both the urban poor and poor farmers in developing countries (Mair et al. 2002).
The high demand for the stinging catfish (Heteropneustes fossilis) and declining wild stocks led the Centre for Aquaculture Research and Extension of India to look for methods for the culture of the species. This paper presents a low-cost, simple breeding technique developed and tested by the Centre that can be easily adopted by rural farmers.
The article is based on an ongoing collaboration in Vietnam between the WorldFish Center (formerly ICLARM) and the Ministry of Fisheries, at the Research Institute for Aquaculture No. 3, Nha Trang City, Khanh Hoa Province. The work described is oriented towards regions near the equator, where induced spawning of on-grown broodstock should be possible over about 10 months of the year. A shorter breeding season (in subtropical areas) would necessitate bigger installations, but a larger market size would have the opposite effect.
Heterosis, direct additive genetic and general reciprocal effects were estimated from a complete diallel cross involving four strains of red tilapia Oreochromis spp from Malaysia, Stirling, Taiwan and Thailand. The mating involved 16 parental female and male breeders per strain, producing 64 full sib families in total, with four full-sib families per cross. Statistical analyses were carried out on 1280 performance records collected in both fresh water (0 ppt) and saline water (30 ppt) environments.
The aim of the overall project of which this report is part is to identify possible solutions for regulating access to aquatic genetic resources and legal protection of the results of research and development in aquaculture using such resources. The case study of the collaborative program on Genetic Improvement of Farmed Tilapias (GIFT) serves as a basis for comparison with two other case studies from Norway on salmon and cod. This study aims to address the following questions: How has the legal regime for GIFT material developed since leaving WorldFish?