Competition for resources is common in aquaculture, which inflates the variability of fish body weight. Selective breeding is one of the effective approaches that may enable a reduction of size variability (or increase in uniformity) for body weight by genetic means. Competition for resources is common in aquaculture, which inflates the variability of fish body weight. Selective breeding is one of the effective approaches that may enable a reduction of size variability (or increase in uniformity) for body weight by genetic means.
Genetic parameters and selection responses were obtained for harvest body weight of blue tilapia (Oreochromis aureus) from data collected over three generations in a selected population. A total of 18 194 records representing 186 sires and 201 dams were used in the analysis. Within generation heritability estimates for harvest body weight ranged from 0.18 to 0.58. When data from more than one generation were included in the analysis, heritability estimates became more stable (0.33–0.40) and it was 0.33 when all data were included in the analysis.
The maintenance of reference populations of Tilapia is discussed, examining genetic considerations to be taken into account to conserve the gene pool to prevent genetic drift and prevent detrimental levels of inbreeding. The importance of knowledge of the proper effective breeding number and its use in management of the reference population is described.
Genetically improved farmed tilapia (GIFT) has undergone ten generations of selection for harvest body weight in Malaysia, but there have been no reports on genetic parameters for flesh characteristics for this strain. In this study the effects of selection for increased harvest body weight on flesh chemical composition (protein%, fat%, moisture% and pH) as well as in colour, were investigated in fillets from fish of the GIFT strain.
A summary is presented of studies undertaken regarding the salinity tolerance of tilapias. The implications of thefindings to the culture of tilapias in Taiwan are considered.
This study was planned to determine the grazing rate of O. niloticus from both toxic and non toxic strains of Microcystis aeruginosa with its effect on fish health through study of some clinical signs, hematological and biochemical parameters.
Tilapia is the main cultured fish species in Egypt, contributing 43.5% of farmed fish production and 24% of total fisheries production. The main problem facing tilapia producers is early reproduction before fish reach marketable size, leading to overpopulation and smaller fish at harvest. Approaches to this problem include the use of all-male hybrids and hand-sexing to remove females.
Production and supply of fish seed-stock are essential for the promotion of aquaculture. Traditional inland aquaculture was based on the collection of seed-stock from rivers and required the sorting and acclimatising of mixed species. Fine meshed nylon net cages ‘hapas’ have been used for this purpose for Chinese carps in China and in Bangladesh and India for Indian major carp for a long time. Hapa nursing of small fry to larger, more predator-resistant fingerlings has been the focus for intensification of aquaculture in North East Thailand and Lao PDR.
Results of the studies undertaken for breeding and nursing Nile tilapia (Oreochromis niloticus) in ricefields in Thai Binh province in Vietnam during the years 1995-96 are briefly presented in this paper.
In many developing countries, availability of suitable tags for use in genetics and aquaculture research has been a problem as they are often expensive and have to be imported from other countries. A simple and inexpensive method used by scientists in Ghana that can be tried and improved by others is described in this article.