The Abbassa selection line (developed by selective breeding) and the Kafr El Sheikh commercial strain (widely used in Egypt), both Oreochromis niloticus, were compared at two stocking densities (two and four fish m-2). Harvest weight, length, depth, width and head length were recorded. The Abbassa line showed a superior harvest weight (28 per cent) over the Kafr El Sheikh strain. Males were heavier than females, but the between-sex difference was greater in the commercial than in the Abbassa line (39 and 31 per cent respectively).
To satisfy increasing demands for fish as food, progress must occur towards greater aquaculture productivity whilst retaining the wild and farmed genetic resources that underpin global fish production. We review the main selection methods that have been developed for genetic improvement in aquaculture, and discuss their virtues and shortcomings. Examples of the application of mass, cohort, within family, and combined between-family and within-family selection are given.
The development of a saline tolerant tilapia strain able to grow fast is of importance in the Philippines, where 240 000 ha of brackish water ponds are available. To this end, founder hybridization between Oreochromis niloticus (with favorable growth traits) and O. mossambicus (with favorable salinity tolerance traits) was performed and followed by backcrossing with O. mossambicus to develop a strain highly tolerant to saline environments. Genetic selection for growth performance was subsequently conducted.
The CGIAR Research Program on Livestock and Fish started in January 2012. It aims to increase the productivity of small-scale livestock and fish systems in sustainable ways, making meat, milk and fish more available and affordable to poor consumers across the developing world. Genetics is one of the three technological components of the Livestock and Fish research program. A genetics team meeting was held on 30-31 July 2012, at the International Livestock Research Institute (ILRI), Nairobi.
This study investigates the genetic structure and phylogeography of a broadcast spawning bivalve mollusc, Pinctada maxima, throughout the Indo-West Pacific and northern Australia. DNA sequence variation of the mitochondrial cytochrome oxidase subunit I (COI) gene was analysed in 367 individuals sampled from nine populations across the Indo-West Pacific.
Social interactions often occur among living organisms, including aquatic animals. There is empirical evidence showing that social interactions may genetically affect phenotypes of individuals and their group mates. In this context, the heritable effect of an individual on the phenotype of another individual is known as an Indirect Genetic Effect (IGE). Selection for socially affected traits may increase response to artificial selection, but also affect rate of inbreeding.
The strain by nutrition interaction in body weight and survival rate was examined by testing three genetic groups (Selection and Control lines of the GIFT strain, and Red tilapia) at two levels of protein in the diet (28% and 34%). The GIFT strain of Nile tilapia (Oreochromis niloticus) has been selected for high-breeding values for body weight, whereas the Control was contemporaneously maintained and selected for breeding values of body weight close to the population mean. The Red tilapia (Oreochromis spp) was unselected at the time of the experiment.
Three discrete generations of GIFT fish (Nile tilapia strain, Oreochromis niloticus; a total of 10,065 fish with pedigree and phenotypic information) were tested in pond and cage culture environments to determine genotype by production environment interaction between both environments in Malaysia. Live weight (selected trait), standard length, body depth and width were recorded. A bivariate animal model was used to estimate variance and covariance components, whereby the homologous body traits in pond and cage environments were treated as genetically distinct traits.
This viewpoint paper explores the potential of genomics technology to provide accurate, rapid, and cost efficient observations of the marine environment. The use of such approaches in next generation marine monitoring programs will help achieve the goals of marine legislation implemented world-wide. Genomic methods can yield faster results from monitoring, easier and more reliable taxonomic identification, as well as quicker and better assessment of the environmental status of marine waters.
Macrobrachiurn rosenbergii is one of the widely cultured freshwater prawn species globally. India was the third largest producer of this species in 2007 and its aquaculture production rose to 43,000 metric tons (t) in 2005 froin less than 500 t in 1995. However, since then production has been declining and in 2008-09 it was 12,856 t, a reduction of more than 70% compared to 2005. There are several contributing factors to this decline, such as slow growth rate, poor survival, disease outbreaks, increase in cost of production, and availability of low risk alternative fish species.