WorldFish annual report 2011/12

This year's report contains the Director General's and Chairman's statements. Also highlighted in the reports, are stories of projects with different partners: 1) CGIAR Research Program on Aquatic Agricultural Systems (AAS) in Zambia. 2) Wetland Alliance project in the Mekong delta. 3) Projects with CARE, the humanitarian organisation in Egypt. 4) Tilapia breeding program with Water Research Institute (WRI) in Ghana. 5) Partnerships with the private sector on sustainable aquaculture enterprise in developing countries.

Genotype by production environment interaction in the GIFT strain of Nile tilapia (Oreochromis niloticus)

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.

Genetic improvement of Israeli blue (Jordan) tilapia, Oreochromis aureus (Steindachner), through selective breeding for harvest weight

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.

Relative performance of two Nile tilapia (Oreochromis niloticus Linnaeus) strains in Egypt: The Abbassa selection line and the Kafr El Sheikh commercial strain

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).

Growth and survival rate of three genetic groups fed 28% and 34% protein diets

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.

Genetic improvement of farmed tilapias: Genetic parameters for body weight at harvest in Nile tilapia (Oreochromis niloticus) during five generations of testing in multiple environments

The main objective of this paper was to report more reliable estimates of the genetic variation and the genotype by test environment interaction for harvest body weight in the GIFT population in the Philippines than could be obtained from the base population by using the data from the five generations following the base population and that covers a wider span of test environments than the later experiments referred to above. Included are also estimates of the genotype by sex interactions for body weight.

Donor-oyster derived heritability estimates and the effect of genotype X environment interaction on the production of pearl quality traits in the silver-lip pearl oyster, Pinctada maxima

The aim of this study was to estimate donor-oyster derived heritability and genetic correlations for pearl quality traits in the silver-lipped pearl oyster, P. maxima; namely pearl size, colour, lustre, shape and complexion. As future breeding programs for pearls are likely to involve oysters that will be reared in geographically disparate locations we also evaluated the potential impact environment G × E interactions may have on the realization of genetic gains for pearl quality traits.

A comparison of communal and separate rearing of families in selective breeding of common carp (Cyprinus carpio): Responses to selection

The genetic response in growth traits in a selection program for increased harvest weight in a common carp population in Vietnam is reported. A base population (G0) was established from six carp stocks using single pair mating. Selection was based on high breeding values for body weight at harvest, with a corresponding control group selected on average breeding values of the population.

Can the global adoption of genetically improved farmed fish increase beyond 10%, and how?

The annual production from global aquaculture has increased rapidly from 2.6 million tons or 3.9% of the total supply of fish, shellfish and mollusks in 1970, to 66.7 million tons or 42.2% in 2012, while capture fisheries have more or less leveled out at about 90 million tons per year since the turn of the century. Consequently, the future seafood supply is likely to depend on a further increase of aquaculture production. Unlike terrestrial animal farming, less than 10% of the aquaculture production comes from domesticated and selectively bred farm stocks.

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