Characterization of different strains of common carp (Cyprinus carpio L.) using molecular markers is essential for the management of this fish in respect to the evaluation of the potential genetic effects induced by hatchery operations and the genetic improvement of carp varieties. Five microsatellite loci (MFW1, MFW2, MFW11, MFW15 and MFW20) were analyzed for the molecular characterization of four common carp strains, i.e. scaled carp, mirror carp, red carp and koi carp. We observed differences in heterozygosities and the average numbers of alleles but not in polymorphic loci (P 95 ) among the strains. Koi carp displayed the highest level of variability in terms of heterozygosity. The N m values and the F ST values indicated a low level of gene flow and high level of differentiation among the strains. The highest genetic distance was observed between the scaled carp and the koi carp whilst the lowest genetic distance was found between the red-and koi carp. The unweighted pair group method with averages (UPGMA) dendrogram resulted in two clusters, one containing only the scaled carp and the other the remaining three varieties. Microsatellite markers have been found to be effective tools for characterization of different strains of common carp.

Summary Accounting for genetic diversity and evolutionary processes has long been recognised as an important goal in conservation planning. However, because genetic data are often lacking, surrogate approaches are widely used. Few studies have, however, assessed the capacity of surrogate data, such as higher taxonomic levels (e.g. species distributions) to portray intraspecific genetic diversity. Here, we contrast conservation plans based on traditional species distribution data, with those derived from intraspecific genetic data for a smaller subset of species, both using freshwater fish in northern Australia. We modelled the spatial distribution of 46 species and intraspecific genetic diversity within four common species. We then identified priority areas for conservation using both data sets and evaluated the extent to which solutions obtained from species distribution data portrayed genetic diversity. We found that genetic diversity could be adequately represented within priority areas identified using species distribution data, even at low conservation targets and for species with complex genetic structure. However, this was only true when using the entire fish community (i.e. all 46 species). In contrast, a substantial component of the genetic structure would not be represented in conservation priority areas when using a subset of species. Our results have important implications for the use of surrogates for genetic diversity in conservation planning. Sufficient genetic diversity might be represented in conservation priority areas by including a broad range of species with distributions ranging from common to rare elements in the community in the prioritisation analyses. We recommend focusing on improving accuracy of data on species distributions to reduce uncertainties in conservation recommendations derived from commission and omission errors, to avoid misuse of limited conservation funds and potential failure of conservation practice.

An experiment was carried out to evaluate the growth performance of carp polyculture system supplemented with different levels of supplementary feed. To undertake this investigation, two earthen ponds were stocked with 25% Labeo rohita, 25% Catla catla, 20% Labeo calbasu, 20% Ctenopharyngodon idella and 10% Hypopthalmichthys molitrix with a total stocking density of 10000/ha. The net fish production was found to be 2,166 and 3,874 kg/ha/yr in pond-01 and pond-02, respectively. The total cost of fish farming of pond-01 and pond-02 were 64,268 BDT and 88,568 BDT per ha. The total return of pond-01and pond-02 were BDT 1,04,280 BDT and 1,69,250 BDT per ha. Net benefit from pond-01 and pond-02 was 40,312 BDT and 80,682 BDT respectively. Net profit margin of pond-01 and pond-02 was 62.73% and 91.10%. And finally the benefit cost ratios (CBR) were found to be 0.62:1 and 0.91:1 in pond-01 and pond-02, respectively. Asiat. Soc. Bangladesh, Sci. 42(2): 229-234, December 2016