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Balasubramanian C.P.,Central Institute of Brackishwater Aquaculture | Cubelio S.S.,National Bureau of Fish Genetic Resources Cochin Unit | Mohanlal D.L.,Central Institute of Brackishwater Aquaculture | Ponniah A.G.,Central Institute of Brackishwater Aquaculture | And 8 more authors.
Mitochondrial DNA | Year: 2016

For several years, mud crabs of genus Scylla have been misidentified owing to their high morphological plasticity and the absence of distinct morphological diagnostic characters. The taxonomic confusion of genus Scylla de Haan is considered to be a primary constraint to the development of aquaculture. Although genus Scylla was revised using morphological and genetic characteristics, taxonomy of Scylla species occurring in India is still not clear. In this study, partial sequences of two mitochondrial genes, 16S rRNA and CO1 (Cytochrome C oxidase subunit I) in populations of Scylla spp. obtained from eleven locations along the Indian coast were used to differentiate and resolve taxonomical ambiguity of the mud crab species in India. The sequences were compared with previously published sequences of Scylla spp. Both trees generated based on 16S rRNA and CO1 indicated that all S. tranquebarica morphotypes obtained during this study and S. tranquebarica sequences submitted previously from Indian waters reciprocally monophyletic with reference sequence of S. serrata. Both sequence data and morphological characters revealed that the species S. serrata (Forskal) is the most abundant followed by S. olivacea. Further, the 16S rRNA and COI haplotypes of Indian S. tranquebarica obtained in the study significantly differed with the known S. tranquebarica by 6.7% and 10.6% respectively whereas it differed with known S. serrata by 0.0-0.7% only, a difference that was not statistically significant. From these studies it is clear that "S. tranquebarica" commonly reported from India should be S. serrata (Forskal). © 2014 Informa UK Ltd.

Mandal A.,Rajiv Gandhi Center for Aquaculture | Varkey M.,Rajiv Gandhi Center for Aquaculture | Sobhanan S.P.,Rajiv Gandhi Center for Aquaculture | Mani A.K.,Rajiv Gandhi Center for Aquaculture | And 5 more authors.
Biochemical Genetics | Year: 2014

The taxonomic ambiguity of the Indian mud crab (genus Scylla de Hann 1833) is still a cause of concern as several papers have been published with misleading identification. This is the first attempt to resolve the taxonomic uncertainty of the mud crab commonly available in Indian coastal waters using molecular genetic markers (ITS-1 and sequencing of COI gene) combined with traditional morphometry. Additionally, we developed a PCR method by which Indian mud crab species can be identified rapidly and effectively. The results clearly indicate that the green morph of the Indian mud crab is Scylla serrata and the brown morph is S. olivacea. The S. serrata commonly mentioned in the literature from India is S. olivacea; the S. tranquebarica noted by many Indian researchers should belong to S. serrata. Caution should be taken when interpreting or implementing the biological, molecular, and aquaculture data in the literature. © 2014 Springer Science+Business Media.

Mandal A.,Rajiv Gandhi Center for Aquaculture | Rao D.,Rajiv Gandhi Center for Aquaculture | Karuppaiah D.,Rajiv Gandhi Center for Aquaculture | Gopalakrishnan A.,Cochin Unit | And 3 more authors.
Gene | Year: 2012

The black tiger shrimp (Penaeus monodon), a commercially important penaeid species, is widely distributed across the Indo-Pacific region. Genetic diversity in P. monodon collected from eight geographical regions in Southwest, East and Andaman coastal waters of India (N=418) was investigated using 10 polymorphic microsatellite loci. Average observed heterozygosity at sampled loci were high, ranging from 0.643 (Coromandel Coast) to 0.753 (South Andaman). Pairwise F ST (ranged from 0.005 to 0.078) and R ST (ranged from 0.005 to 0.171) estimates revealed surprisingly strong and statistically significant genetic structure among tiger shrimp populations. A synthetic map generated by multidimensional scaling shows an apparent cline in allele frequencies paralleling the roughly circular flow of surface currents in the Bay of Bengal. Significant heterozygote deficiencies were noted in most population samples at most loci. Andaman Island sites showed the highest diversity. Recognition of high genetic diversity and distinct population structuring of P. monodon in Indian seas has important implications for future domestication of this species in India, for two reasons: identification of the best wild founding stocks for aquaculture and, subsequently, the potential impacts of release of domesticates to the wild, either accidentally or deliberately (i.e. for stock enhancement). © 2011 Elsevier B.V.

Rimmer M.A.,Fajar University | Thampisamraj Y.C.,Rajiv Gandhi Center for Aquaculture | Jayagopal P.,Rajiv Gandhi Center for Aquaculture | Thineshsanthar D.,Rajiv Gandhi Center for Aquaculture | And 3 more authors.
Aquaculture | Year: 2013

The broodstock of two grouper species, tiger grouper Epinephelus fuscoguttatus and squaretail coralgrouper Plectropomus areolatus, were maintained in sea cages near Rutland Island, Andaman and Nicobar Islands, India, and their spawning performance was monitored from June 2007 to December 2010. E. fuscoguttatus generally spawned monthly in association with the new moon phase, for 8-9. months each year. Each year, they underwent a 3- to 4-month refractory period between February and June then recommenced spawning in May-July. P. areolatus showed a different spawning pattern to E. fuscoguttatus, spawning for less than 6. months each year, also in association with the new moon, and demonstrating much longer refractory periods (up to 15. months) than E. fuscoguttatus. Analysis of temperature data from the sea cage site showed that water temperature was significantly lower during spawning events than during comparable non-spawning periods. We postulate that one factor inhibiting spawning is higher water temperatures exceeding the upper thermal inhibitory limit for both grouper species during the hotter months of the year. Selected broodstock fish of both species were also maintained in onshore tanks fitted with recirculating filtration systems, but the spawning performance of both grouper species in the onshore tanks was inferior to broodstock held in the sea cages. E. fuscoguttatus maintained in onshore tanks spawned during only 5. months of the 42-month study period, whereas E. fuscoguttatus held in the sea cages spawned during 29. months over the same time frame. P. areolatus held in onshore tanks over the same period did not spawn, whereas P. areolatus held in sea cages spawned during 16. months out of the 42-month study period. © 2013 Elsevier B.V.

Aflalo E.D.,Ben - Gurion University of the Negev | Raju D.V.S.N.,Rajiv Gandhi Center for Aquaculture | Bommi N.A.,Rajiv Gandhi Center for Aquaculture | Verghese J.T.,Rajiv Gandhi Center for Aquaculture | And 4 more authors.
Aquaculture | Year: 2012

Sex reversal technology, realized through androgenic gland (AG) manipulation, was recently introduced as a process for production of all-male producing broodstock. This technology exploits however, a relatively small number of sex-reversed broodstock. Thus, both genetic improvement via a breeding program and prevention of inbreeding are needed to ensure the sustainability of such technology. Three wild strains of prawns originating from geographically (though not necessarily genetically) isolated locations in India [Gujarat (G), Kerala (K) and West Bengal (WB)] were assessed for their suitability as breeders for all-male production. In addition, their potential for a selective breeding program was evaluated. A comparative evaluation of early sex segregation, sex reversal, growth performance, and population structure in the three selected strains was performed. Among the purebred strains, after eight months of grow out in earthen ponds, growth performance of the WB strain was the best (59.39 ± 1.08. g), while that of G was the poorest (26.50 ± 0.94. g). Strain-additive genetic effects for body weight at harvest were highest for the WB strain (+ 45.9%) and lowest for the G strain (- 28.3%). Body masses of WB × K and WB × G crosses were 14.2% and 8.8% above the mean mass of the purebred strains, respectively, while that of the K × G cross was 23% below this value. In most crosses, males reached heavier mean body weights than did females with higher frequencies of the large male morphotypes being seen in the WB purebred strain and its respective crosses. Reciprocal effects for body mass ranged from 4% to 14.9% below the mean of the purebred strains. These negative signs mean that in the two crosses involving the WB strain, growth performance is higher when this stain was used as the sire strain. Similarly, the growth performance of the K × G cross was higher when the former was used as the sire strain. Average heterosis effect for body weight was minor (- 0.51 ± 0.73) and did not differ significantly from zero. The high correlation between strain additive effects (the major source of variation in growth) and total performance for body weight (r= 0.927) indicate the existence of valuable genetic variation that could be exploited in a selective breeding program. For all-male production, males from the three strains were segregated at early post-larval stages and microsurgical AG removal was performed. In all the strains, similar low levels of complete sex reversal into functional neo-females (genetic males) were realized (0.17% - 0.34%). These produced relatively small numbers of neo-female to be crossed with normal males to produce the desired all-male population, but raise the possibility that such a process could result in a genetic bottleneck. Thus, a genetic improvement scheme for each strain integrated with periodical crosses of the resulting neo-females from one strain with males from another strain is suggested to avoid inbreeding. © 2012 Elsevier B.V.

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