Towards Conservation Of The Fresh Water River Terrapin, Batagur Baska: Preliminary Data On The Biology And Development Of Genetic Markers.

The river terrapin, Batagur baska or locally known as tuntung, is a freshwater turtle that inhabit the Southern and SE Asia from West Bengal, India to South Vietnam and Sumatra right down to Peninsular Malaysia

Preliminary study on the natural extenders for artificial breeding of African catfish Clarias gariepinus (Burchell, 1822)

The objective of the present study was to determine the most suitable extender and their respective dilution ratios for African catfish sperm for artificial induced breeding and cryopreservation purposes. Three natural extenders were tested i.e. coconut water, sugarcane water and soybean solutions, at three different levels of sperm to extender dilutions of 1:20, 1:30 and 1:40. While Ringer solution was used as a control Diluted sperm were fertilized with ready isolated eggs to assess the fertility and hatching rate at 0, 6 and 12 hour intervals. The results showed that the eggs hatched approximately 19 to 27 hours after fertilization. In general, the fertilization and hatching rates decreased with increasing dilution ratio. With respect to natural extenders, the coconut water showed the highest fertility and hatching rates at 1:20 dilution ratio. Therefore, coconut water at 1:20 dilution ratio was the optimal condition for African catfish spermatozoa among the natural extenders investigated

Spawning seasons of Rasbora tawarensis (Pisces: Cyprinidae) in Lake Laut Tawar, Aceh Province, Indonesia

Rasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded a critical endangered with populations decreasing in recent years. To date no information on the spawning activities of the fish are available. Therefore, this study provides a contribution to the. knowledge on reproductive biology of R. tawarensis especially on spawning seasons as well as basic information for conservation of the species. Monthly sampling was conducted from April 2008 to March 2009 by using selective gillnets. The gonadosomatic index, size composition and sex ratio were assessed. The gonadal development was evaluated based on macroscopic and microscopic examinations of the gonads. The gonadosomatic index (GSI) varied between 6.65 to 18.16 in female and 4.94 to 8.56 for male. GSI of the female R. tawarensis was higher in March, September and December indicating the onset of reproductive seasons, the GSI and oocyte size being directly correlated with gonadal development stages. Although, a greater proportion of mature male than female was detected during the study, the sex ratio showed that the overall number of female was higher than male. The ovaries had multiple oocyte size classes at every stage of gonadal development, thus R. tawarensis can be classified as a group synchronous spawner or a fractional multiple spawner. The spawning seasons of R. tawarensis were three times a year and September being the peak of the reproductive season and the female was the predominant sex. This species is classified as a group synchronous spawner. (PDF contains 8 pages

Genetic identification of four Malaysian mackerel species off Coast of Peninsular Malaysia based on molecular marker

Random Amplified Polymorphic DNA (RAPD) markers and cytochrome b (Cyt-b) gene sequences were utilized to fingerprint and construct phylogenetic relationships among four species of mackerel commonly found in the Straits of Malacca namely Rastrelliger kanagurta, R. brachysoma, Decapterus maruadsi and D. russelli. The UPGMA dendogram and genetic distance clearly showed that the individuals clustered into their own genus and species except for the Decapterus. These results were also supported by partial mtDNA cytochrome b gene sequences (279 bp) which found monotypic sequence for all Decapterus studied. Cytochrome b sequence phylogeny generated through Neighbor Joining (NJ) method was congruent with RAPD data. Results showed clear discrimination between both genera with average nucleotide divergence about 25.43%. This marker also demonstrated R. brachysoma and R. kanagurta as distinct species separated with average nucleotide divergence about 2.76%. However, based on BLAST analysis, this study indicated that the fish initially identified as D. maruadsi was actually D. russelli. The results highlighted the importance of genetic analysis for taxonomic validation, in addition to morphological traits

DNA barcoding of freshwater fishes from Lake Laut Tawar, Aceh Province, Indonesia

Background. on a short standardized segment of the genome. The main objective of the barcode of life project is to provide a database of genetic sequences which can be used as a tool for universal species identification.  Indonesia has at least 1300 freshwater fish species, however unfortunately no species has been barcoded as yet.  In the presently reported study, we subjected to barcoding a total of 14 species of freshwater fishes from Lake Laut Tawar, Indonesia. Materials and methods. On average, 10 random samples from each species were processed for DNA analysis. Approximately 655-bp were amplified from the 5′ region of the mitochondrial cytochrome C oxidase subunit I (COX1) gene. All obtained sequences were edited and aligned using MEGA 4.0 program. Nucleotide divergence among sequences was estimated based on Kimura 2-parameter distances. Unique haplotypes were determined using DnaSP Version 5.10.02 software, and the genetic relations among haplotypes were assessed by constructing a phenogram using the neighbour-joining method Results. A total of 31 haplotypes from 14 freshwater fish species were produced in this study. The read lengths were 626-bp, where 259 sites were polymorphic, 254 sites parsimony informative, and five singletons. No stop codons, deletions, or insertions were observed in any of the sequences.  The nucleotide distance between species ranged from 7.1%—between Puntius brevis (Bleeker, 1850) and Poropuntius tawarensis (Weber et de Beaufort, 1916)—to 30.4%—between Channa gachua (Hamilton, 1822) and Homaloptera sp.—indicating that P. brevis and P. tawarensis are very closely related. Conclusion. >This study confirms the utility of COX1 gene in accurate identification of 14 species of freshwater fishes from Lake Laut Tawar, however, three species could not be identified to species level namely Rasbora sp. (local name: relo), Homaloptera sp. (ilie) and Clarias sp. (mud). It is suggested that future studies should incorporate morphometric methods to resolve the taxonomic status of these undetermined species

A genome survey sequence (GSS) analysis and microsatellite marker development for Indian mackerel, Rastrelliger kanagurta, using Ion Torrent technology

A next generation sequencing platform (Ion Torrent PGM™) was used to generate a partial genome survey sequence (GSS) dataset to develop microsatellite markers from R. kanagurta genomic DNA. Data generated included a total of 399,794 sequence reads (81.29 Mbp) with 16,209 sequence reads successfully assembled. This produced 327 contigs averaging 677 bp in length in addition to the SSR markers. Results based on GSS BLASTx and BLASTn possessed significant similarity (E value < 10⁻⁶) with available data in public databases, with the majority matching well to previously reported fish sequences. A total of 7891 SSR-containing motif repeats of which 1688 qualified for primer design were generated. After optimization and testing for reproducibility and polymorphism, eight microsatellite markers were deemed suitable for future population genetic analysis in the target species