Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Phenotypic and genotypic identification of Aeromonas species from aquatic environment 3 20 EN Shashi Yadav Dev Kumar Verma Pravata Kumar Pradhan Anoop Kumar Dobriyal Neeraj Sood A total of 50 strains of Aeromonas spp. were isolated from 50 water and fish samples, and identified biochemically and genetically. Biochemical characterization indicated that 20 out of 50 aeromonads were A. veronii, 19 were A. caviae, 9 were A. hydrophila and 2 were A. trota. Molecular identification of isolated aeromonads revealed restriction profile of four species i.e. A. sobria, A. media, A. allosaccharophila and A. schubertii in addition to A. veronii, A. caviae, A. hydrophila and A. trota in 16S rDNA RFLP. The 16S rDNA sequencing results for the 13 strains validated the results of PCR-RFLP analysis for Aeromonas identification. Most of the isolates identified by 16S rDNA RFLP were positive for virulence factors as revealed by phenotypic tests such as hemolysin production, casein hydrolysis, gelatinase activity, lipase activity, DNase activity, lecithinase production and siderophore production. Further, a variable number of Aeromonas spp. was positive for lipase and elastase genes indicating the presence of other genes responsible for these activities observed phenotypically. The present study highlights important incidence of motile Aeromonas spp. with virulence potential, from water and fish samples. Aeromonas,16S rDNA,RFLP,virulence http://www.journal-aquaticscience.com/article_73488.html http://www.journal-aquaticscience.com/article_73488_9d41772ab5dfba9a86bbb427a8ef3d02.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 An Appraisal of the Feasibility of Tilapia Production in Ponds Using Biofloc Technology: A review 21 39 EN Erick Ochieng Ogello Safina M. Musa Christopher Mulanda Aura Jacob O. Abwao Jonathan Mbonge Munguti The continuous expansion of aquaculture sector has no doubt triggered debate on environmental issues and has accelerated global demand for fishmeal and fish oil in equal measure. In the recent past, scientists have described bioflocs and periphyton technology as self sustaining biotechnology units capable of purifying aquaculture waste water and manufacturing fish food simultaneously. Based on literature evidence, the authors wish to show potential of biofloc technology (BFT) towards improving yield, safety and economic sustainability of cultured tilapia. In addition to fish feed dilemma currently threatening aquaculture sector, this paper describes the concept and dynamics of BFT as possible solution. Tilapia productivity and added values have also been addressed. The BFT works on the basis of recycling nutrients by maintaining high C/N ratio, which stimulates heterotrophic bacteria that converts ammonia into microbial biomass making it possible for protein to be eaten twice (in feed and microorganism) by cultured fish. Although bioflocs contain adequate protein, lipid, carbohydrates and fatty acids, they also ensure biosecurity thus protecting fish from variety of disease infections. Tilapia growth rates of up to 0.3 g.day-1 yielding up to 300 mt.ha-1 has been reported in well managed bioflocs ponds. Also, significant reduction of fish feed by up to 20% has been reported thus lowering total production cost in biofloc aided ponds. Even though the exact mechanisms influencing bioflocs are unknown, the paper describes biological, chemical and physical interactions as possible dynamics shaping microbial communities in bioflocs. The bioflocs technology is inexpensive thus making it the forgotten asset for present and future aquaculture. In this respect, authors suggest that a strategy to have a predominance of easily digestible bacteria containing energy rich compounds should be of particular interest in promoting BFT in aquaculture sector. Bio-floc technology,Fish food,periphyton,C/N ratio http://www.journal-aquaticscience.com/article_73489.html http://www.journal-aquaticscience.com/article_73489_f88d6284e29c36aac48bdac5b63451e5.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Length-weight relationship, body shape variation and asymmetry in body morphology of Siganus guttatus from selected areas in five Mindanao bays 40 57 EN Anabelle Dece J. Angeles Jessie G. Gorospe Mark Anthony J. Torres Cesar G. Demayo This study was conducted to describe length-weight relationship, body shape, and asymmetry in body morphology of S. guttatus and their possible implication in broodstock selection and aquaculture. Shape analysis was done applying the method of geometric morphometrics. The length (L)-weight (W) relationships (LWR) were estimated using the equation, W=aLb. Fluctuating asymmetry analysis was performed in each sex using landmark coordinates and six morphologic characters measured for both right and left lateral side. Results revealed variations in body shapes between sexes and populations of the fish, the LWR of female and male S. guttatus show positive and negative allometric growth respectively. In females, this could be attributed to the capability of rearing large number of eggs. Variations in body shapes, large body area, heavier body and longer body length were the characteristics of adult S. guttatus identified to be possibly the most favorable characters which could produce high quality recruits for aquaculture purposes. Allometry,Fluctuating aymmetry,broodstock,aquaculture http://www.journal-aquaticscience.com/article_73490.html http://www.journal-aquaticscience.com/article_73490_1d831d623e6fbfee446217913107d619.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Genetic diversity of commercial species of the tilapia genus Oreochromis in Mexico 58 66 EN Breidy Lizeth Cuevas-Rodríguez Manuel Parra-Bracamonte Manuel García-Ulloa Ana María Sifuentes-Rincón Hervey Rodríguez-González Molecular techniques such as the DNA markers are commonly used to examine intra and interpopulation variation among fish strains. The objetive of this work was to analyze the genetic diversity of three tilapia species (Oreochromis aureus, O. mossambicus and O. niloticus) cultured in Mexico, through the DNA markers, genetic and allele frequencies, number of alleles, endogamy, estimated and expected heterozygosity (He), and conformation of Hardy Weingberg, (H-W). After 150 culture days, a total of 24 individuals for each fish species were genotyped using a panel of 8 microsatellite markers. The result showed that the mean number of alleles per locus and heterozygosity for each tilapia species were 19 and 0.442, respectively. The diversity indices showed that O. aureus was more variable (He=0.813) followed by O. niloticus (HE=0.789) and O. mossambicus (HE = 0.552). Mean endogamy values fluctuated from 0.314 for O. niloticus to 0.436 for O. aureus. Highly significant deviations in most of loci of three species, and all diversity parameters suggested non-random mating in populations studied. The results in this study contribute to the knowledge of the genetic pool of the commercial tilapia species in Mexico. fish,genetic diversity,DNA markers,microsatellites http://www.journal-aquaticscience.com/article_73491.html http://www.journal-aquaticscience.com/article_73491_4bd140c382077f50b5d8a60c48e867f0.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Maturity Stages of Indian Mackerel Rastrelliger kanagurta (Cuvier, 1817) In Mayalibit Bay, Raja Ampat, West Papua 67 76 EN Dian Oktaviani Jatna Supriatna Mark Erdmann Abi Abinawanto Maturity stages of 3,485 individuals of the Indian mackerel Rastrelliger kanagurta (Cuvier, 1817) were measured from a population occurring in Mayalibit bay in Radja Ampat Regency of West Papua during the period of March 2011 through February 2012. Approximately 200-600 individuals were collected each month from the Warsambin and Lopintol villages, respectively,closed to the mouth of Mayalibit Bay. One thousand seven hundred and thirty four out of the 3485 individuals gonads (49.76%)were males and 1751 (50.24%) were females. The estimated length at first maturity values or Lm50 of male and female were at 19.55 cm and 20.71 cm, respectively, this significantly larger than populations examined in the Malacca Strait and Java Sea. In both sexes, individuals in all 5 maturity stages were recorded each month, with the highest cumulative percentage being stage IV (ripe gonads) for both males (50.4%) and females (38.8%). Weights of individual male testes ranged from 0.9 to 20.4 g, while female ovary weights ranged from 3.1 to 28.9 g. The result represents the heaviest ovaries that have not been recorded, yet for an individual of R. kanagurta. Two of the individuals examined showed hermaphroditic development. Forty among female ovaries specimens were at translucent stages which indicated the spawning periods of the species. This finding, along with the overall high percentage of individuals specimens at stage IV and V maturity, contribute a strong support to fisher knowledge and local fisheries office report that Mayalibit Bay may taken into considered as a spawning aggregation area for R. kanagurta. Rastrelliger kanagurta,maturity stages http://www.journal-aquaticscience.com/article_73492.html http://www.journal-aquaticscience.com/article_73492_866dd52ea9ecf89049d039df1bd5827c.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Aspects of the biology of blue crab Callinectes amnicola (DE Rocheburen, 1883) in Lagos lagoon, Nigeria 77 82 EN Fisayo Olakolu Oluwafemi Fakayode The length-weight relationship, condition factor and sex ratio of blue crab Callinectes amnicola from Lagos Lagoon, Lagos State, Nigeria were studied for a period of one year. Each crab was sorted into species, sex and the required metric measurements were taken. The carapace width and length were measured to the nearest millimetre (mm) while weight was measured to the nearest grams (g). The length-weight relationships of all samples collected were determined for the various sexes. The exponent ‘b’ values for all the sexes from the 3 stations significantly different (p<0.001) ranged from 2.170-2.928. The growth generally exhibited negatively allometry in all the sexes throughout the 3 stations. The condition factor (k) values were significantly different (p<0.001) ranged from 5.73-7.53.The “k” values of male crabs were higher than female crabs across the 3 stations. The sex ratios differ significantly from the expected 1:1 ratio; the female blue crabs were more abundance than males in all the stations, which suggests the stations to be breeding ground for crabs. Callinectes amnicola,Length-weight relationship,condition factor,sex ratio http://www.journal-aquaticscience.com/article_73493.html http://www.journal-aquaticscience.com/article_73493_356b69c73e933db9366b1310be091f4d.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Assessment of contamination by organochlorine pesticides in the Loukkos area (Morocco) 83 93 EN El Mustapha Daoudi Mohamed Fekhaoui Mohamed El Morhit Driss Zakarya Abdellah EL Abidi Boujmaa Daou Abdelmalek Dahchour This work is to assess the degree of contamination by organochlorine pesticides (OCP) in Loukkos area in the northwest of Morocco: 12 organochlorine pesticides including aldrin, DDT and its isomers (DDD and DDE), dieldrin, endrin, α endosulfan, heptachlor, heptachlor epoxide, hexachlorobenzene (HCB), α HCH and γ HCH were monitored. Results of this study showed a significant contamination by organochlorine pesticides in the drained Loukkos area. Heptachlor detected in seven monitoringstations (P1, P2, P3, P4, P5, AM.O.L, and AV.O.L) was the most dominant with concentrations ranging from 0.053 to 0.371 µg/L exceeding the limit recommended by WHO and EU standard (0.03 µg/L). DDT was detected only in one station among the seven stations sampled, his concentration in P4 was (0.268 µg/L) exceeding the limit recommended by EU standard (0.1 µg/L), while its metabolite DDE (pp') was detected on traces in P2 (0.016 µg/L), his presence could reflect previous use of DDT in the area. Lindane (γ HCH) was detected at traces in stations P1 (0.051 µg/L) and P2 (0,084 µg/L). Similarly dieldrin was detected in P2 at 0.067 µg/L. Since OCP were banned in 1984, contamination of the water in the region would be linked directly to the intensive use of the past before the ban in 1984, to the illegal use of some old stocks of these compounds or to eventual and also to ease the transition in sandy soils in the region. Organochlorine pesticides,Loukkos area,Morocco http://www.journal-aquaticscience.com/article_73494.html http://www.journal-aquaticscience.com/article_73494_e1aa4bdf7d73bd1da6c7d0fddfe94fe6.pdf

Int. J. of Aquatic Science 2008-8019 5 1 2014 01 01 Amphibian Chytridiomycosis: A threat to global biodiversity 94 109 EN Christian Arturo Aceves Hernández María del Carmen Monroy Dosta Aida Hamdan Partida José Alberto Ramírez Torres Jorge Castro Mejía Germán Castro Mejía Ramón De Lara Andrade Amphibians from all biogeographic regions of the world are faced with a significant decrease in their populations. Although the most common causes of this decline are undoubtedly the alteration and destruction of habitat, the influence of emerging diseases on species decline and extinction has also been shown in recent years. Such is the case of chytridiomycosis, an amphibian skin disease caused by the fungus Batrachochytrium dendrobatidis, which has drawn scientific attention as recent studies have attributed the extinction of more than 30 species in Latin America to its high pathogenicity and global distribution. In Mexico, the disease has already been identified in the Valley of Mexico and several states, such as Chiapas, Estado de Mexico, Puebla, Oaxaca, Michoacan, Morelos, Sonora.. Yet further studies are necessary to increase our understanding of the behavior of chytridiomycosis in the wild and captive populations. As such, this review paper aims to advance our knowledge of this pathogen, its distribution and its worldwide and local control strategies. Amphibians,Batrachochytrium dendrobatidis,Chytridiomycosis,Species conservation http://www.journal-aquaticscience.com/article_73495.html http://www.journal-aquaticscience.com/article_73495_53126701844ec82fd1006863192f7911.pdf