IJA Volume 57, Issue 2, 2005

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    Embryonic and larval development of striped sea bream (Lithognathus mormyrus L 1758)
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Firat, Kursat ; Saka, Sahin ; Kamaci, H. Okan
    Development of the embryonic and yolk-sac larvae of striped sea bream (Lithognathus mormyrus) was investigated. The average egg and oil globule diameters were 0.71±0.1286 mm and 0.18±0.1344 mm, respectively. The morula, gastrula, and neurula stages, somite formation, and hatching occurred 2:10, 5:15, 8:45, 9:45, and 21:15 hours after fertilization. The total length, yolk- sac volume, oil globule volume, digestive tube length, otolith diameter, head length, eye diameter, preanal and postanal lengths of newly hatched larvae were 1.74±0.03 mm, 0.12±0.008 mm3, 0.003±0.0002 mm3, 0.47±0.02 mm, 54±8 μm, 299±11 μm, 157±8 μm, 911±0.3 μm, and 827±0.03 μm. When the mouth opened 40 h after hatching, these measurements were 2.87±0.014 mm, 0.003±0.001 mm3, 0.001±0.0001 mm3, 0.61±0.015 mm, 134±8 μm, 376±10 μm, 221±13 μm, 1.02±0.03 mm, and 1.84±0.03 mm. During the first 18 hours, the larvae reached 84% of its final total length, the yolk sac was 65% absorbed, and the oil globule was 62% absorbed. Statistical analysis showed negative allometry for the relationships between total length and yolk-sac volume (r2 = 0.88) and total length and oil globule volume (r2 = 0.76), and positive allometry for the relation- ship between total length and digestive tube length (r2 = 0.89).
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    Effect of freezing techniques, extenders and cryoprotectants on the fertilization rate of frozen rainbow trout (Oncorhynchus mykiss) sperm
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Bozkurt, Yusuf ; Akcay, Ergun ; Tekin, Necmettin ; Secer, Selçuk
    Rainbow trout (Oncorhynchus mykiss) sperm was frozen in liquid nitrogen in straws or as pellets on dry ice and stored in liquid nitrogen until artificial insemination. Sperm was diluted with one of three extenders containing 15% DMSO or 15% DMA as a cryoprotectant at a ratio of one part sperm to two parts extender. The straws were thawed in a water bath while the frozen pellets were thawed in their own extenders at 30oC for 30 s. For both freezing methods, the best fertil- ization results were obtained with extender III containing 15% DMSO, 52.3% (56.3% of the con- trol) for sperm frozen in straws and 48.4% (52.4% of the control) for sperm frozen as pellets. The interaction between extender and cryoprotectant was statistically significant (p<0.05).
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    Management induced changes in food selection, growthandsurvivalofkoicarp,Cyprinuscarpiovar.koi l.,Intropicalponds
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Jha, Prithwiraj ; Barat, Sudip
    The effects of different management regimes on the feeding habits and food selection of koi carp (Cyprinus carpio var. koi L.) larvae were examined. Weight gain, fish deformities, and survival were compared in an 11-week growth trial conducted in tropical ponds maintained according to four culture regimes: (1) live food system; (2) poultry manure treated system; (3) cow dung treat- ed system; and (4) a control. The Ivlev’s Electivity Index showed that koi larvae avoided phyto- plankton and preferred cladocerans, an important source of natural food in all the regimes. In the poultry and cow manured ponds, the larvae were negatively elective towards copepods although they were more abundant than cladocerans. Weight gain and survival was significantly higher in the live-feed system (p<0.05) than in the other systems. Fish deformities were significantly high- er (p<0.05) in the control.
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    Effect of temperature on embryonic development in sharpsnout seabream (Diplodus puntazzo) eggs
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Firat, Kursat ; Saka, Sahin ; Özden, Osman
    Embryonic development of sharpsnout seabream (Diplodus puntazzo) was studied at eleven water temperatures (two degree intervals from 12 to 32°C). Embryos successfully developed at temperatures of 16-28°C. Cells did not divide at the temperature extremes of 12 and 32°C. Total mortality was observed by the 128 cleavage stage at 14°C and all eggs were dead by the time the embryos extended 2/3 of the internal circumference of the egg at 30°C. There was an inverse relationship between incubation temperature and the rate of embryonic development.
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    Prevalence and intensity of Hexamita salmonis in rainbow trout farms in the southeastern Black Sea and their relationship to environmental factors
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Ogut, Hamdi ; Akyol, Abdurrezzak
    An acute rise of unexplained mortalities (reaching 84,000 fish at one farm in 2002, 32%) was observed at a rainbow trout (Oncorhynchus mykiss) farm on the southeastern Black Sea coast from January to June for at least the last four years. Three rainbow trout farms on the same river system were surveyed for eight months to determine the occurrence and spread of the suspect- ed causative agent, Hexamita salmonis. We found that this protozoan was endemic to the trout farms from December through late August. The main determinants of the incidence and intensi- ty were water temperature (non-linear regression, r 2 = 0.77) and oxygen and nitrate levels (ANOVA, r2 = 0.83). The mean intensity of the parasite gradually decreased while prevalence gradually increased from February to April at the farm with the highest values. There was no weight loss in infected fish compared to uninfected fish (p = 0.4). The downstream farm had a higher level of parasitic intensity than the upstream farm during the high risk season. Hexamitiasis was the main cause of the high mortality in May and June when water tempera- tures were around 6-13oC. Prophylactic measures should be taken in systems where this para- site is endemic. This is the first report of hexamitiasis from Turkey.
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    Effects of dietary fish oil, soy-acid oil, and yellow grease on growth and hepatic lipidosis of hybrid tilapia fry
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Genc, Ercument ; Yilmaz, Erdal ; Akyurt, Ihsan
    The objective of this study was to compare the effects of dietary lipids on growth and liver histopathology of hybrid tilapia, Oreochromis niloticus x O. aureus, fry (6.0 g). Fish were fed one of six diets containing 8.4% fish oil (control), 8.4% soy-acid oil, 8.4% yellow grease, 5.6% yellow grease plus 2.8% soy-acid oil, 2.8% yellow grease plus 4.6% soy-acid oil, or 4.2% soy-acid oil plus 4.2% yellow grease for 60 days. Growth was similar in all groups and retarded in compari- son to earlier studies. Lipid accumulation as well as microvesicular (foamy degeneration) and macrovesicular degeneration in the liver were histopathologically detected.
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    Use of geographic information system (GIS) to select fish cage farming sites in Surmene Bay, Black Sea
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Guneroglu, Abdulaziz ; Kose, Ercan ; Eruz, Coskun ; Basar, Ersan ; Erkebay, Sebnem
    Attempts to develop open sea fish farming projects in the Black Sea have often failed due to poor site selection. This problem can be solved by using the Geographic Information System (GIS) to collect, manipulate, query, display, and integrate various data sets. In this study, data sets were arranged together to analyze habitats and a site selection methodology was developed for the coastal region of Trabzon on the Surmene Bay. Data included temperature, salinity, and current velocity, collected during regular cruises of the KTU-R/V Denar-I research vessel. Shoreline data were digitized using regional maps and spatial relationships were examined using Boolean Algebra. Two interpolation methods (Kriging and Inverse Distance Weight) were used to form thematic maps and identify optimal sites for a rainbow trout cage farm. No significant differences were found between the results of the two methods. Temperature was the most influential fac- tor determining the final site position.
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    Screening of desert plants for use against bacterial pathogens in fish
    (Israeli Journal of Aquaculture - BAMIGDEH, 2005) Abutbul, S. ; Golan-Goldhirsh, A. ; Barazani, O. ; Ofir, R. ; Zilberg, D.
    The antibacterial activity of aqueous extracts of 104 desert plant species was studied on the fol- lowing fish bacterial pathogens: Aeromonas hydrophila, Photobacterium damselae subspecies piscicida, Streptococcus iniae, and Vibrio alginolyticus. Seventeen plant species had antibacte- rial activity, as identified by disk diffusion assay. The pathogen P. damselae was sensitive to all 17 active extracts except Peganum harmala and a high inhibitory effect (14-19.5 mm) was pro- duced by Anchusa strigosa, Hammada scoparia, Achillea fragrantissima, Pulicaria crispa and Loranthus acaciae. The pathogens A. hydrophila and V. alginolyticus were inhibited by H. sco- paria, L. acaciae, and P. harmala (7-20.5 mm). The pathogen S. iniae was inhibited by Ochradenus baccatus and Reseda stenostachya (10.5 mm). The benefits of using desert plants as an alternative to conventional antibiotics are discussed.