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Öğe Culture of the important crayfish species in Turkey(Ege Univ, 2006) Mazlum, Yavuz; Yilmaz, ErdalThere are 10 crayfish species cultured commonly throughout the world belong to Astacidae, Cambaridae, and Parastacidae families. While Astacidae and Cambaridae are cultured in the northern hemisphere, Parastacidae occurs in the southern hemishephere. Extensive culture techniques are used in crayfish culture mostly and semi-intensive and intensive methods are also performed. Global crayfish production through culture has been increased when compared to previous years. However, in our country, crayfish production decreased dramatically from 5000 to 200 tons after 1985 because of overfishing, pollution and crayfish plague (Aphanomyces astaci). To refresh our country's crayfish production potential, the present crayfish population need to be managed properly and determined the new crayfish species have high economic importance and reproductive traits to our country's conditions. Therefore, cultured crayfish species were examined with respect to their production and adaptation characteristics.Öğe Effect of dietary olive pomace oil and L-carnitine on growth and chemical compostion of African catfish, Clarias gariepinus (Burchell, 1822)(2004) Yilmaz, Erdal; Naz, Mehmet; Akyurt, IhsanThe effects of dietary olive pomace oil and L-carnitine on growth performance, body indices and chemical composition of African catfish, Clarias gariepinus, were investigated. A 3×2 factorial design was used by offering diets having three different energy/protein ratios and supplemental L-carnitine at either 0 or 2000 mg/kg diet. Ten juvenile African catfish (12 g/fish) were stocked into 80-1 glass aquaria and fed an experimental diet for seven weeks. The L-carnitine supplementation did not affect body indices. However, growth and chemical composition were influenced by both dietary lipid and L-carnitine. The increase in muscle lipid was greater than in the liver for all treatments. Fish fed the high energy diet (9% olive pomace oil) had a low appetite and feed intake, while fish fed the low energy diet (3% olive pomace oil) and supplemental L-carnitine had better feed intake and growth. On the other hand, fish fed the high energy diet (9% olive pomace oil) with or without L-carnitine had better feed conversion.Öğe The effect of stocking density on growth and survival of the freshwater mussel Unio tigridis (Bivalvia: Unionoidea)(2011) Şereflişan, Hlya; Yilmaz, ErdalThe effects of four stocking densities of 20, 40, 60, 80 mussels/m 2 on growth of Unio tigridis were investigated. The growth of the freshwater mussel U. tigridis in cages was studied for a year from March 2003 to April 2004 in Lake Gölbaş?. Juvenile mussels with the initial weight of 0.64 ± 0.08 g were stocked in metal cages placed on the lake bottom. Growth in live weight, shell length, width and height was measured monthly for the four different stock groups. Chlorophyll a, magnesium (Mg), nitrite (NO 2), nitrate (NO 3), amount of organic matters, ammonia (NH 3), phosphate (PO 4), silica (Si) and calcium (Ca) were also analyzed monthly. All water quality parameters were within proper limits for mussel culture. At the end of the study, the greatest live weight (5.55 ± 0.03 g) was obtained from 40 mussels/m 2, with 3.5 2 ± 0.02 cm and 1.47 ± 0.03 cm as length and width values, respectively. The greatest height was determined in a stocking rate of 60 mussels/m 2, with 1.99 ± 0.03 cm. Therefore, juveniles should be stocked in early spring for U. tigridis at a level of 4060 individuals/m 2.Öğe THE EFFECT OF STOCKING DENSITY ON GROWTH AND SURVIVAL OF THE FRESHWATER MUSSEL UNIO TIGRIDIS (BIVALVIA: UNIONOIDEA)(Inst Malacol, 2011) Sereflisan, Hulya; Yilmaz, ErdalThe effects of four stocking densities of 20, 40, 60, 80 mussels/m(2) on growth of Unio tigridis were investigated. The growth of the freshwater mussel U. tigridis in cages was studied for a year from March 2003 to April 2004 in Lake Golbasi. Juvenile mussels with the initial weight of 0.64 +/- 0.08 g were stocked in metal cages placed on the lake bottom. Growth in live weight, shell length, width and height was measured monthly for the four different stock groups. Chlorophyll a, magnesium (Mg), nitrite (NO2), nitrate (NO3), amount of organic matters, ammonia (NH3), phosphate (PO4), silica (Si) and calcium (Ca) were also analyzed monthly. All water quality parameters were within proper limits for mussel culture. At the end of the study, the greatest live weight (5.55 +/- 0.03 g) was obtained from 40 mussels/m(2), with 3.5 2 +/- 0.02 cm and 1.47 +/- 0.03 cm as length and width values, respectively. The greatest height was determined in a stocking rate of 60 mussels/m(2), with 1.99 +/- 0.03 cm. Therefore, juveniles should be stocked in early spring for U. tigridis at a level of 40-60 individuals/m(2).Öğe The effect of varying dietary energy on gonad development at first sexual maturity of the Sharptooth catfish (Clarias gariepinus Burchell, 1822)(Springer, 2009) Cek, Sehriban; Yilmaz, ErdalThe objective of this study was to investigate the effects of five isonitrogenous (35% crude protein) diets having different energy contents; 10.85, 11.82, 12.73, 13.69, and 15.06 MJ DE/kg, respectively, on the gonad development and weight gain of Sharptooth catfish fingerlings. Energy contents of the experimental diets were increased with the increasing amount of soy-acid oil (0, 4, 8.5, 13, 18%) and each group of fish was fed on their respective diets (group I was fed diet I) during 180 days. The gonad maturation was significantly affected by dietary energy. In both sexes, the histological inspections of the gonads did reveal differences among the fish fed different energetic diets. Fish fed diets I, II, and III had significantly heavier and more developed gonads compared to those on diets IV and V. Fish fed the higher energetic diets (IV and V) had partially low numbers of yolky oocytes compared to other groups. The mean GSI values of female and male fish fed with diet III was significantly greater than those fed diets with higher dietary energy; however, higher HSI values were recorded for fish fed with the higher energetic diets (IV and V). Also, the best weight gain for both males and females were recorded from the fish fed diet III (12.73 MJ DE/kg). Therefore, on the basis of the present results, among energy levels tested, 12.73 MJ DE/kg was found to be optimal for healthy gonad development and weight gain.Öğe The effects of combined phytoestrogen administration on growth performance, sex differentiation and body composition of sharp tooth catfish Clarias gariepinus (Burchell, 1822)(2009) Yilmaz, Erdal; Çek, Şehriban; Mazlum, YavuzThe present study was conducted to investigate the effects of Genesis (G, a commercial mixture of phytoestrogens) on growth, body composition and sex differentiation of Sharp tooth catfish Clarias gariepinus. Genesis is a commercially available product on USA and European markets used for menopausal complaints as an alternative medicine. Different concentrations (0 mg G 30 L -1, 210 mg G 30 L -1, 420 mg G 30 L -1, 630 mg G 30 L -1, 750 mg G 30 L -1 and 1500 mg G 30 L -1) of Genesis were administered by immersion of newly hatched larvae (averaging 2.27±0.12 mg) every 3 days for 30 days then immersion treatments were ceased and all groups reared in the same condition for the later 90 days, a total 120 days experimental period. At the end of the trial, specific growth rate of the females increased with the increasing concentration of Genesis up to 420 mg 30 L -1 (P<0.05), but different concentrations of Genesis did not affect the growth performance of males (P>0.05). The highest value of protein content (21.60%) was observed from the 420 mg G 30 L -1 group and found significantly different from the control and other groups (P<0.05). Also, lipid contents were significantly affected by the Genesis concentrations and the highest lipid contents were detected in the 210 mg G 30 L -1 (5.98%) and the 630 mg G 30 L -1 (6.66%) groups. Although among the dosages used in the present study, 1500 mg G 30 L -1 was the most effective dosage that ensured maximum female ratio (69.77%), the sex ratios observed for 0, 210, and 420 mg G 30 L -1 treatment groups were nearly the expected ratio of 1:1 (male: female). Therefore, it was concluded that usage of higher doses and treatment durations of Genesis could be more effective for all-female production of the Sharp tooth catfish population. © Central Fisheries Research Institute (CFRI) Trabzon, Turkey and Japan International Cooperation Agency (JICA).Öğe The Effects of Combined Phytoestrogen Administration on Growth Performance, Sex Differentiation and Body Composition of Sharptooth Catfish Clarias gariepinus (Burchell, 1822)(Central Fisheries Research Inst, 2009) Yilmaz, Erdal; Cek, Sehriban; Mazlum, YavuzThe present study was conducted to investigate the effects of Genesis (G, a commercial mixture of phytoestrogens) oil growth, body composition and sex differentiation of Sharptooth catfish Clarias gariepinus. Genesis is a commercially available product on USA and European markets used for menopausal complaints as an alternative medicine. Different concentrations (0 mg G 30 L(-1), 210 mg G 30 L(-1), 420 mg G 30 L(-1), 630 mg G 30 L(-1), 750 mg G 30 L(-1) and 1500 mg G 30 L(-1)) of Genesis were administered by immersion of newly hatched larvae (averaging 2.27+/-0.12 mg) every 3 days for 30 days then immersion treatments were ceased and all groups reared in the same condition for the later 90 days, a total 120 days experimental period. At the end of the trial, specific growth rate of the females increased with the increasing concentration of Genesis up to 420 mg 30 L(-1) (P<0.05), but different concentrations of Genesis did not affect the growth performance of males (P>0.05). The highest value of protein content (21.60%) was observed from the 420 mg G 30 L(-1) group and found significantly different front the control and other groups (P<0.05). Also, lipid contents were significantly affected by the Genesis concentrations and the highest lipid contents were detected in the 210 mg G 30 L(-1) (5.98%) and the 630 mg G 30 L(-1) (6.66%) groups. Although among the dosages used in the present study, 1500 mg G 30 L(-1) was the most effective dosage that ensured maximum female ratio (69.77%), the sex ratios observed for 0, 210, and 420 mg G 30 L(-1) treatment groups were nearly the expected ratio of 1: 1 (male: female). Therefore, it was concluded that usage of higher doses and treatment durations of Genesis could be more effective for all-female production of the Sharptooth catfish population.Öğe Effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of the hybrid Tilapia (Oreochromis niloticus x O-aureus)(Israeli Journal Of Aquaculture-Bamidgeh, 2007) Genc, M. Ayce; Yilmaz, Erdal; Genc, Ercument; Aktas, MevlutThis is the first study on the effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental diets were prepared from commercial trout diet, supplemented with MOS at levels of 0, 1.5, 3.0, or 4.5 g MOS/kg feed and randomly assigned to triplicate groups. At the end of the trial, there were no significant differences between treatment groups (p>0.05) in growth parameters (live weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio) or body indices (hepatosomatic and viscerosomatic). Dry matter and protein contents increased with increasing rates of dietary MOS (p<0.05) while the mean villi length of fish fed the diet containing 1.5 parts per thousand. MOS was significantly longer (p<0.05) than that of the fish fed 4.5%. dietary MOS. The different levels of dietary MOS had no detrimental effects on liver tissue or general fish health.Öğe Effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of the hybrid tilapia (Oreochromis niloticus x O. aureus)(2007) Genc, M. Ayce; Yilmaz, Erdal; Genc, Ercument; Aktas, MevlutThis is the first study on the effects of dietary mannan oligosaccharides (MOS) on growth, body composition, and intestine and liver histology of hybrid tilapia (Oreochromis niloticus x O. aureus). Experimental diets were prepared from commercial trout diet, supplemented with MOS at levels of 0, 1.5, 3.0, or 4.5 g MOS/kg feed and randomly assigned to triplicate groups. At the end of the trial, there were no significant differences between treatment groups (p>0.05) in growth parameters (live weight gain, specific growth rate, feed conversion ratio, protein efficiency ratio) or body indices (hepatosomatic and viscerosomatic). Dry matter and protein contents increased with increasing rates of dietary MOS (p<0.05) while the mean villi length of fish fed the diet containing 1.5%. MOS was significantly longer (p<0.05) than that of the fish fed 4.5‰ dietary MOS. The different levels of dietary MOS had no detrimental effects on liver tissue or general fish health.Öğe Effects of dietary mannan oligosaccharides on growth, body composition, and intestine and liver histology of rainbow trout, Oncorhynchus mykiss(Israeli Journal Of Aquaculture-Bamidgeh, 2007) Yilmaz, Erdal; Genc, M. Ayce; Genc, ErcumentThis study investigated the effects of dietary mannan oligosaccharicles (MOS) on growth, body composition, and small intestine and liver histology of rainbow trout (Oncorhynchus mykiss Walbaum). Experimental diets were supplemented with 0 (control), 1.5, 3.0, or 4.5 g MOS per kg commercial trout feed and randomly assigned to treatment groups. Enhanced growth performance was generally observed in fish fed the diet supplemented with 1.5 parts per thousand MOS. Villi of fish fed diets supplemented with 1.5 or 3.0 parts per thousand MOS were longer than those of fish fed 4.5 parts per thousand or no dietary MOS (p<0.05). Protein contents increased as the rate of MOS increased (p<0.05). There were no significant differences in feed conversion ratio, protein efficiency ratio, or hepatosomatic index (p>0.05) and MOS had no detrimental effects on the intestine.Öğe Effects of dietary Mannan-oligosaccharide on growth, intestine and liver histology of the African catfish (Clarias gariepinus (Burchell, 1822))(Ege Univ, Fac Fisheries, 2006) Genc, M. Ayce; Yilmaz, Erdal; Genc, ErcumentDifferent levels of dietary mannan-oligosaccharide (MOS) administered for 80 days to African catfish (Clarias gariepinus) were evaluated for their efficacy on growth parameters, and intestine and liver histology. The following levels of MOS were used in commercial trout diet: 1%, 2% and 3% during the trial. At the end of the feeding period the live body weight gain and feed conversion ratio, hepatosomatic and gonadosomatic index values were found similar for all experimental groups (P>0.05). Also, dietary MOS did not significantly affect the liver and intestine histology.Öğe Effects of energetic diets on growth, blood chemistry, and liver pathology of African catfish, Clarias gariepinus (Burchell 1822)(Society Of Israeli Aquaculture & Marine Biotechnology, 2006) Yilmaz, Erdal; Akyurt, Ihsan; Mutlu, EkremThe effects of isonitrogenous diets (350 g crude protein/kg diet) with different energy levels (10.85, 11.82, 12.73, 13.69, and 15.06 MJ dietary energy/kg feed) on growth, feed utilization, blood chemistry, and liver histopathology of African catfish, Clarias gariepinus, were investigated to determine the optimum diet for this species. The diet containing 12.73 MJ digestible energy/kg feed resulted in the best growth, blood parameters, and liver histology. Fish that consumed the 10.85 and 11.82 diets had similar weight gains, feed, and protein utilization as fish fed diets containing 13.69 or 15.06 MJ (p > 0.05) but fish fed diets containing 13.69 or 15.06 MJ/kg had signs of hepatic lipidosis.Öğe Offshore Farming of the Mediterranean Amberjack (Seriola dumerili) in the Northeastern Mediterranean(Israeli Journal Of Aquaculture-Bamidgeh, 2011) Yilmaz, Erdal; Sereflisan, HulyaThe growth rate, survival, and feeding parameters of Mediterranean amberjack (Seriola dumerili Risso, 1810) cultivated in offshore cages in the Gulf of Iskenderun (Hatay, Turkey) were investigated from July 2006 to March 2008. Two offshore cages (339 m(3)) were placed at a depth of 10 m in a sheltered area 500 m off the coast. Juveniles (101.97 +/- 14.54 g), caught with seine nets 400-1200 m from the coast, were stocked in the cages at 250 per cage. Fish in one cage, Group A, were fed commercial pellets for all 20 months whilst fish in the second cage, Group B, were fed pellets for the first 16 months and frozen sardines for the following four. The mean live weight, survival, feed conversion ratio, daily feed consumption, and water quality parameters were recorded monthly. Group B reached a significantly (p < 0.05) greater weight (2785.00 +/- 64.91 g) than Group A (2441.14 +/- 38.13 g). Food conversion ratios ranged 1.16-2.46 for group A and 1.10-2.28 for group B, low when compared with other studies on amberjacks in the Mediterranean. Average mortality was 25%, due to a Zeuxapta seriolae (Monogenea: Heteraxinidae) infection in December 2006 (20%) and fish handling for measurement in June 2007 (similar to 5%). The farmed amberjacks had significantly higher protein and lipid contents than their wild counterparts at the end of the 20-month feeding period. Amberjacks found frozen sardines more appealing than pellets, especially during the winter. In conclusion, it is advised to feed Mediterranean amberjack frozen sardines or other trash fish during the winter grow-out period. Their rapid growth rate, as well as their adaptability to farming, make offshore net cages a promising system for the aquaculture of this species.Öğe A preliminary study on the use of mannan oligosaccharides (MOS) in freshwater crayfish, Astacus leptodactylus Eschscholtz, 1823 juvenile diets(Springer, 2011) Mazlum, Yavuz; Yilmaz, Erdal; Genc, M. A.; Guner, OzlemThe effects of dietary mannan oligosaccharides (MOS) on the survival and growth of Astacus leptodactylus juveniles were evaluated. Experimental diets were prepared by using supplementation of 0 (Control), 1.5, 3.0, and 4.5 g MOS kg(-1) commercial trout larvae diet containing 43 g kg(-1) protein and 15.74 g kg(-1) lipid. A. leptodactylus juvenile with an average total length of 3.6 +/- 0.46 cm (TL) and average weight of 1.25 +/- 0.43 g was stocked in 0.2-m(2) aquariums at a rate of 50 crayfish/m(2) and reared for 60 days at 22.8 degrees C. The experiment consisted of four treatments with three replicates each. Each aquarium contained ten crayfish. Crayfish juvenile fed with 0, 1.5, 3.0, and 4.5 MOS attained 6.15 +/- 0.49, 5.94 +/- 0.29, 7.34 +/- 0.39, and 5.94 +/- 0.27 cm final total length and 50, 56.67, 46.67, and 50% survival rates, respectively. Moreover, molting frequencies in 0, 1.5, 3.0, and 4.5 g kg(-1) MOS groups were detected as 44.44, 61.11, 83.33, and 38.88%, respectively. At the end of the experiment, a general enhanced growth performance (P < 0.05) and feed conversion ratio were observed in crayfish fed on the diet containing 3.0 g kg(-1). Crayfish juveniles fed with 3.0 g kg(-1) MOS had the highest final length (7.34 +/- 0.39 cm), although their survival was the lowest (46.67%) compared to other treatments but not significant. Specific growth rates were significantly different (P < 0.05) among the treatment groups at the end of the 60-day experiment. There were no significant differences (P > 0.05) in percentage moisture, protein, and ash (wet-weight basis) in the tail meat of A. leptodactylus juvenile among treatments (diet) that averaged 82.3, 16.1, and 1.2%, respectively. However, lipid value was significantly different among the diets P < 0.05), with values between 0.13 and 0.32. From the current results, it could be advised to use MOS at the rate of 3.0 g kg(-1) in A. leptodactylus juvenile diets.Öğe Prey selection by African catfish Clarias gariepinus(Burchell, 1822) larvae fed different feeding regimes(2006) Yilmaz, Erdal; Bozkurt, Ahmet; Gökçek, KayaLive prey selection by African catfish, Clarias gariepinus, larvae was examined under laboratory conditions. Larvae were offered plankton, plankton + trout starter (TS) and plankton + betaine supplemented trout diet (BTS) for 7 days after exogenous feeding. Five larvae were sampled to determine their gut contents and selectivity index for each treatment 15 min after the feeding. It was observed that dry diets (TS and BTS) improved the growth (P < 0.05), but did not significantly influence the prey selection of the larvae. It was determined that African catfish larvae preferred Copepods and Rotaria sp. to other zooplankton species for all feeding regimes. © TÜBİTAK.
