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Öğe Estimating the population size of Astacus leptodactylus (Decapoda: Astacidae) by mark-recapture technique in E?irdir lake, Turkey(2011) Bolat, Yildiz; Mazlum, Yavuz; Demirci, Aydin; Koca, Habil U?urThe mark-recapture technique for closed populations was employed to estimate the population size and density of Astacus leptodactylus during August and September, 2005 by using minnow traps of 34 mm mesh size in E?irdir Lake. A total of 600 minnow traps were set randomly along the shoreline at approximately 3, 5 and 7 m depth. The nets were set in the late afternoon to each study depths, and were hauled the next day or after two days. The research was performed two times each month. In August, 1956 adult crayfish and in September, 2756 adult crayfish were marked by cauterization of the carapace. The recapture rates were found to be 3.5% in August and 2.3% in September, respectively. A total of 200 crayfish were randomly selected, 74 females and 126 males. The sex ratio was 1:1.7. Moreover, length and weight data gotten from 200 untagged crayfish showed that females and males differed significantly in their weight, but no significant difference was evident in the carapace length. From the mark-recapture experiment, it was estimated that catchable population size ranged between 32590 and 73503 individuals (with carapace length above 45 mm). Estimated density ranged between 0.54 and 1.2 individuals per m2. Recapture rates did not differ statistically among occasions. Despite the moderate and fluctuated growth in the crayfish population, catchable population should be estimated for each region in the lake by using the estimation methods. © 2011 Academic Journals.Öğe Estimating the population size of Astacus leptodactylus (Decapoda: Astacidae) by mark-recapture technique in Egirdir lake, Turkey(Academic Journals, 2011) Bolat, Yildiz; Mazlum, Yavuz; Demirci, Aydin; Koca, Habil UgurThe mark-recapture technique for closed populations was employed to estimate the population size and density of Astacus leptodactylus during August and September, 2005 by using minnow traps of 34 mm mesh size in Egirdir Lake. A total of 600 minnow traps were set randomly along the shoreline at approximately 3, 5 and 7 m depth. The nets were set in the late afternoon to each study depths, and were hauled the next day or after two days. The research was performed two times each month. In August, 1956 adult crayfish and in September, 2756 adult crayfish were marked by cauterization of the carapace. The recapture rates were found to be 3.5% in August and 2.3% in September, respectively. A total of 200 crayfish were randomly selected, 74 females and 126 males. The sex ratio was 1:1.7. Moreover, length and weight data gotten from 200 untagged crayfish showed that females and males differed significantly in their weight, but no significant difference was evident in the carapace length. From the mark-recapture experiment, it was estimated that catchable population size ranged between 32590 and 73503 individuals (with carapace length above 45 mm). Estimated density ranged between 0.54 and 1.2 individuals per m(2). Recapture rates did not differ statistically among occasions. Despite the moderate and fluctuated growth in the crayfish population, catchable population should be estimated for each region in the lake by using the estimation methods.Öğe The evaluation of a red shrimp Plesionika martia (Decapoda: Pandalidae) in North-East Mediterranean Trawl Fishery(Ege Univ, 2007) Demirci, AydinThe aim of this study is to provide information on the fishing pattern of Plesionika martia in the North-East Mediterranean. Data were obtained from commercial fishery, covering the period May 2005-September 2005. According to sex and size, this species occur in deep waters and compose a significant by-catch or discard of deep-water trawl fisheries in the region. Evaluation of the deep water shrimp was four type in the demersal fishery, their type and catch per unit efficiency; by unmixed, 9.87 (+/- 3.41) kg(-1day), mixed with deep sea rose shrimp (Parapenaeus longirostris), 2.37 (+/- 1.14) kg(-1day), mixed with red shrimps (Aristaeomorpha foliacea ve Aristeus antennatus), 1.2 (+/- 0.12) kg(-1day) and by discard 0.4 (+/- 0.21) kg(-1day).Öğe Larval rearing of african catfish (Clarias gariepinus) using european pine sawfly (Neodiprion sertifer) larvae as direct food(Ege Univ, 2006) Genc, M. Ayce; Turan, Funda; Akyurt, Ihsan; Gokcek, Kaya; Demirci, Aydin; Gurlek, MevlutThe objective of this study was to compare the effects of different alternative (locally available) diets and their combination on growth of African catfish, Clarias gariepinus larvae. Fish larvae (mean weigth 2.70 +/- 0.08 mg, mean lenght 0.75 +/- 0.05 mm and 2 days old) were fed one of five diets containing commercial trout starter diet (TY as control diet), tubifex, European pine sawfly (Neodiprion sertifer: CAT) larvae, tubifex plus TY and CAT plus TY for 18 days. Growth was nearly similar in TY, Tubifex and CAT + TY groups and typically, retardation was detected especially in CAT group. On day 6, 10, 14 and 18 mean weight of the larvae varied significantly (p > 0.05) between the treatments. The results of this feeding trial showed that, the tubifex supplementation was (improve the efficiency of dry diet, TY) significantly improve the growth and survival rates (p < 0.05) and it is advisable than the other diets of this experiment.Öğe A preliminary study on population structure and abundance of Plesionika martia (A. Milne-Edwards, 1883) (Decapoda : Pandalidae) in the deepwater of the northeastern Mediterranean(Ege Univ, 2006) Can, M. Fatih; Aktas, Mevlut; Demirci, AydinThis study was conducted between 12 and 13 June 2004 in the deep waters of the northeastern Mediterranean Sea. A commercial trawl vessel was used and total 6 hauls were done to get some preliminary information on the population structure and abundance of red shrimp, Plesionika martia (A. MilneEdwards, 1883). A total of 50 specimens were sampled. The overall sex ratio, 1 male : 6.14 female, was significantly biased towards females (p<0.05). The mean carapace length (CL +/- SD) and mean weight (W +/- SD) of males and females were calculated as 59.28 +/- 14.49 mm (43-77 mm), 7.58 +/- 3.16 g (4.16-11.73 g), 73.62 +/- 9.24 mm (44-87 mm) and 12.13 +/- 3.88 g (4.5-19,7 g), respectively. Significant differences were detected between mean carapace length and weight of males and females (p<0.05). The ratios of red shrimp in the total catch and in the total shrimp catch were calculated as 5.53 % and 6.84 %, respectively. P. martia specimen were observed in the three out of six hauls. The catch per unit effort in the third haul was 4.5 kg/h, in the forth hauls was 2 specimen/h, and in the fifth haul was 2 specimen/h.Öğe Temporal Variability in Abundance of Demersal Fish Community from Izmir Bay, Turkey(Medwell Online, 2009) Can, M. Fatih; Tosunoglu, Zafer; Ozaydin, Okan; Demirci, Aydin; Guder, H. Salih; Aydin, Celalettin; Leblebici, SemihTemporal variabilities of demersal fish species were analaysed in terms of their numerical abundance in the Izmir Bay. A total of 545559 specimen belonging to eight different families were caught in 2005, covering all the year using a R/V trawl. The contribution of each family was Sparidae (34.38%), Serranidae (22.25%), Bothidae (15.09%), Mullidae (14.22%), Gobidae (3.71%), Centracanthidae (1.01%) and Uranoscopidae (0.28%). Based on temporal variabilities of the families, cluster analysis identified three main groups, which were group-I: the Mullidae, group-II: the Centracanthidae, Uranoscopidae, Bothidae, Gobidae and Serranidae and finally group-III: the Sparidae and Triglidae. The family belonging to the first group was more abundant in cold months (picked in January) than others. The second group were more yielded in general from June-October (picked in October). The third group were more abundant in May and June.
