Bafra balık gölleri`nden Ulugöl`de tatlısu ıstakozu (Astacus leptodactylus Eschscholtz, 1823)`nun bazı populasyon parametrelerinin belirlenmesi

Abstract

Arastırmada Bafra Ulugöl'den Temmuz 2010-Temmuz 2011 tarihleri arasında toplam 378 adet kerevit örneklenmistir. Kerevitlerin biyometrik ölçümleri yapılmıs,yumurta, et verimi, hastalık ve anomalilere iliskin veriler toplanmıstır. Mevcut çalısmada toplam 378 adet kerevitin 198 adedi disi, 180 adedinin ise erkek oldugu veaylara göre cinsiyet oranları arasındaki farkın önemsiz oldugu belirlenmistir (p>0.05).Kerevitlerin boy dagılımı incelenmis ve sefalotoraks boyu 22-83 mm toplam boy 80-156 mm aralıgında dagılım göstermistir. Ortalama sefalotoraks boyu disilerde50.96±0.46 mm, erkeklerde 51.31±0.66 mm ve tüm kerevitlerde 51.13±0.40 mm olarak bulunmustur. Abdomen uzunluk ortalaması disilerde 52.36±0.49 mm, erkeklerde 49.26±0.62 mm ve tüm bireylerde 50.87±0.40 mm olarak belirlenmistir. Disi kerevitlerin abdomenlerinin erkek kerevitlerden daha genis oldugu belirlenmistir (p<0.05). Bununla beraber, erkek kerevitlerin sefalotoraks uzunlugu, kıskaç uzunlugu,kıskaç genisligi daha yüksek bulunmustur (p<0.001). Avlanılan kerevitlerin agırlıkları incelendiginde canlı agırlıgın 14.38 g ile 105.03 g arasında degistigi ve ortalama agırlıgın 38.26±0.73 g oldugu saptanmıstır. Disilerin ortalama agırlıgı 35.63±0.73 g,erkeklerin ortalama agırlıklarından 41.12±1.27 g daha düsük bulunmustur (p<0.05).Boy ile agırlık arasında kuvvetli bir dogrusal iliski bulunmustur (r=0.91).Örneklenen yumurtalı kerevitlerin minimum 28.24 g, maksimum 59.50 g veortalama 41.73±1.09 g agırlıga sahip oldugu belirlenmistir. Yumurtalı kerevitlerin bireysel ortalama yumurta sayısının 192.90±9.94 adet oldugu, maksimum 368,minimum ise 50 adet yumurta tasıdıkları tespit edilmis olup, birim agırlıga (1 g) düsen yumurta sayısı 4.62±0.21 adet olarak hesaplanmıstır. Toplam yumurta agırlıgının ortalama 3.35±0.19 g ve yumurtanın çapı ortalama 2.17±0.03 mm olarak tespit edilmistir. Abdomen eti miktarı erkek kerevitlerde 3.49±0.14 g, disi kerevitlerden3.59±0.13 g daha düsük bulunmustur. Çalısmada kerevitlerin abdomen etinde %81.27 nem, %1.47 ham kül, %0.81 ham yag ve %16.45 ham protein olarak tespit edilmistir.Anahtar Kelimeler: Tatlısu ıstakozu, Astacus leptodactylus, Ulugöl,Morfometrik analiz, Et verimi, Yumurta verimliligi

In this study, total 378 crayfish were sampled from Bafra Ulugöl between July 2010 and July 2011. Biometric measurements were done such as eggs, meat efficiency, disease and anomalies. In this research, total 398 of crayfish, were examined 198 femaleand 180 male individual identified and the monthly difference between sex ratios were insignificant (p>0.05). Length frequency distribution of crayfish were examined and cephalothorax length was 22-83 mm, total length was 80-156 mm. Average cephalothorax length was 50.96±0.46 mm for female, 51.31±0.66 mm for male and51.13±0.40 mm for all individuals. Average abdomen length was 52.36±0.49 mm for female, 49.26±0.62 mm for male and 50.87±0.40 mm for all individuals. The width of female crayfish abdomens was larger than male crayfish abdomens (p<0.05). However,male crayfish?s cephalothorax length, nipper length and nipper width were greater than female crayfish (p<0.001). Live body weight was varied between 14.38 g and 105.03 g,and average weight was 38.26±0.73 g, respectively. The average weights of female 35.63±0.73 g were lower than average weights of male 41.12±1.27 g (p<0.05). There was a strong linear correlation between height and weight (r =0.91).The minimum weight of egged crayfish was 28.24 g, maximum weight of egged crayfish was 59.50 g and average weight of egged crayfish was 41.73±1.09 g. The crayfish with eggs had average 192.90±9.94 units per individual eggs of with, maximum number of eggs were 368, minimum number of eggs were 50 carried, in the unit weight (1 g) calculated the number of eggs per 4.62±0.21 units. Total weight peregg was 3.35±0.19 g and average egg diameter was 2.17±0.03 mm, respectively. The amount of male crayfish abdomen flesh 3.49±0.14 g have been found significantly lower than female crayfish abdomen flesh 3.59±0.13 g. Crayfish abdomen meat,included 81.27% moisture, 1.47% crude ash, 0.81% crude fat and 16.45% crude protein.Keywords: Crayfish, Astacus leptodactylus, Ulugöl, Morphometric analysis,Meat yield, Efficiency of egg