Karakaya Baraj Gölü (Malatya)'nde Yaşayan Leuciscus cephalus Populasyonunun (L., 1758) 'un Bazı Biyolojik Özellikleri

The sex distribution, growth in length and weight, growth rates and condition factors of Chub (Leuciscus cephalus (L., 1758)) in Karakaya dam lake were examined. Females made up 63.64% and males 36.37% (1.75:1) of 527 samples. The females and males were in the I-VI and I-V age groups, respectively. The reproductive properties of L. cephalus such as spawning period, age at attainment of maturity, egg diameter and ovarium weight were investigated. StudentÕs t test showed that differences in length and weight between females and males of the same age groups were statistically insignificant (P > 0.05). The growth, both in length and weight, was calculated according to the von Bertalanffy equation for females and males respectively: Lt = 37.8 [1-e-0.4125(t-(-1.0013))], Wt = 775.3 [1-e-0.4125(t-(-1.0013))]3.0272 and Lt = 35.45 [1-e-0.6062(t-(-0.1883))], Wt = 590.5 [1-e-0.6062(t-(-0.1883))]2.4878. The calculated length-weight relation for females was W = 0.013 L 3.0272 and for males W = 0.0824 L2.4878. The average condition factor was 1.42 ± 0.05 for females and 1.43 ± 0.25 for males. According to gonado-somatic index (IG) results and the development of egg diameter, it was determined that the spawning period of L. cephalus occurs in May and June. Sexual maturity was attained in the third year. The mean diameter of ripe eggs was 1.06 mm and the mean number of eggs per gram of gonads was 1265.Karakaya Baraj G l Õnde yaßayan Leuciscus cephalus (L., 1758) populasyonuna ait 527 adet balÝk rneÛi, b y me ve reme zelliklerinin araßtÝrÝlmasÝ amacÝ ile aylÝk periyotlarla incelendi. Bu alÝßmada adÝ ge en t r n yaß kompozisyonu ve eßey daÛÝlÝmÝ, yaß Ð boy, yaß Ð aÛÝrlÝk, boy Ð aÛÝrlÝk ilißkileri, kondisyon fakt r ve reme ile ilgili bazÝ temel biyolojik zellikleri ( reme peryodu, reme yaßÝ ve yumurta verimliliÛi) saptandÝ. Üncelenen rneklerin % 63,64Õ dißi, ve % 36,37Õsi ise erkek bireylerden olußmaktadÝr. Dißiler I-VI, erkekler ise I-V yaß gruplarÝ arasÝnda bir daÛÝlÝm g stermektedir Erkek ve dißi bireyler arasÝnda ortalama boylar ve ortalama aÛÝrlÝklar farkÝnÝn Student-t testine g re nemsiz olduÛu bulunmußtur (P > 0,05). von Bertalanffy b y me denklemlerine g re yaß - boy, yaß - aÛÝrlÝk ilißkileri dißilerde ve erkeklerde sÝrasÝ ile; Lt = 37,8 [1-e-0,4125(t-(-1,0013))], Wt = 775,3 [1-e-0,4125(t-(-1,0013))]3,0272 ve Lt = 35,45[1-e-0,6062(t-(-0,1883))], Wt = 590,5 [1-e-0,6062(t-(-0,1883))]2,4878 dir. Boy Ð aÛÝrlÝk ilißkisi dißilerde W = 0,013 L 3,0272 ve erkeklerde W = 0,0824 L2,4878 olarak hesaplandÝ. Kondisyon fakt r dißilerde 1,53 ± 0,05 ve erkeklerde 1,42 ± 0,25 olarak bulunmußtur. Gonadosomatik indeks (IG) ve yumurta apÝnÝn gelißmesinden yararlanarak, bu t r n reme periyodunun MayÝs Ð Temmuz aylarÝ, ilk eßeysel olgunluk yaßÝnÝn III olduÛu bulundu. Tesad fen se ilen olgun yumurtalarÝn apÝ 1,06 mm, yumurta sayÝsÝ ise bir gramda ortalama 1265 olarak tesbit edildi