Endemik bir balık türü olan Aphanius villwocki`nin Özdere (Sakarya Nehri havzası ) populasyonunun büyüme ve üreme özellikleri

Abstract

Anadolu'nun bilinen en eski ikincil tatlısu balıklarından biri olarak kabul edilen, Cyprinodontidae familyasına ait Aphanius cinsi, Türkiye'de 9 tür ile temsil edilmektedir. Sunulan çalışmada, bugüne kadar biyolojisi hakkında hiçbir bilgi bulunmayan, Yukarı Sakarya Havzası' na endemik bir balık türü olan Aphanius villwocki' nin Özdere (Polatlı-Ankara) populasyonunun üreme ve büyüme özellikleri incelenmiştir. Bu kapsamda Haziran 2012-Temmuzişmektedir. Fekondite ile total boy, ağırlık, gonad ağırlığı ve yaş arasındaki ilişkiler belirlenmiş ve en kuvvetli ilişkinin fekondite ile yaş arasında olduğu saptanmıştır. Fekondite ile yaş ilişkisi denklemi F=171,58(t)1,0666 (R² = 0,907)'dir.

Aphanius, which belongs to Cyprinodontidae family, has been accepted as one of the oldest secondary fresh water fish in Anatolia that is represented by 9 different species in Turkey. In the presented study, growth and reproduction properties of Aphanius villwocki population in the Özdere (Polatlı-Ankara) were analyzed. This presented study is the first study on biology of Aphanius villwocki, a species of Aphanius which is endemic in Upper Sakarya River Basin. Under these circumstances, field studies were conducted in monthly basis between June 2012 – July 2013 and in total, 1793 individuals were collected and their sex were determined, 718 of this sample were dissected and their gonads were removed and weighted. The distribution of length, weight, age and sex, length-weight, age- length, age-weight relationships, condition factor of the population and the von Bertalanffy growth parameters of the specimens were examined. It was determined that females were distributed over 0-5 age, while males were distributed over 0-4 age. The length and weight of the examined specimens range between 12.86-70.6 mm ; 0.023- 6.865 g, respectively. Length–weight equation for females was determined as W = 0.0111TL3.286(R² = 0.989) and W = 0.0113TL3.304 (R² = 0.970) for males. While M : F ratio was calculated as 1 : 1.78, it was observed that the ratio carry seasonality and age variance. In regards to Gonadosomatik index and gonad developments, it was determined that reproduction season was distributed between March–August. Average egg size was calculated as 1,80 mm, while the range of egg sizes is 1.30–2.72 mm. Correlation between fecundity and length, weigth, gonad weight and age was determined and it was concluded that the strongest correlation was between fecundity and age. Fecundity and age correlation equation is; F=171.58(t)1.067 (R² = 0.907).