Bafra Balık Gölü Ve Eğirdir Gölü'nde Yaşayan Balık Popülasyonlarında Opak Birikim Analizi Ve Yaş Doğrulaması

Abstract

The Crucian carp, Carassius auratus gibelio (Bloch, 1758) which haseconomical importance and distributing fastly in our country has been monthlysampled from two lakes. It is aimed to evaluate the effects of ecological factorson annulus formation by comparison of bony structures and provideinformation about annulus formation period from two ecologically differentlakes, Bafra Fish Lake DQG(÷LUGLU/DNHThe study has been carried out in three steps. Firstly, the most reliablebony structure has been determined for individuals from each lake and therelationships between bony structure and fish growth has been found out.Secondly, the deposition of opaque increment on bony structure and its timinghas been determined by opaque increment analysis. Thirdly, the relationbetween reproduction, feeding and growth rings has been evaluated.It has been observed that growth rings were not of same character inindividuals living in different ecological conditions. Though the same bonystructure was used from two different lakes, age reading has revealed thatespecially sagitta have different characters. Sagitta removed from Bafra FishLake samples had smooth distal surfaces but did not include any circulus orannulus. Proximal surfaces were observed to have an irregular shape. On theFRQWUDU\ VDPSOHVIURP(÷LUGLU/DNHZHUH DVXVXDODQGQRWSUREOHPDWLF7KHirregular deposition in Bafra Fish Lake samples make it impossible to usesagitta in age determination and these specimens were excluded from agereading process.Three readings were done in five bony structures obtained from BafraFish LDNHVDQGLQVL[IURP(÷LUGLU/DNH7KHPHDQDJHSHUFHQWDJUHHPHQWDQGcoefficient of variation for each bony structure were determined. In conclusion,vertebra was found to be the reliable bony structure for Bafra Fish LakeSRSXODWLRQ DQG VDJLWWD IRU (÷LUdir Lake. Annulus formation was validated byopaque increment analysis for two populations. The monthly percentage ofhyaline zones, the length of marginal increment and the monthly variation ofmarginal increment rate were determined to show the period of annulusformation.In conclusion, it has been found that the reliable bony structure for agedetermination varies in different populations of this species and the ringdeposition has proved to be annual. Marginal increment analysis showed thatannulus formation occured during October-April.Key Words: Crucian carp, (Carassius auratus gibelio), age validation, annualLQFUHPHQWVDJLWWDYHUWHEUD%DIUD)LVK/DNH(÷LUGLU/DNH