Density and biomass of fish populations in kirmir stream of Sakarya river, Turkey

Abstract

Bu calismada, Ic Anadolu Bolgesi’ndeki Sakarya Nehri’nin Kirmir Cayi’nda balik turlerinin yogunluk ve biyomas degerlerini tahmin etmek icin uc avli ayrilmaya dayali metot kullanilmistir. 1.5256 ha’lik alanda ornekleme yapilmis ve1. IntroductionA fish population is shaped by the geologic, chemical, physical, and biological factors within and surrounding the environment in which it lives. The relative quality of that environment affects the organisms living there, exerting positive or negative pressure on the population (Platts & McHenry 1988). The fluctuation of the fish population is really important for stock assessment and management. In this way, a major decline and rise in the population size or the population biomass can be detected, and appropriate management strategies can be adopted (Chen et al 2004). A relatively simple and inexpensive method of evaluating the health of lentic systems is to monitor the density and biomass of the fish population (Platts & McHenry 1988; Bohlin et al 1989).Density and biomass estimates of targeted species by electrofishing capture data are most often generated using depletion (or sometimes referred to as removal) (Moran 1951; Zippin 1958; White et al 1982) or the mark-recapture method (Ricker 1975; Zubik & Fraley 1988). Because these methods are labour intensive, they have been recommended only when researchers require detailed knowledge of the target population. Typically, removal methods have been used in stream environments where fish capture is by electrofishing during two to four intensive sampling periods over a short time period (often within a day) (Kelso 1989)