Autecology of chub, Leudscus cephalus (L.), in a Greek stream, and the use of the pharyngeal bone in fish predator-prey studies

Abstract

. The autccology of chub, Leudscus cephalus (L.), in the Renlina Stream, Greece, was carried out in an effort to obtain information on the age, growth, mortality and reproduction of this species. Fork length increment during the first year of life was 8·9cm, after which it decreased. Life span was short (maximum age 8 years) and the instantaneous mortality rates were higher for the older age-groups. Chub reached sexual maturity at the second year of life for both sexes and spawning occurred from the second fortnight of April into May, at a mean water temperature of 18°C. The relationship between fecundity (F) and fork length (1) was F= 0·0797 L3·63 The average density and biomass were 1·06 fish.m−2 and 11·38g.m−2 respectively. The relationship between L and the pharyngeal bone size [gape (G), tip (T) and shank (S)] in mm and caudal fin length (C) (cm) can be described by the equations: L= 0·8605 + 1·550 G, L= -0·0703 + 1·332 S, L= 1·092 + 1·615 T and L= 1·032 + 2·934 C.