BIOLOGICAL PARAMETERS OF THE SADDLEAD BREAM OBLADA-MELANURA IN THE EASTERN ADRIATIC

Age, growth, sex ratio, and mortality were analysed for saddlead bream collected in the eastern Adriatic from June to August in 1993 and 199 4. The slopes (b values) of the total length-weight regressions, which differ significantly between sexes, indicate positive allometric grow th for females (b=3.123) and isometric growth for males (b=3.017) (N=5 341). Fish aged 1-11 years were present in the samples (N=1729). Growt h in length for both sexes was expressed using the Bertalanffy equatio n, L-t = 34.13(1 - exp (-0.208(t + 0.750))). Females grew slower (K=0. 201) than males (K=0.233). The overall ratio was 1:1.20 in favour of f emales (P<0.05). Males were dominant in length classes 11.0-20.0 cm, f emales in length classes 21.0-33.0 cm. All individuals larger than 29. 3 cm were female. Total and natural mortality were Z=1.08 years(-1) an d M=0.47 years(-1). The exploitation rate, E=0.56, revealed a high fis hing pressure on the stock in the studied area. (C) 1998 Elsevier Scie nce B.V. All rights reserved.