Age and Growth estimation of forkbeard Phycis phycis (Linnaeus, 1766) [Actinopterygii, Gadiform, Phycidae] from the Gulf of Tunis

Abstract

The age and growth of Phycis phycis (Linnaeus, 1766) were studied from a sample of 272 specimens collected in the Gulf of Tunis landings of the small-scale artisanal fisheries between September 2007 and June 2010.Length- weight relationships were allometrically positive for the females (TW = 0.0083*TL3. 0703), males (TW= 0.0063*TL3.1471), and both sexes (TW= 0.0082*TL3. 0759).No significant differences were found between males and females (ANCOVA, p = 0.426). Symmetry between the right and left otolith was compared. The relation between the total length (TL) of fish and the weight of the otolith (Wo) did not show a significant difference between the right (Wo = 0.12 TL – 0.163) and left otolith (Wo = 0.11 TL – 0.124) (ANCOVA, p>0.05). The relationships between otolith radius and otolith weight with age, showed that there are no significant differences between males and females (ANCOVA, p>0.05). The growth parameters for females (TL = 73.43 (1 - e[1]0.158 (t+1.709))), males (TL = 67.51 (1 - e[1]0.168 (t+1. 993))) and all sample (TL = 65.73 (1 - e[1]0. 135 (t+2. 025))) were estimated. The females, with L∞ = 73.43 cm, grew faster than the males, which L∞ did not exceed 68 cm. Consequently, the index of growth performance (Ф: cm/an) of the females (Ф=2.929) was higher than that of the males (Ф=2.883).