Age and Growth of Phycis Phycis (Linne, 1766) in the Gulf of Tunis

The age of fish in a population is fundamental to most of the questions fishery biologists attempt to answer about that population. The aim of this study was to report the parameters of the weight-length relationship and to estimate the age and growth of Phycis phycis (Linnaeus, 1766) in Gulf of Tunis. A sample of 272 specimens of P. phycis was collected from the landings of the small-scale artisanal fisheries between September 2007 and June 2010. The total length (TL) ranged from 14 to 55.5cm and total weight (TW) from 45 to 1779g. Length-weight relationship were described by 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-0.158 (t+1.709))), males (TL = 67.51 (1 - e-0.168 (t+1. 993))) and combined sexes (TL = 65.73 (1 - e-0. 135 (t+2. 025))) were estimated. The females, reaching L∞ = 73.43 cm, grew faster than the males, which did not exceed 68 cm. Moreover, the females have the higher predicted asymptotic weight (W∞= 4446.08g) compared to the males (W∞= 3603.20g).Consequently, the index of performance from growth (Ф) (cm/an) of the females (Ф=2.929) was higher than the one of the males (Ф=2.883). Age estimation in gadiform fish has been known to present some difficulties due to otolith thickness, which in most species requires special processing methods so that growth increments become visible.

Full Text

FilePagesSizeAccess
20592.pdf
1691 Ko
How to cite
Romdhani Ahlem, Chater Ines, Ktari Mohamed Hédi, Dufour Jean-Louis, Mahe Kelig (2012). Age and Growth of Phycis Phycis (Linne, 1766) in the Gulf of Tunis. 14th European Congress of Ichthyology, 3-8 July 2012, Liège (Belgium). https://archimer.ifremer.fr/doc/00117/22790/

Copy this text