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Annual reproductive cycle, spawning periodicity and sexual maturity of false scad Caranx rhonchus (Geoffroy Saint‐Hilaire, 1817) (Pisces, Carangidae) from the South‐Eastern Mediterranean (Gulf of Gabès, Tunisia)
Author(s) -
Sley A.,
Hadj Taeib A.,
Jarboui O.,
Ghorbel M.,
Bouain A.
Publication year - 2015
Publication title -
journal of applied ichthyology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.392
H-Index - 62
eISSN - 1439-0426
pISSN - 0175-8659
DOI - 10.1111/jai.12675
Subject(s) - carangidae , biology , sexual maturity , fish measurement , reproductive biology , population , mediterranean climate , sex ratio , maturity (psychological) , zoology , fishery , ecology , demography , fish <actinopterygii> , embryo , developmental psychology , psychology , sociology , embryogenesis
Summary The reproductive biology of Caranx rhonchus (Geoffroy Saint‐Hilaire, 1817) (Pisces, Carangidae) was studied in the Gulf of Gabès (Mediterranean Sea) from June 2004 to May 2006. Of 1313 individuals examined, 668 were females (50.9%) and 645 were males (49.1%). The overall sex ratio did not deviate significantly in favour of females (♀ : ♂ = 1.04 : 1). Monthly changes in the Gonado–Somatic Index ( GSI ) showed a rapid increase from May to June and an extended very high level from June to September (4.43–3.47% for females and 3.35–2.61% for males), before declining sharply in October (down to 2.02% for females and 0.57% for males). The gametogenesis activity began with a pre‐maturation phase from March to May, followed by a ripe‐spawning phase from June to September. From the last days of July to the end of October, the gonads were in the spent and post‐spawning stages. From November to early May, gonads were in the resting stages. The size at which 50% of the population reached sexual maturity was not significantly different between males and females : males attained sexual maturity at fork length FL 50 = 161.20 ± 0.37 mm (n = 262), whereas females attained maturity at FL 50 = 160.70 ± 0.23 mm (n = 296). The age of maturity for both sexes occurred at 2.1 years.