10/12/2018
JECET; December 2018- February 2019; Sec. A; Vol.8. No.1,01-013. E-ISSN: 2278–179X
[DOI: 10.24214/jecet.A.8.1.00113.]
Comparative study of the reproduction of Synodontis punctifer (Daget, 1964) upstream and downstream of the Taabo hydroelectric dam, Côte d'Ivoire.
Oussou Koffi Hervé2 * Soro Yaya2, Diaha N’guessan Constance1, N’guessan Yao2, N’Da Konan2
Synodontis punctifer is an endemic species in Ivory Coast. Its breeding strategies have been determined in Taabo Lake for sustainable management of stocks. In January and December 2016, 848 specimens were harvested, of which 367 downstream against 481 upstream. The s*x ratio was 1: 1.1 downstream and 1: 1.4 upstream in favor of females. The upstream landed fish consisting of all stages of development were large (13.82 ± 2 cm LF) compared to those downstream (12.31 ± 1.49 cm LF) where no mature individual was captured. There is a migration of juveniles from downstream to upstream for spawning. The first maturity size of males 16.5 cm (LF) is greater than females (16.1 cm LF). The evolution of the g***do-somatic ratio (RGS) and frequency of g***d maturation stages showed that S. punctifer breeds between August and September and is believed to be due to flooding in the lake. The absolute fecundity (Fa) of S. punctifer at Taabo lake was estimated at between 2735 to 20218 oocytes, an average of 6757 ± 4094.67 oocytes for females between 13 cm and 20.5 cm (LF) in size. These oocytes have diameters ranging from 0.6 to 1.2 mm, an average of 0.97 mm ± 0.09 at the time of egg-laying. As for relative fertility (Fr), it varied from 28,000 oocytes to 35,000 oocytes, an average of 123,000 ± 58,75 oocytes per kg of body weight. S. punctifer is a less prolific fish producing large size oocytes.
Keywords: First maturity - spawning period - fecundity - S. punctifer - Taabo hydroelectric dam (Ivory Coast).
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