Stock Assessment of Two Parrotfish, Hipposcarus harid and Scarus ferrugineus in Jeddah, Saudi Arabia
Stock Assessment of Two Parrotfish, Hipposcarus harid and Scarus ferrugineus in Jeddah, Saudi Arabia
Ahmad Osman Mal1 and Mohamed Hosny Gabr1,2,*
ABSTRACT
The current stock status of two Parrotfish, Hipposcarus harid and Scarus ferrugineus in Jeddah was assessed. Scales were used for age determination and back calculations of length-at-ages. The growth parameters were estimated to be: the asymptotic length L∞ = 54.044 cm, the growth coefficient K = 0.168 year-1, and age at zero length to = -0.707 year for H. harid and L∞ = 51.238 cm, K = 0.170 year-1, and to = -0.889 year for S. ferrugineus. The total ‘Z’, natural ‘M’, fishing ‘F’ mortality coefficients and current exploitation ‘Ecur’ were 0.96, 0.294, 0.670 year-1, and 0.69 year-1, respectively for H. harid and 0.77, 0.299, 0.471 year-1, and 0.61 year-1 respectively for S. ferrugineus. The maximum yield per recruit at the current fishing mortality was 108.1 g for H. harid and 137.6 g for S. ferrugineus. The biological reference points: Fmax = 0.401 year-1 and F0.1 = 0.245 year-1 for H. harid and Fmax = 0.434 year-1 and F0.1 = 0.307 year-1 for S. ferrugineus were lower than the current fishing mortality, reflecting an over-exploitation for both species. The current fishing mortality is recommended to be decreased to the target reference point F0.1 = 0.453 year-1 for H. harid and F0.1 = 0.466 year-1 for S. ferrugineus after increasing the age at first capture to be 3 years for both species.
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October 2020
Vol. 52, Iss. 5, Pages 1631-2026
