Growth Parameters, Mortality and Optimal Exploitation of the Rock Fissures of Panulirus Homarus megasculptus in the Water's Coast of Hadhramout Yemen

Abstract

This study aimed to evaluate selected biological parameters and population dynamics of the 
scalloped spiny lobster, Panulirus homarus megasculptus (P. h. megasculptus), along the Hadhramout 
coast during the period from October 2023 to February 2024, in order to contribute to filling the gap in 
biological information required for the sustainable management of its fishery. 1,040 specimens were 
analyzed to estimate sex ratio, growth parameters, mortality and exploitation rates, length at first capture 
(Lc), length at first sexual maturity (Lm), and relative yield per recruit (Y/R). The results indicated a 
balanced sex ratio between males and females. Moreover, the majority of the captured individuals were 
below the legal minimum size for harvesting. Growth parameters estimated using the ELEFAN method 
revealed a moderate growth pattern for the studied population, with a growth coefficient of K = 0.49 
year⁻ ¹. Natural mortality (M = 1.28 year⁻ ¹) was higher than fishing mortality (F = 0.28 year⁻ ¹), 
resulting in a low exploitation rate (E = 0.18), which suggests that the stock is currently underexploited. 
The length at first capture was estimated at Lc = 76 mm, while the length at first sexual maturity was Lm 
= 66.9 mm. The relative yield per recruit was estimated at Y/R = 0.57. These findings indicate the 
potential for increasing the exploitation of P. h. megasculptus within the framework of sound fisheries 
management, provided that the legal minimum size limit is strictly enforced, thereby ensuring resource 
sustainability and the conservation of the natural stock along the Hadhramout coast.