The Growth Parameters of the Mako Shark in the Moroccan Central Atlantic Coast
The Growth Parameters of the Mako Shark Isurus Oxyrinchus (Rafinesque, 1810) in the Moroccan Central Atlantic Coast
Jihade Alahyene, Brahim Chiahou, Hammou El Habouz, Badreddine Mekyassi, Abdelbasset Ben-bani
ABSTRACT:
The present study was carried out through regular biological sampling operations of the mako shark during a period of 24 months (October 2017 – August 2019). Specimens were collected from the commercial catches of artisanal boats operating in the Moroccan Central Atlantic Coast and landing at Sidi Ifni Port. A total of 1088 individuals were examined, including 567 females and 521 males. The total length (TL) of both sexes combined ranged from 60 to 317cm, with an average of 150.83 ± 41.51cm (mean±sd). Dominant sizes varied between 105 and 195 cm (TL). The linear regression equations showed a good positive correlation between the different body lengths (0. 983 <R <0.997). The allometric equations between the two variables of weight W(t) and length L(t), where W(t) = 7 E-05 * L2.6092 , showed significantly lower allometry for the two sexes combined. The parameters of the Von Bertalanffy linear growth equation for both sexes combined were estimated as L∞ = 313.24 cm, K=0.15 year-1 and t0 = -0.68. For the same age, the sizes of males were recorded larger than those of females. Moreover, results showed that the determined longevity (tmax) was 24.75 years for males and 26.65 years for females.
Egyptian Journal of Aquatic Biology & Fisheries, Article 9, Volume 25, Issue 3, DOI: 10.21608/ejabf.2021.172860