Population parameters and reproductive biology of the streaked gurnard, Chelidonichthys lastoviza (Bonnaterre, 1788) in the Egyptian Mediterranean waters (GFCM-GSA 26)

The population dynamics and reproduction of the streaked gurnard, Chelidonichthys lastoviza (Bonnaterre 1788), has been studied based on collected data between January 2020 and December 2021 from the Egyptian Mediterranean waters. In this study, age, growth, mortality, critical lengths, sex, gonadal maturation and spawning season were determined. A total of 1215 specimens ranged between 7.9 and 26.6cm TL and 5 to 220g total weight were sampled. Total lengths of males ranged from 11.5 to 24.4cm (n= 474), and of females from 11.0 to 26.6cm (n=553). The maximum observed age based on otolith readings was 4 and 5 years for males and females respectively. The length-weight relationship was estimated as W= 0.0093L^3.0487 for males and W= 0.0089L^3.0673 for females indicating an isometric growth. The von Bertalanffy growth equation was Lt= 27.56(1-e^-0.433(t+0.62)) for males and Lt= 30.92(1-e^-0.299(t+0.92)) for females. The growth performance index was computed as 2.52 (males) and 2.46 (females). Males mature at smaller lengths and younger ages (Lm= 15.2cm, Tm= 0.61 years) than females (Lm=15.8cm, Tm= 0.71 years). The male: female ratio was 1:1.17. The gonado-somatic index (GSI) values defined a protracted spawning season starting in November till February with a peak in January and December for males and females respectively.