Fast‐Growing, Short‐Lived, and Sex‐Changing: Life History of the Blue‐Barred Parrotfish (Scarus ghobban) From the Solomon Islands

Abstract

The population dynamics of the blue-barred parrotfish (Scarus ghobban) was examined to estimate key life-history traits of this important reef fishery species in the Solomon Islands. The population was dominated by individuals within the 220–239 mm size class, corresponding to a modal age of 1-year-olds. Maximum observed size and age were 350 mm (SL) and 5 years, respectively. von Bertalanffy growth parameters were estimated as an asymptotic length (L∞) of 296.66 mm and a growth coefficient (k) of 1.06. Sex-specific growth trajectories revealed significant sexual dimorphism, with males attaining greater lengths than females at equivalent ages (p < 0.05). The relationship between length and weight was positively allometric (b = 3.67), indicating a preference for weight gain before somatic growth. Histological analyses of gonadal tissue provided evidence of sequential hermaphroditism. Dual male developmental pathways (diandry) were identified, consistent with both primary and secondary male formation. These findings highlight the rapid growth, early maturation and complex sexual ontogeny of S. ghobban, traits which likely underpin its ecological adaptability in coral reef environments.