Assessment of parrotfish community structure along a fishing pressure gradient in South Sinai marine protected areas, Gulf of Aqaba, Egypt

Herbivorous reef fishes, particularly Scaridae (parrotfishes), play many critical roles in maintaining coral reef health and resilience. As coral reefs continue to decline globally, preserving a sustainable level of parrotfish communities has become a top priority. In Egypt, the Gulf of Aqaba has been zoned into three management categories, offering varying levels of protection for coral reef fisheries, ranging from no-take to open-access fisheries. Hence, this study compared parrotfish density, biomass, and size structure across these zones to assess the effectiveness of the applied conservation measures. Our survey results indicated that Chlorurus sordidus, Scarus niger, Hipposcarus harid, and Scarus ferrugineus were the most abundant parrotfish species, accounting for 83.6% of the total density and 79.8% of the total biomass. Our study sites showed a noticeable fishing pressure gradient, where total parrotfish density (all species combined) was 1.3 and 2.3 times higher on unfished reefs than on moderately and heavily fished reefs, respectively. Similarly, the corresponding biomass values were 1.6 and 3.7 times higher on unfished reefs. Furthermore, the abundance of large-sized parrotfish individuals (>30 cm, Total Length) declined significantly from 25.9% and 17% of the total density on unfished and moderately fished reefs, respectively, to 8% on heavily fished reefs. In contrast, the abundance of small-sized individuals (10–20 cm, TL) increased with increasing fishing pressure, ranging from 18.4% on unfished reefs to 31.4% and 43.7% on moderately and heavily fished reefs, respectively. This study concluded that the present results provide important information that has management and conservation implications for artisanal fisheries in South Sinai marine protected areas (MPAs).