Bigeye Trevally (Caranx sexfasciatus), commonly known as the bigeye jack, is a pelagic fish belonging to the Carangidae family. This species inhabits the warm waters of the Pacific and Indian Oceans. In this study, we provide an in-depth analysis of the morphology, distribution, reproductive behavior, feeding preferences, and ecological significance of the Bigeye Trevally.
Bigeye Trevally exhibits an elongated, streamlined body with an average length ranging from 30 to 40 centimeters (12 to 16 inches). However, larger individuals can reach a maximum recorded length of 75 centimeters (30 inches). The species displays a bluish-green coloration on its upper body, contrasting with a silvery hue on the lower part. Notably, Bigeye Trevally possesses a relatively larger eye compared to other Carangidae members. This prominent feature aids in visual acuity and prey detection. The average lifespan of Bigeye Trevally is estimated to be around 12 to 15 years.
The activity of Bigeye Trevally peaks during the early morning and late afternoon, coinciding with favorable water temperatures for feeding. This species thrives in tropical and subtropical regions where water temperatures range from 77°F to 86°F (25°C to 30°C). Seasonal variations affect their behavior, with spring months exhibiting higher abundance near coastal areas and coral reefs due to increased food availability. In summer, Bigeye Trevally migrates to offshore waters, tracking schools of baitfish and other prey. Autumn sees them capitalizing on the movements of prey species in estuaries and lagoons. Reduced metabolic rates and feeding activity characterize their winter behavior due to lower water temperatures.
Bigeye Trevally displays a broad geographical distribution across the Pacific and Indian Oceans. This species can be found in tropical and subtropical waters along the Red Sea, East African coast, Arabian Sea, Indian Ocean islands, and various regions of the Pacific Ocean, including Hawaii, Japan, Australia, and New Zealand. Coastal areas with coral reefs, rocky outcrops, and underwater structures are preferred habitats for Bigeye Trevally. Their schooling behavior makes them attractive targets for both recreational and commercial fishing endeavors.
The reproductive cycle of Bigeye Trevally follows an annual pattern, with spawning occurring during warmer months when water temperatures range from 77°F to 86°F (25°C to 30°C). These optimal conditions ensure successful fertilization and egg development. Spawning takes place in large aggregations within open water, where females release their eggs simultaneously with the males releasing sperm. This synchronized spawning behavior enhances the chances of successful fertilization. Eggs hatch within a few days, and the resulting larvae undergo a pelagic phase before eventually settling near coastal habitats.
Bigeye Trevally is a carnivorous species with a diverse diet comprising smaller fish and various invertebrates. They feed on a wide range of prey items, including small crustaceans, squid, shrimp, and other small fish species. Utilizing their streamlined bodies and large eyes, Bigeye Trevally employs hunting strategies such as ambushing and schooling foraging to efficiently locate and capture prey.
Bigeye Trevally plays a crucial ecological role in marine ecosystems as a predatory species. By regulating the populations of small fish and other
aquatic organisms, this species contributes to the overall balance and health of the ecosystem. Maintaining the abundance of prey species helps sustain biological diversity and ensures the stability of aquatic communities. Furthermore, Bigeye Trevally holds significance for both recreational anglers and commercial fishermen. Its popularity among sport fishermen contributes to the tourism industry in coastal regions, while commercial fishing supports local economies and food supplies.