The Barramundi, Lates calcarifer, is a highly sought-after species across the Indo-Pacific region, spanning from Australia to Southeast Asia and India. Known for its distinct flavor and powerful fighting ability, it is a prized target for both commercial and sport fishing. The species possesses a unique life cycle trait, being catadromous, which means it is born in saltwater and spends its adult life primarily in freshwater rivers and estuaries before returning to the sea to spawn. This movement between environments dictates the varying diet the Barramundi consumes throughout its life.
Early Life Prey
The Barramundi diet begins with minute organisms, dictated by the size of the newly hatched larvae. As the fish grow, their feeding habits progress rapidly to meet high energy demands. Initially, larvae feed on rotifers and copepod nauplii, which are microscopic zooplankton abundant in the brackish nursery habitats near the coast.
As the young fish grow past a few centimeters, their diet quickly expands to include larger zooplankton, such as copepodites, adult copepods, and cladocerans. Juvenile Barramundi, once they reach the freshwater upper reaches of rivers, begin to incorporate benthic organisms, such as chironomid larvae and small aquatic insects, into their feeding repertoire.
The Adult Diet
The mature Barramundi is an opportunistic predator, consuming prey that changes depending on its current environment. Studies of stomach contents show a clear dietary shift with size; juveniles under 300 millimeters primarily consume macrocrustaceans like prawns and crabs. Once the fish exceeds 400 millimeters, its diet becomes overwhelmingly piscivorous, with fish making up to 87% of its food intake.
In estuarine and coastal waters, the diet consists mainly of schooling baitfish like mullets, herring, and smaller species such as bony bream. When Barramundi move into freshwater environments, they consume species like catfish, as well as terrestrial animals that fall into the water. The adult Barramundi also consumes amphibians, insects, spiders, and occasionally small aquatic reptiles, including baby crocodiles.
Hunting Style and Strategy
The Barramundi is an ambush predator, relying on stealth and location rather than a sustained chase. They prefer to situate themselves near underwater structures that offer concealment and a break in the current, such as submerged logs, mangrove root systems, and rocky drop-offs. These structures allow the fish to wait for prey to pass by before launching a surprise attack.
The fish’s sensory perception is attuned to its environment, particularly the murky water it often inhabits. Barramundi use their lateral line system to detect subtle vibrations and pressure changes produced by passing prey. This capability allows them to hunt effectively in low-light conditions, peaking their feeding activity during dawn, dusk, and throughout the night. The strike is explosive, characterized by a loud gulp or “boof” as the Barramundi rapidly expands its mouth to create a vacuum, sucking the prey whole.
Diet in Aquaculture
The feeding regimen for Barramundi in commercial aquaculture is controlled and differs significantly from the wild diet. Farmed Barramundi are fed specialized, high-protein pellets formulated to maximize growth efficiency and minimize the time to market. These pellets typically contain around 48% protein, a necessary level for a carnivorous species.
The pellets blend marine and terrestrial ingredients, historically relying on fish meal and fish oil. Due to sustainability concerns regarding wild forage fish stocks, marine ingredients are increasingly replaced with plant-based alternatives. Soybean meal is a primary plant-based protein source, used alongside wheat and other cereals, though high levels can reduce palatability. Vitamins and minerals are also added to ensure a complete diet.