Flounders are flatfish known for their distinctive appearance and bottom-dwelling habit. Their adapted lifestyle significantly influences their diet and hunting behaviors. Understanding their feeding habits provides insight into their survival strategies and role in marine ecosystems.
The Adult Flounder’s Menu
Adult flounders are carnivorous and opportunistic feeders, consuming a varied diet depending on their species, geographical location, and specific habitat. Their primary food sources include a range of crustaceans, such as shrimp and crabs. For example, summer flounder commonly prey on decapod shrimp species, mysid shrimp, and long-wristed hermit crabs.
Beyond crustaceans, adult flounders also consume small fish, including sand eels, weakfish, and Atlantic silversides. Marine worms and small mollusks are other common components of their diet. The specific types of prey can shift seasonally; for instance, in winter months when other food sources are scarce, shrimp may comprise a larger portion of a summer flounder’s diet. Flounders found in estuaries, sandy bottoms, or near structures like docks and coral reefs will adapt their diet to the available prey in those environments.
From Larva to Adult: Dietary Shifts
A flounder’s diet undergoes significant transformations as it progresses through its life stages, from a free-swimming larva to a bottom-dwelling adult. Newly hatched flounder larvae are pelagic, meaning they drift with ocean currents and feed on microscopic plankton and zooplankton. This initial diet supports their early development before they begin their remarkable metamorphosis.
As flounders transition into the juvenile stage, their diet shifts to smaller invertebrates found on the seabed. This includes tiny worms, small crustaceans like amphipods and copepods, and chironomid larvae. The development of their feeding apparatus and changes in body shape drive these dietary shifts, preparing them for the more varied prey of adulthood.
Hunting Strategies: How Flounders Catch Their Food
Flounders employ unique methods to acquire their food, primarily relying on their exceptional camouflage and ambush predation. Their ability to change color and pattern allows them to blend seamlessly with the seafloor, whether it is sand, mud, or gravel, making them nearly impossible for prey and predators to spot. This cryptic coloration is achieved through specialized cells called chromatophores, which enable them to match the surrounding substrate.
Flounders are classic ambush predators; they lie motionless, often partially buried in the sediment, waiting for unsuspecting prey to swim or crawl within striking distance. When prey approaches, they can lunge forward with surprising speed to capture their meal. Their flat body shape and the migration of both eyes to one side of their head are adaptations, allowing them to effectively scan for prey while remaining hidden and pressed against the bottom. Some species may also use their swimming ability to actively chase faster-moving prey, demonstrating a dual hunting approach.