Halibut are among the largest flatfish, with two main species inhabiting the cold, deep marine environments of the Northern Hemisphere. The Pacific halibut (Hippoglossus stenolepis) is found across the North Pacific, while the Atlantic halibut (Hippoglossus hippoglossus) occupies the North Atlantic. These powerful, long-lived predators are highly valued and occupy a high level in the marine food web. Their diet changes dramatically as they grow, adapting to available prey at each life stage.
Diet of Juvenile Halibut
Larval halibut begin their feeding habits as pelagic drifters, subsisting on zooplankton in the water column. This early stage is brief, lasting until the fish undergoes metamorphosis and settles onto the seabed.
Once settled, young halibut (typically less than 12 inches) switch to a diet of small invertebrates. Their primary food sources are tiny, shrimp-like organisms, including copepods and small crustaceans such as mysids and decapods. This focus on small, bottom-dwelling life is a transitional phase before they hunt larger prey.
Primary Prey of Adult Halibut
As halibut mature and grow beyond 30 inches, their diet shifts, becoming almost exclusively carnivorous and fish-based. They are aggressive, opportunistic feeders that consume a wide variety of species near the seafloor and in the water column. Fish become the dominant food source for the largest individuals, often comprising nearly all of their stomach contents.
Primary fish prey includes groundfish such as cod, pollock, sculpins, and rockfish. They also consume smaller flatfish and sablefish, acting as top predators in the benthic community. Specific pelagic schooling fish, like sand lance and Pacific herring, are frequently targeted when available.
Beyond fish, adult halibut incorporate large benthic invertebrates and cephalopods into their diet. They regularly prey on octopus and various squid species. Large crustaceans, such as crabs, and bivalves, including clams, are also consumed. Occasionally, larger halibut will even exhibit cannibalism, preying on smaller halibut they encounter.
Feeding Behavior and Habitat Influence
Halibut are masters of ambush, using their flattened body shape and mottled coloration for camouflage on the seabed. They typically lie partially buried in soft substrates like sand or gravel, waiting for prey to pass overhead. Their large mouth and sharp, conical teeth are adapted for seizing and subduing prey quickly.
Although they are bottom dwellers, halibut are strong swimmers and will leave the seafloor to pursue prey in the water column. This enables them to target fast-moving, pelagic fish like herring and sand lance. The specific composition of their diet varies based on habitat, with fish in deeper waters often consuming more groundfish and cephalopods. The seasonal movement of schooling prey also influences feeding patterns, leading halibut to concentrate where food is most abundant.