Pollock are marine fish that belong to the cod family, Gadidae. These species are widely distributed, primarily found in the cold waters of the North Pacific and North Atlantic Oceans.
Primary Food Sources of Pollock
Pollock are carnivorous fish, and their diet primarily consists of smaller organisms found in their marine environment. They consume a variety of zooplankton. Among these, copepods and euphausiids, commonly known as krill, form a substantial part of their diet. Krill are small crustaceans that are highly abundant in the cold waters where pollock reside.
As pollock grow, their diet diversifies to include larger prey. Smaller fish species become an increasingly important food source for adult pollock. This can include juvenile herring, sand lance, capelin, and Asian smelt. They are opportunistic feeders. In some instances, pollock have also been observed to consume squid.
Dietary Changes Across Pollock Life Stages
The diet of pollock changes significantly as they progress through different life stages, adapting to their increasing size and foraging capabilities. Newly hatched pollock larvae are microscopic and primarily feed on phytoplankton, which are tiny marine plants, and very small zooplankton. This initial diet provides the necessary energy for their rapid early growth.
As pollock mature into juveniles, their diet shifts towards larger zooplankton, such as copepods and small crustaceans. At this stage, they begin to develop the ability to pursue more active prey, though they are still limited by their size. The transition from a planktonic diet to one that includes more substantial prey is a gradual process.
Adult pollock exhibit the broadest and most varied diet, preying on a wide range of larger zooplankton and small fish. They are capable of consuming a diverse array of organisms found in both the water column and near the seafloor. Instances of cannibalism, where adult pollock consume the larvae and fry of their own kind, have also been documented.
Pollock Feeding Behavior
Pollock exhibit specific behaviors to acquire their food, which are influenced by their schooling nature and their role as active predators. They are known to be schooling fish, and this behavior can enhance their foraging efficiency. By moving in large groups, pollock can more effectively locate and encircle prey, making it easier to capture food items.
Their feeding strategies include both filter-feeding on dense concentrations of zooplankton and actively pursuing smaller fish. When feeding on zooplankton, they may swim through patches of these organisms, filtering them from the water. When targeting fish, pollock will actively chase and ambush their prey. This opportunistic and adaptable feeding approach allows them to thrive in various marine environments.