The main prey species reported for Fiordland penguins are cephalopods (85%, mainly Arrow squid, Nototodarus sloanii), followed by crustaceans (13%, primarily Krill, Nyctiphanes australis) and fish (2%, mainly Red Cod and Hoki).
As of July 2012, Sagar Sampada has completed 303 oceanographic expeditions, which includes one expedition to the Southern Ocean in the winter of 1995-96 for surveying fishery resources in Antarctic waters (Krill Expedition, FIKEX 1995).
Squid and euphausiids (krill) make up the bulk of their diet; small fish are also taken.
Larger leopard seals probably switch from krill to more substantial prey, including king, adelie, rockhopper, gentoo, emperor penguins and chinstraps, and less frequently, other seals, such as crabeater seal.
Krill and other crustaceans are the most important component of the diet but the species also feeds on small fish such as the Antarctic silverfish and squid such as Psychroteuthis, Gonatus and Galiteuthis.
Thysanoessa raschii, sometimes known as Arctic krill, is one of the most common euphausiid species of the subarctic and Arctic seas.
They are omnivorous, but prefer a meat-intensive diet of krill, bloodworms, Daphnia, earthworms and live insects.