Sardines live in large schools that may contain thousands of fish. They typically feed on plankton and are close to the bottom of the food chain; many different kinds of predators eat sardines, including humans. Sardines fall victim to predation from other fish, marine mammals and birds, often being taken in huge numbers due to the concentration of large quantities of sardines in a single area.
Cetaceans: Whales and Dolphins
Some of the largest creatures in the ocean eat sardines -- they are a favorite meal of some of the baleen whales that eat by straining their food rather than biting it. When feeding, whales, such as the humpback and the minke, open their mouths wide and scoop up huge quantities of sardines, then squeeze out the excess water before swallowing the fish. Many dolphins and porpoises, such as the black dolphin and the harbor porpoise, also consume sardines, typically by hunting them down and then grabbing individual fish.
Pinnipeds: Seals and Sea Lions
Sardines form an essential part of the diet of many pinnipeds like the Mediterranean monk seal and the Galapagos sea lion. These mammals feed in shallow waters near the coast where it can be harder for the sardines to get away and easier for the hunters to corner them. Depending on what’s available, seals and sea lions animals may also add octopus, squid, eels and other fish to their diets, typically chasing after and grabbing the prey item and then using their teeth to capture and kill their food.
Many other kinds of fish eat sardines; they are prey for almost anything that’s bigger than they are. Although sardines congregate in huge schools and use their synchronized swimming displays to confuse predators, many fish still manage to catch them and depend on sardines as a dietary staple. The biggest fish in the sea, a baleen feeder like many of the whales, the whale shark makes sardines a regular part of his diet. Some of the other fish that eat sardines include mackerel, tarpon and sharks.
Sea Birds and Penguins
Sardines often swim at or near the surface, especially if they’re trying to escape underwater predators. This is a cue for sea birds to dive in and grab a meal, and terns, gannets and brown pelicans are quick to take advantage of the situation. Penguins such as the Galapagos penguin also eat sardines, either devouring them when they catch them or saving them to take back to the nest to regurgitate and feed to their young.
- Monterey Bay Aquarium: Pacific Sardine
- Animal Diversity Web: Herrings, Shads, Sardines, Menhadens
- Wild Ocean: Species Identification Guide: Sardines
- Animal Diversity Web: Common Minke Whale
- The Mammals of Texas: Humpback Whale
- Animal Diversity Web: Black Dolphin
- Animal Diversity Web: Harbor Porpoise
- Animal Diversity Web: Mediterranean Monk Seal
- Animal Diversity Web: Galapagos Sea Lion
- Animal Diversity Web: Whale Shark