Harbor seal

Harbor seals eat mostly fish.

They also eat squid, octopus and crabs. They dive under the water to catch them.

Harbor seals eat mainly fish, plus shellfish, crustaceans, octopus and squid. They are opportunists, which means they eat whatever is plentiful at the time. In Alaska their food includes herring, cod, salmon, flounder and sand lance.

They hunt in the sea, in estuaries and sometimes in rivers and lakes. Most dives are short and shallow, less than 20 meters deep and under 4 minutes, but a harbor seal can dive as deep as 500 meters and stay underwater for over 20 minutes.

Harbor seals are opportunistic predators of fish, shellfish and crustaceans that likely exploit seasonally abundant prey. In Alaska common prey includes walleye pollock, Pacific cod, capelin, eulachon, Pacific herring, sand lance, Pacific salmon, sculpins, flatfish, octopus and squid.

They make both shallow and deep foraging dives depending on prey. Most dives are under 20 meters and 4 minutes, but they can reach 500 meters and last over 20 minutes, aided by high blood volume, reduced peripheral circulation, a slowed heart rate and high muscle myoglobin. Seals can even sleep underwater, surfacing about every 30 minutes.

Harbor seals rest together on rocks and beaches.

In the water they are curious. They pop up behind boats to look around! If they feel scared on land, they slide back into the sea.

In the water harbor seals usually swim alone, but they rest together in groups of a few to thousands. Resting together helps them stay safe, because each seal needs to spend less time watching for predators.

Harbor seals are curious but shy. They often pop up close behind boats to look around. On land they move slowly, so if they feel threatened, they quickly slip back into the water. Their most common predator is the killer whale. Sharks, sea lions, wolves, bears and coyotes catch them too, and bald eagles may take newborn pups.

Harbor seals are usually solitary at sea but haul out in groups of a few to thousands, to rest, regulate body temperature, molt, socialize, give birth and nurse. Seals that haul out in groups spend less time vigilant for predators than those resting alone.

In the water they are inquisitive but elusive, often surfacing close behind boats; ashore, because they move awkwardly, they enter the water quickly when disturbed, and NOAA Fisheries warns that repeated disturbance can degrade important haul-out areas. Killer whales are their most common predator; sharks, sea lions, wolves, bears and coyotes also prey on them, and bald eagles may take newborn pups.

There are lots of harbor seals, and laws protect them.

If you see a seal resting on a beach, stay far away and let it rest. Never feed a seal.

Harbor seals are not endangered. Scientists list them as Least Concern. Long ago, bounty hunters were paid to kill harbor seals in parts of the United States, but that ended in 1960, and since a law protecting marine mammals was passed in 1972 many populations have grown.

Harbor seals can still get tangled in fishing gear and litter, be hit by boats, and be disturbed by people and boats at their resting places. Pollution can build up in their bodies. Watch seals from at least 50 yards away, and never feed them.

The IUCN's 2016 global assessment lists Phoca vitulina as Least Concern, with about 315,000 mature individuals and an unknown overall trend. In the United States, state-financed bounty hunting ended in 1960, and since the Marine Mammal Protection Act of 1972 many populations have grown, though trends differ: some Alaska stocks likely declined between 2011 and 2018, while others were stable or increasing.

Threats include entanglement in gillnets, trawls and debris, vessel strikes and disturbance, illegal feeding, habitat loss from coastal development, shrinking glacial ice in Alaska's fjords, and contaminants and microplastics that accumulate in blubber and pass to pups. NOAA Fisheries works with Alaska Native organizations on subsistence management and asks viewers to keep 50 yards away.