The Whatcom Marine Mammal Stranding Network (WMMSN) is asking boaters and beachgoers to keep an eye out for seal pups this summer, as June through August is pupping season for harbor seals.
Harbor seals are considered true seals because they lack external ear flaps known as pinnae. Their fur varies from light tan to gray with spots, and adults can reach six feet in length. They are solitary at sea but gather on beaches, rocks, and exposed reefs to regulate their body temperature, rest, avoid predators and, in the summer months, give birth to a single pup.
At birth, a pup’s fur resembles its parents, though a pup born early may retain its woolly lanugo coat for several days before shedding it. They are able to swim within minutes of birth and often accompany their mother on dives while she hunts. Occasionally a mother will leave her pup on a beach or rock for up to 48 hours while she forages for food. The pups are nursed with thick, fat rich milk for three to four weeks, then weaned and abandoned. Having tripled in weight, the pups are now ready to hunt on their own using the skills learned while foraging with their mothers.
Gestation in harbor seals lasts about 12 months and like other seals and sea lions they are capable of delayed implantation, so the embryo does not actually implant for two to three months after fertilization. This allows the female to recuperate from the physical stress of giving birth and nursing.
Harbor seals are one of the smallest pinnipeds (the scientific classification for seals, sea lions, and walruses) living along the shores of Washington. Other seasonally found pinnipeds in the Pacific Northwest include Steller sea lions, elephant seals, California sea lions and, rarely, fur seals. Harbor seals are preyed upon by mammal eating “transient” killer whales and on rare occasions Steller sea lions. In other areas they are hunted by sharks as well.
Pinnipeds are protected under the Marine Mammal Protection Act (MMPA) and it is illegal to disturb or harass them. Violators of the MMPA can face a fine of up to $100,000 and or up to a year in prison. The Marine Mammal Stranding Network recommends keeping a distance of 100 yards. It is crucial that people and pets leave pups undisturbed. Interaction can cause stress or injury to the pup, and interfere with a mother’s return and causing her to abandon her pup. Seals can be aggressive and diseases can be passed to people and pets. Unlike sea lions, seals cannot walk on their hind flippers so land locomotion is slow and awkward consisting of caterpillar-like undulations. It is healthy and normal for pinnipeds to be on land. However, if an animal appears distressed or injured, or is on a well-populated beach, alert the WMMSN.
To report a marine mammal strandings and violations call the NOAA Hotline: 800/853-1964 To volunteer with the WMMSN email firstname.lastname@example.org.