As the tide receded, the harbor seal’s sleek form nearly blended into the dappled gray mudflats. She was restless, shifting her hindquarters, turning to inspect them. With just one more twitch, she gave a push and a small head emerged from between her hind flippers. The pup’s advent was heralded by the clamor of gulls squabbling over the afterbirth. Calling softly, sniffing and nuzzling her pup, the mother established a pair bond that would last just a few weeks, but which would equip her pup for survival on land and at sea. Welcome to springtime on the coast, to Greater Farallones National Marine Sanctuary.
The Pacific harbor seal, Phoca vitulina richardii, ranges from Alaska to Mexico; nearly 31,000 live and thrive in California. The sanctuary is home to around one-fifth of them, protecting them and their habitats along the coast: sandy beaches, estuaries, and offshore rocks, from Point Arena to Point Año Nuevo. Large concentrations are found at Point Reyes, Tomales Bay and Bolinas Lagoon, and at the Russian River mouth.
From afar they appear almost feline: rounded head, flat muzzle, long whiskers, large eyes. They’re small – only about 250 pounds, and six feet long. Like all true seals they lack external ear flaps, and cannot rotate their hind flippers around to walk on land; instead, using their fore flippers, they hitch across the sand. Under water, they move smoothly, with a full-body scull. Their pelts can range from nearly all white with a few dark spots, to almost black with white markings. Harbor seals haul out in groups ranging from a few to several hundred. Though they do not migrate long distances, they travel offshore and even upriver and into inlets in search of prey such as fish and squid.
Natural threats include white sharks and killer whales. Though harbor seals are federally protected by the Marine Mammal Protection Act of 1972, they suffer from fishing gear entanglement, illegal feeding and harassment, habitat loss, boat strikes, oil spills, and chemical contaminants. Human disturbance impacts them, too. Curious seals may approach divers in the water, but on shore they become wary, and may stampede, or “flush,” into the water. They must haul out to normalize their body temperature and blood gases after foraging dives. To avoid disturbing them, keep at least 300 feet away. If they notice you, or show agitation, slowly back away.
Pupping season is March through June. Females generally give birth between tides, always to a single pup. Pups can swim at birth, and may “piggyback” on their mothers during foraging trips. They nurse for three or four weeks, and sometimes a mother may leave her pup unattended while feeding at sea, but will return to care for it. This is a time for special caution: maintaining the mother-pup bond means life or death for the pup. In the Bay Area, for many years pup survival declined alarmingly at Tomales Bay and Bolinas Lagoon, due to hikers, birders, clam diggers, dogs, aircraft, and boaters. But a sanctuary outreach and monitoring program reversed this trend. Similarly, the Point Reyes National Seashore, Sea Ranch Stewardship Task Force, and the Stewards of the Coast and Redwoods introduce visitors to the seals, and to wildlife watching awareness and “etiquette.”
If you think a seal needs rescue, do not touch it, but call The Marine Mammal Center Rescue Line at once: (415) 289-7350. If anyone attempts to harm or move a seal, call the NOAA Fisheries Enforcement Hotline (1-800-853-1964) to report it.
This spring, watch for these shy animals that grace our shores. Keep those binoculars handy, and you’ll enjoy their natural behaviors—even if it’s just seal-napping on the beach.
To discover how NOAA conducts harbor seal monitoring, see https://vimeo.com/54552360 To learn about visiting the sanctuary: https://farallones.noaa.gov/visit/locations.html
NOTE: Here's a link to a harbor seal birth, by a state government agency (Washington Dept. of Fish & Wildlife) and posted on YouTube, length 4:24 minutes. It's wonderful to see the birth, and their first swim.
