Marine Mammal Safety Act has helped shark, seal, otter populations surge
Elephant seals flock to the Año Nuevo State Park and Point Reyes National Seashore wildlife sanctuary. The great white sharks will follow them. Sea otters go on a vigil to avoid turning into shark mints.
This wildlife phenomenon with elephant seals, great white sharks and sea otters shows right now how everything is related in nature. That story began almost 50 years ago with the Marine Mammal Protection Act. Much of the results can be seen on the coast of the Bay Area and Monterey Bay this weekend and well into winter.
Elephant seals
There were no elephant seals in Año Nuevo in 1955, and the first pup born here was suspected to be in the 1960s, according to park staff. The small numbers were a holdover from the days of commercial slaughter when elephant seals were hunted to extinction for processing into oil.
This week there are about 300 elephant seals on the mainland peninsula just off the coast of a small island. With annual migration in full swing, those numbers are likely to hit 500 by early November and 3,500 by January. Starting in mid-winter, puppies averaging 75 pounds will be born, raised, and taught to swim and feed.
Elephant seals: During the breeding season, there is a 3-mile guided hike surrounded by elephant seals. $ 7 per person, December 15 through March 31, reservations at www.reservecalifornia.com. Contact: Año Nuevo State Park Nature Reserve, Pescadero, 650-879-0227 or 650-879-2025, www.parks.ca.gov.
Great White Sharks: Great whites occasionally spotted on whale watching tours to southeast Farallon Island; $ 135 per person, free parking at Marina Green, San Francisco. Contact: Oceanic Society, 415-256-9604, www.oceanicsociety.org.
Sea otters: Sea otters can be spotted along the slough that leads to the mouth of Moss Landing Harbor and east of Highway 1 in the mouth; GPS location: 2370 Highway 1, Moss Landing. Contacts: Kayak Connection, Kayak Rentals, 831-724-5692, www.kayakconnection.com; Elkhorn Slough Safari, pontoon boat tours, 831-633-5555, www.elkhornslough.com; Blue Water Ventures, guided kayak tours, 831-459-8548, www.bluewaterventures.org.
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At the same time, elephant seals arrive at Drakes Beach and near the Chimney Rock Headlands on Point Reyes National Seashore and Southeast Farallon Island.
To put it in perspective, the population on the Pacific coast was estimated at around 100 animals in 1890 and then 30,000 in 1970, according to a scientific document published in the Federal Register in 1972. Since the MMPA came into force, the population has grown to around 160,000.
So many elephant seals showed up at Point Reyes during the 35-day state shutdown last winter that they took over the parking lot at Drakes Beach, an amazing sight. Southeast Farallon has become a significant breeding site which, along with high numbers of sea lions and harbor seals, has helped attract whites.
In Año Nuevo, the arrival of the elephant seals has become an event that draws around 50,000 people each winter. Guided walks about 5 km in length are taken along closed paths to see the giants, where males can grow up to 6 meters in length and gather harems of females. Parking is $ 10 per vehicle and tours are $ 7 per person.
Great white sharks
In the 1990s, any great white shark sighting off the coast of the Bay Area was treated as a phenomenon that often made the front page of The Chronicle and topped local television news. At the time, the best guess was that about 200 to 400 whites roamed the Farallones Gulf.
The number is now 2,400, according to a study published earlier this year, which explains the growing number of sightings and encounters.
One of the wildest stories of the year was in Mavericks near Pillar Point Head on the San Mateo County coast. Drake Stanley, who runs a towing and rescue service with a personal watercraft, sighted a four to five meter long great white shark that appeared to be trolling the big wave surfers. At one point the shark was swimming directly below him and within 30 meters of a surfer. Stanley jetted the PWC on the shark, distracted it from the surfer, and then brought nine surfers to shore.
It has been well reported that the increase in marine mammals has likely led to a corresponding increase in whites. Of course, with more elephant seals, sea lions, and seals there is more food for Ol ‘Whitey.
The population expansion of both marine mammals and sharks is a coastal event. On the central coast near San Simeon, San Luis Obispo County, 17,000 elephant seals have been counted. To the south in Montaña de Oro State Park, a surfer was attacked and survived two wounds that required 50 stitches.
With food abundant, it is almost certain that great whites will arrive at their favorite spots this month: the southeastern Farallon Island, Año Nuevo, the Marin Coast off Stinson Beach, the proximity of Chimney Rock on Drakes Bay and the Estuary of Tomales Bay.
Sea otters
The recovery of the sea otter population has stalled just below the threshold for delisting under the Endangered Species Act, and marine biologists believe great white sharks are likely the limiting factor. A sea otter about four feet and sixty pounds is just the right size for Mr. Toothy.
Like so many wildlife species in the 19th century, commercial interests massacred sea otters to extinction; about 150 were discovered by chance in a tree nursery area near Bixby Creek in Big Sur in the 1930s. The population recently passed the 3,100 mark for four years in a row, which qualifies them for removal under the ESA.
Careful pursuit of this proved correct. The latest survey found 2,962 sea otters below the threshold (3,090), according to data from the California Department of Fish and Wildlife.
One limiting factor in otter recovery is “shark bite mortality,” said Linda Carswell, the US Fish and Wildlife Service’s southern sea otter recovery coordinator. Shark predation could “limit their ability to expand into areas where they historically thrived,” she said.
One way to adapt is for otters to migrate in bays and sloughs where they can avoid whites as well as the brunt of winter storms, such as in Elkhorn Slough at Moss Landing. It is common for around 70 to 80 otters to spend winter and spring here. You can often see them by kayak in the Slough and Estuary, or on foot from the adjacent Moss Landing jetty.
The MMPA helped increase the numbers of elephant seals, seals and sea lions. That resulted in more food for great white sharks and much higher numbers. This led to a higher predation in sea otters. Like almost everything in nature, every living being is connected to another.
Tom Stienstra is the outdoor writer for The Chronicle. Email: tstienstra@sfchronicle.com Twitter: @StienstraTom
