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Seals gathering like I’ve never seen before. What to know about these ‘fascinating’ creatures

Pinniped, according to the Marine Mammal Center, located near the Marin Headlands, means fin or flipper-footed and refers to the marine mammals that have front and rear flippers.

This group includes seals, sea lions and walruses. I was operating one of the PG&E’s marine monitoring vessels last Friday when I saw something I never before have since I started boat operating there in 1992 as we were leaving the Diablo Canyon Marina heading toward open water. The entire west breakwater was covered with sea lions.

These high sea lion impulse events where they gather in huge groups called herds do happen from time to time in ports and harbors. These herds can reach over 1,000 individuals and can cover entire docks, piers and even boats, but researchers aren’t quite sure why they do this?

We do know that since 1972, when the Marine Mammal Protection Act became law, pinniped populations have dramatically grown, according to Mike Harris, a sea otter biologist and senior environmental scientist with California Fish and Wildlife.

Another factor in the pinniped population rise is the number of available haul-out sites where they rest and give birth. Hundreds of years ago, grizzly bears and wolves reduced the number of these sites along the California coastline and forced them to occupy offshore monuments, like islands, rocks and exposed reefs.

Along the California Coastline, the most common types of pinnipeds are California sea lions, harbor seals and elephant seals that can be readily seen or heard. How can you tell the difference between them? Sea lions have rotatable rear flippers and long fore flippers, which means they can “walk” on land and even climb.

Just north of Diablo Canyon Power Plant is Lion Rock, a relatively large island that rises about 100 feet above sea level. It is home to hundreds of sea lions and numerous cormorants and pelicans that flourish there. Sea lions reside on the top of Lion Rock and can be heard from miles away; their piercing barks resonate.

Lion Rock 2.jpg
Seals on Lion Rock, an island just north of Diablo Canyon Power Plant. John Lindsey Special to The Tribune

Unlike harbor seals, sea lions have external ears flaps. They can live between 15 to 20 years in the wild, and males can weigh up to 1,000 pounds, while females are smaller and weigh an average of around 200 pounds. Harbor seals look like sausages when hauled out on rocks.

Because they are relatively small compared with many other marine mammals, they need to rest and warm themselves in the air on exposed rocks or beaches. They cleverly use the turning tides to place themselves on top of wash rocks or reefs. With un-rotatable rear flippers, they can’t walk or climb on tall wash rocks, boats or docks, but they move on land by galumphing (wriggling and rippling on their bellies in a bouncy-like motion).

They are not as loud as sea lions but have a vast diversity of sounds that included barks, grunts, growls and tonal honks that sound like something out of Star Wars. Under the ocean’s surface, you can hear them roar. They have big puppy dog eyes and large whiskers but don’t have external ears.

In the water, they are graceful and highly curious; it’s a joy to scuba dive with them. Scottish folklore refers to these seals as selkies. Legend says that selkies can turn human for a short time during the “seventh stream” or spring tide. However, we do know this, male harbor seals can live between 20 to 25 years, while females can reach 35 years.

They all have distinctive markings and colors from nearly silver-white to grey to brownish tan to black. These markings allow marine biologists to track the comings and goings. They love areas protected from adverse oceanographic conditions like big sea or swell events near their foraging grounds.

I have come to recognized different individual seals over the years at the Diablo Canyon Marina. Elephant seals are enormous; males can reach over 5,000 pounds. Over my time at the power plant, I and have seen them in the Diablo Canyon Marina, but their main haul-out location is along the San Simeon shoreline near Hearst Castle where you can see them year-round.

One of the more fascinating facts about these pinnipeds is they can dive to over 5,000 feet and hold their breath for more than 100 minutes.

To learn more about these magnificent creatures and where to see them, please visit Friends of the Elephant Seal at www.elephantseal.org/. Please remember, if you a seal behaving abnormally, keep your distance from the animal and call The Marine Mammal Center at 415-289-7325.

John Lindsey’s column is special to The Tribune. He is PG&E’s Diablo Canyon marine meteorologist and a media relations representative. Email him at pgeweather@pge.com or follow him on Twitter: @PGE_John.
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