Harbor Seals Get Comfy Off Alameda

ALAMEDA, CA — If you've taken a stroll on Encinal Beach recently, you've probably seen them — the harbor seals on their floating platform.

The platform, dubbed Harbor Seal Island, was built and put there especially for them.

While their streamlined bodies are built for speedy swimming and hairpin turns in the water, East Bay Regional Parks reports "out of the water they move like giant inchworm sausages."

The platform is constructed of reinforced concrete with a Styrofoam core. It was designed by marine mammal expert Dr. Jim Harvey, the director of San Jose State University’s Moss Landing Marine Laboratories. One side is sloped to allow seals easy access from the water.

The platform is not subject to tidal fluctuations or sea-level rise.

It gives the seals a safe place to warm themselves between dips in the cold water of San Francisco Bay.

During the winter, they feast on schools of spawning herring. Otherwise, they're partial to anchovies and bottom dwellers.

The seals are so popular that they have their own Facebook group. There haven't been very many posts recently, but that is likely to change when the pupping season arrives.

While the platform is only 20 by 25 feet, as many as 80 seals have been seen squeezed-together on it at a time.

According to the Marine Mammal Center in Marin County, "In San Francisco Bay, many harbor seals are fully or partially reddish in color. This may be caused by an accumulation of trace elements such as iron or selenium in the ocean or a change in the hair follicle."

While the Marine Mammal Center does not call them "giant inchworm sausages" on land, it can confirm that harbor seals flop along on their bellies, also known as “galumphing.”

Although Harbor Seal Island is close to land, the park service reminds boaters and paddlers to keep their distance. The Marine Mammal Protection Act covers the seals.

If you haven't seen the seals before, grab a pair of binoculars and head to the Bay Trail.

Alameda Point Harbor Seal Monitors Facebook page.

Learn more about the Marine Mammal Center.

Read more about East Bay Regional Parks.