Harbor seals make use of commercial dock in Seaplane Lagoon

Over the years, harbor seal observers on the former Alameda Point Harbor Seal Monitors Facebook page often asked, “Do we need another harbor seal float?”  It appears the seals have provided their own answer. 

December is when the numbers of harbor seals start increasing at Alameda Point in anticipation of the winter herring spawning in the vicinity.  The influx of seals leads to overcrowding on the specially built float near the ferry maintenance facility and Bay Trail.  It has been happening since the harbor seal float was deployed in the summer of 2016.  Again this December, the float has been fully occupied with as many as 75 seals (verified by numbering a printed photo) during part of the day and not an inch to spare.

Harbor seals arriving at Alameda Point this December found an alternative spot to the overcrowded float when they ventured into the nearby Seaplane Lagoon.  Their additional haul-out location is on a plastic commercial dock owned by Saildrone, the maker of autonomous battery-powered boats capable of gathering marine scientific data around the world.  Saildrone vessels, manufactured in a hangar on West Tower Avenue, can often be seen moored in their leased space in the Seaplane Lagoon.   

The main harbor seal float was jam-packed with harbor seals on December 7-8, and there were between 11 and 13 seals on Saildrone’s plastic dock in the Seaplane Lagoon. 

Much of the cost for another float has already been paid for in the design and construction of the mold for the first one.  The Water Emergency Transportation Authority (WETA), which operates the San Francisco Bay Ferry system, provided the funding for construction and deployment of the harbor seal float after wildlife advocates lobbied to have them provide a new haul-out platform in place of the one they planned to demolish for their facility.  WETA is responsible for maintaining the seal float for the 60-year life of the ferry maintenance facility lease at Alameda Point.  

Moss Landing Marine Laboratories Director, Dr. Jim Harvey, was hired as a consultant by WETA to help with design and location of the new seal float.  He accurately predicted that ferry traffic would not affect the seals’ behavior. 

Barely six months after the harbor seal float was deployed there was talk among harbor seal enthusiasts of a second float.  The San Francisco Bay Conservation and Development Commission (BCDC), which issued the permits for the seal float and ferry maintenance facility, was reportedly amenable to permitting a second float.  But they first wanted to see what the impact on seal behavior would be once the 12-berth ferry maintenance facility was in operation in 2018. 

“BCDC staff would certainly meet with the City to discuss a proposal for a second haul-out,” said Erik Buehmann, permit analyst with BCDC, at the time.  “Any new haul-out should be planned in consultation with WETA and incorporate the opinion of experts, such as Dr. Harvey.”  

To date, there has been no organized effort to deploy a second harbor seal float at Alameda Point.

The harbor seal float is the only place in the East Bay between Yerba Buena Island and Newark where large numbers of harbor seals can get out of the water to rest and warm up, which they do for about half of every day.  And they can do so regardless of tide levels. 

Besides benefitting the seals, the proximity to the shoreline also offers a good opportunity for passersby and educational groups to easily view large numbers of seals.  The Alameda Point site is one of the few places on San Francisco Bay where harbor seals can be viewed from a public trail. 

This is one of the best times of the year to observe the seals, and now there is another opportunity for visitors to view the seals from the shoreline of the Seaplane Lagoon.

We reached out to Saildrone for a comment on the harbor seals utilizing their floating platform, but they declined to comment.

Originally published on the Alameda Post.