A History of the Sea Lions at PIER 39

Historically, California sea lions have always been observed on Seal Rock, North of Ocean Beach, below the Cliff House Restaurant in San Francisco. They come into the San Francisco Bay to feed, sleep at the surface of the calmer bay waters, and infrequently haul out on land or docks. However, in September 1989, sea lions began to appear consistently at PIER 39's K dock. The dock had recently been refurbished and for a period of time no boats were docked there, leaving large open spaces where sea lions could easily haul out. When the boats returned, no real effort was made to discourage the sea lions from hauling out. Also, only half the dock was filled with boats. The slips closest to the jetty opening were "guest docks" reserved for day or overnight rental. At the end of September, 1989, only 6 to 10 California sea lions frequented K dock.

As previously mentioned, it is normal for California sea lions to be in the Bay, especially during the winter months when herring are an abundant food source. By mid-January 1990, there were about 150 sea lions at PIER 39. As the number of sea lions at PIER 39 increased, the number at Seal Rock decreased. What made them change their preferred haul out is unknown. People often speculate that the earthquake on October 17, 1989, caused them to abandon Seal Rock. At that time, however, the sea lions were already frequenting K dock. No one can prove the influence, if any, the earthquake had on the sea lions haul out choice. It is certain that K dock provides a safer place to rest, as sea lions' predators (great white sharks and orcas) do not enter the bay. The docks are easy for sea lions to jump onto, and the docks go up and down with the tides. Sea lions resting on rocks must climb up and move as the tide rises, or abandon their spot altogether if it becomes submerged.

Another theory contends that the presence of fishing boats docked in the guest slips at K dock after the earthquake attracted more animals. However, each December-January, when the herring spawn in the San Francisco Bay, a few fishing boats customarily dock at PIER 39, and had never before attracted a permanent group of sea lions.

At first, the sea lions were viewed as a nuisance and rightly so; the owners of the 11 boats docked on K dock had to get to their boats while trying to avoid wild animals weighing in at 100 to 1000 pounds. The safety of the boat owners was a definite concern. Other concerns included the noise, the stench and damaged property. At least one resident from Telegraph Hill called about the noise! PIER 39 sent out its first press release about the "invasion" on January 19, 1990. The media played up the problems and dangers, of course, adding humor to the situation by referring to the "Boys Of Blubber," "Herring Gobblers," "Guests From Hell," and "Bold, Sexy Sea Lions Begging For Handouts."

PIER 39 contacted The Marine Mammal Center for advice and information. The Center recommended the use of herding boards for people walking on the docks, and indicated that moving the boat owners from K dock would be the safest precaution. We provided general information about sea lions and gave what insight we could about why they came and if they would stay. In February, 1990, there were about 250 sea lions, and by March the population was more than 400. At this time, PIER 39 had relocated the boats from K dock to other locations in their Marina. The dock was officially closed to the public and set aside for the sea lions.

The population of sea lions at PIER 39 began to decline after March 1990. The Marine Mammal Center organized a pilot docent program that began in June, to educate tourists about sea lions. By then, however, all the sea lions had migrated South to their breeding grounds on the Channel Islands off the Coast of Santa Barbara, California. The Center's docent program was put on hold until, or rather "if," the sea lions returned. No one was sure they would return. However, the experts felt that, being creatures of habit, the sea lions would be back.

They reappeared the first week of August 1990. First 6, then 9, and finally 50-100 animals hauled out in September and October. The population increased to a peak of more than 500 sea lions in late January 1991, then began to decrease. By July (the peak of the tourist season), there were few sea lions. Since 1996, there has also been a peak in numbers in May and early June, just prior to the breeding season, The highest numbers are now seen in late summer and fall. This population pattern has occurred most years since. The last official high count was 1,139 sea lions on September 3, 2001.

When these high numbers occur, some sea lions haul out on neighboring J dock. This is usually temporary, and not a serious problem for boat owners. Sea lions that haul out there may be sick or injured. The Marine Mammal Center has had some success in rescuing these animals.

The weight of the sea lions, often thousands of pounds, caused K dock to submerge, become water-logged and eventually fall apart. PIER 39 initially built twelve 10' x 12' floats, which were placed between the fingers of K dock. PIER 39 employees thought that if more haul out space was provided, the pressure on the dock would decrease. Sea lions continued to haul out on the dock and the floats. The construction of new floats was discouraged by The Marine Mammal Center, because more space could attract even more sea lions. In the summer of 1995, the original K dock was removed, as it was a hazard to boats. More floats were moved in to replace the dock.

Nearly 40 sick or injured sea lions have been rescued by The Marine Mammal Center at PIER 39. More rescues have been attempted; however, a dock full of sea lions presents one of the most difficult rescue situations. The dock is often wet, slippery and unstable. If the rescue team does not have access to a boat, then they can only approach from one direction, walking down the dock. If the sea lion sees them and is disturbed, it can easily and quickly roll over into the water, or it may attack out of fear. If there are more than a few sea lions scattered on the dock besides the one to be rescued, the rescue team has little chance of approaching their chosen sea lion unnoticed. Many rescues have been attempted at K dock, but only one has been successful so far. These rescues can only be attempted by boat, requiring volunteers to jump in the water to assist, which can be very dangerous.

One of the first sea lions to haul out at PIER 39 was famous for his ability to avoid being captured. He was christened "Flea Collar." He was a large adult male, estimated to weigh at least 550 lbs., with plastic strapping around his neck, which cut into his blubber. We made a few attempts to restrain him, including the use of a floating net, so the "collar" could be cut off. Unfortunately, none of the rescue attempts were successful.

"Flea Collar" and other large sea lions with similar entanglements have been observed every year. All appear to be entangled with packing straps or fishing line, or have fishing lures hooked on their heads. Hooks and lures most often will work themselves off; rescue is usually not required. We will attempt a rescue if conditions permit. Most entangled large sea lions, like "Flea Collar," are still fat and sleek. Rescuing them is much more dangerous compared to rescuing smaller and more debilitated sea lions.

Each year, we recognize individual sea lions that return, from tags on their front flippers or distinctive scars. Sea lions with numbers branded on their sides, or red or yellow tags, were marked by researchers. Orange tags indicate rehabilitated sea lions. The tag number tells us whether it was a patient at The Center or one from another rehabilitation facility. Some notable tagged sea lions are Barge (left tag number 5224), who was released from The Center in October, 1984 and observed at K dock until 1993; and Bingo (left tag number 9217), who stranded in April, 1992. Bingo had a gill net under his chin, cutting so deep that it severed his trachea. He was breathing from the hole in his trachea. After surgery at The Center, he successfully recuperated and was released in August, 1992. The first confirmed sighting of Bingo at PIER 39 was February, 1993. He is frequently recognized by the distinctive scar under his neck and the orange tags. In 2001, at least two orange-tagged female sea lions with tags on their right flippers were sighted on several occasions.

Before 1995, there were a few observations of a lone harbor seal hauled out among the sea lions. Each harbor seal tended to haul out at the far end of the dock, keeping as much distance as possible between itself and the sea lions, or it hauled out in July when the sea lions were gone. Every spring since 1999, a subadult male harbor seal has been observed hauling out on K dock, among many other sea lions. This is unusual for this shy, skittish species.

In the spring of 1991, two experienced docents described what could have been a juvenile Steller sea lion hauled out at PIER 39. In August 1993, the first confirmed sighting of a Steller sea lion at PIER 39 was recorded. The subadult male Steller was later observed on various occasions. As big, if not bigger than the largest adult male California sea lion, he was a very light brown-auburn in color. His head had no crest but was broad, boxy and bear-like. He did not seem to mind the California sea lions. He even allowed young ones to sleep next to him, resting their heads on his back. He appeared in good health. It is assumed (and very likely) that each sighting of a Steller since 1993 was of the same individual. Each year he is larger and his adult characteristics are more pronounced. He is usually observed in late summer and fall, periodically in the winter.

Using volunteers and staff at The Marine Mammal Store and Interpretive Center, we are now able to monitor the sea lion population daily, and provide information about them to visitors from all over the world. Our Science Department has conducted a behavior study and a study of the sea lions' diet through fecal analysis. Sighting former patients adds to our information about the success of our rehabilitation efforts. Our continued monitoring of this wild population of California sea lions will provide valuable knowledge about population dynamics, diurnal and yearly patterns, feeding habits, and behavior. We also are learning about interactions among California sea lions, with other species, and with the nearby human population.

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