[Update, December 22: Aquatic Park has reopened to swimmers, although the National Park Service warns, “Please remember that marine mammals are wild animals, in their natural habitat, and that their behavior can be unpredictable. Give them a wide berth.”
A spokeswoman for the park told Fox News that “park rangers have not observed any unusual marine mammal activity” during the closure period. Even so, be aware that there is always some risk to getting in the water.]
Aquatic Park Cove near Fort Mason remains closed Monday morning after an unidentified, highly aggressive bay animal bit three swimmers last week and necessitated the closure.
The National Park Service announced the swim ban on Friday via Twitter and the NPS website, saying at the time that the closure was scheduled until Monday, December 18. However, Aquatic Park Spokesperson Lynn Cullivan told Curbed SF today that the ban is still in effect as of Monday morning.
Area park rangers will determine when the threat has ebbed, says Cullivan, possibly reopening Aquatic Park as early as later today or keeping the ban in place indeterminately.
An unidentified sea mammal—most likely a seal or sea lion—bit three swimmers in roughly 24 hours between Thursday and Friday, necessitating rescue by SFPD and SFFD divers.
The Aquatic Park Cove has been closed to swimming due to reports of an aggressive marine mammal biting swimmers in the area. The closure is scheduled until Monday, December 18, 2017.— SF Maritime NHP (@SFMaritimeNPS) December 15, 2017
“The park is working with other agencies to identify the animal, and try to determine the reason for this unusual, aggressive behavior,” Cullivan told SF Weekly on Friday. SFFD spokesperson Jonathan Baxter called the attacks “unusual.”
In response to a video of a sea lion dragging a young girl into the water in Vancouver last May, Director of Marine Mammal Research at the University of British Columbia Andrew Tites told the San Jose Mercury News that sea lions are not usually dangerous but that human carelessness can incite aggression.
A 2015 paper in the peer-reviewed journal Wilderness & Environmental Medicine recorded 10 bites by pinnipeds in the San Francisco Bay between 2011 and 2014. Most were harbor seal attacks, with only one positively identified as a sea lion, and there were “no long-lasting consequences from any of the bites.”
“Immediate defense of pups or a mate or hormonal changes during the breeding season are possible explanations for aggressive pinniped behavior,” the paper’s authors say, although December isn’t breeding season for either seals or sea lions. In rare cases, brain diseases may cause sea mammals to become aggressive.