A sea lion that was rescued from a South San Francisco canal was euthanized Wednesday after wildlife caretakers discovered it had an untreatable case of toxic poisoning.
Around 6 a.m. Monday, a passer-by noticed a sea lion in the Colma Creek Drainage Canal on the 400 block of North Canal Street, South San Francisco police Cpl. Bruce McPhillips said.
The sea lion, which was between 4 and 5 years old, “appeared to be in distress,” McPhillips said.
Firefighters from a station across the street from the canal responded and observed the animal until Marine Mammal Rescue Center personnel arrived from Sausalito about 1:30 p.m., he said.
Rescue Center personnel located the 8-foot sea lion at the bottom of the muddy canal, about 50 feet down, and used a crane to lift the animal to street level.
On Tuesday, the sea lion was resting in Sausalito, but it was still experiencing significant respiratory problems, said Mieke Eerkens, a spokeswoman for the Marine Mammal Center.
The sea lion — named Station 61 in recognition of the efforts by the nearby firefighters — suffered from domoic acid poisoning, likely contracted by eating a fish that previously fed off algae blooms, Eerkens said. Unlike certain aquatic species, sea lions are not immune to the high level of toxins present in some forms of algae, he said.
Eerkens said the center suspected the 235-pound sea lion was suffering from the poisoning because the toxin usually affects the part of the brain that controls navigation, which would explain why the animal was in the inland canal. The sea lion also suffered a seizure Wednesday morning, another side effect of domoic acid poisoning.
“Station 61 would have suffered a real painful death if he wasn’t euthanized,” Eerkens said. “He wouldn’t be able to forage, and he would drown if he suffered a seizure underwater.”
The algae blooms that ultimately led to the death of the sea lion are natural, but have been growing recently in the Pacific Ocean, Eerkens said. There are some theories — still unproven — that the growth is the result of global warming or agricultural runoff, he said.
In July, a sea lion found in a Santa Clara aqueduct was euthanized after also being diagnosed with domoic acid poisoning.
Bay City News contributed to this report.