The California Department of Fish and Wildlife isn’t dedicating any funding toward determining the cause, says resources are needed elsewhere
October 5, 2017 — As many as 2,000 leopard sharks have mysteriously died in the San Francisco Bay over the past few months. The California Department of Fish and Wildlife says determining the cause is not a priority for the state since the sharks are not threatened or endangered, however, scientists say additional research and resources are crucial since the threat is now believed to be preying on other marine life.
“This year is unusual in that there has been a large number of other species that have also been dying,” said Dr. Mark Okihiro, a research scientist with the California Department of Fish and Wildlife. “This pathogen can tackle a variety of different species … we’ve had a much more diverse group of fish that have been found dead in the San Francisco Bay.”
At least 500 bat rays, hundreds of striped bass, 50 smooth-hound sharks and about 100 halibut died in the bay between February and July, according to Okihiro’s estimates.
Tiny Organism Blamed for Massive Shark Die-Off
Similar shark deaths in the area date back 50 years and have gone unexplained. Okihiro, however, now believes a parasite may be behind the mysterious die-off that has plagued the Bay Area.
“We’re pretty confident at this point,” Okihiro said. “It’s called Miamiensis avidus … it’s a small single celled organism. It’s very similar to the common amoeba.”
Okihiro regularly performs necropsies on stranded sharks found along the bay and says researchers at UC San Francisco helped him identify parasite DNA in a large number of those shark samples.