Researchers are trying to figure out why hundreds of leopard sharks have been washing up dead the past 12 weeks on the shores of the San Francisco Bay.
The San Francisco Chronicle reports fish pathologist Dr. Mark Okihiro released findings on Wednesday that show a common pathogen was in three sharks examined so far.
Sean Van Sommeran, executive director of the Pelagic Shark Research Foundation, believes the source of the infections is the city's use of tide gates near inland waterways.
U.S. & World
Leopard sharks come into shallow waterways to mate during the spring and summer, so they often get trapped when the tide gates close.
When the gates reopen, the rotting and decaying sharks are released back into the bay, where Van Sommeran fears they could be contaminating more animals.