Large Numbers of Leopard Sharks Die around San Francisco Bay

Leopard shark

Researchers discovered hundreds of dead leopard sharks in the middle of the mating season

Researchers discovered an alarming number of dead leopard sharks along San Francisco Bay. They declared that this was the largest number of dead specimens they had recorded since 2011, when they found more than 1,000 dead sharks on the shores of Marin County.

The number of dead leopard sharks is constantly increasing

Scientists and pathologists have already started estimating the number of dying leopard sharks. They suspect that a few hundreds have already died, while many others are still struggling to stay alive. The senior pathologist at California Department of Fish and Wildlife made the estimates but, unfortunately, he is afraid it is not over.

“I am still getting reports from locations throughout the South Bay regarding dead or dying leopard sharks.”

Leopard sharks do not have lungs. Therefore, when they die, they do not remain floating on the surface of the sea, but they sink. This is why it is hard to discover the exact number of dead sharks. The situation is not encouraging at all, since there is already a big number of reported deaths, and the waters are probably hiding more dead animals.

Massive die-off during the mating season

Researchers have started noticing the worrying numbers of dead leopard sharks seven weeks ago. This puts them in great danger, since we are right in the middle of the mating period. During these periods, sharks come in shallow waters, where they mate and pup.

Researchers suspect that they got caught in the artificial lagoons in the area when there is low tide. In such situations, cities close the tide gates so that, if it rains heavily, the rain water would not mix with the tide water and it would not cause floods.

These artificial lagoons contain some fungal blooms which consume oxygen from the water. If sharks get caught here, they are at risk of getting poisoned by the blooms and die. Therefore, all leopard sharks in the area are at risk during the mating period, and researchers are trying to figure out a way to protect them.
Image Source: Wikimedia Commons