How Come Sharks Are Washing Up Dead On San Francisco Bay?
By Kalyan Kumar
Large scale deaths of leopard sharks in San Francisco Bay have alarmed environmentalists. This is in contrast to the good times enjoyed by sharks in southern California in terms of good food and enduring climate.
Large scale deaths of leopard sharks have been reported in San Francisco Bay. The death toll running into thousands was the highest in last six years and has rightly alarmed environmentalists.
Dead sharks have been washing up on the shores of the San Francisco Bay for many weeks.
According to reports, hundreds of dead sharks have been found on the beaches from San Mateo to Bolinas. The die-off has been unprecedented as far as the striped fish is concerned.
The dead sharks were washed up since March second week at the shorelines of Redwood City, San Francisco, Hayward, Foster City, Alameda, Berkeley, and Oakland, according to researchers.
Sean Van Sommeran, executive director, Foundation said the death toll will be thousands. This was the highest mortality since 2011.
According to experts, the shark deaths in San Francisco Bay shores were the fallout of sharks consuming poisoned food in stagnant salt waters. The concern was fuelled by the high numbers and death of newborns and mature adults.
Chemical Waste From Drains Poisoned Sharks
Pelagic Shark Research Foundation blamed the shark deaths to debris, trash, and chemical waste piled up in Bay Area from drains and waterways whose influx exacerbated the poisoning of creatures.
The closure of tide gates inside the bay to guard against flooding also trapped sharks in the bay and made them victims of the toxic runoff.
"This is an issue of San Francisco Bay sharks and associated wildlife being exposed to toxic watershed ... due to Tide Gate entrapment and subsequent discharges into the San Francisco Bay," the center said in a Facebook post.
Closing Of Tidal Gates Trapped Sharks
The leopard sharks picked up more toxins in stagnant saltwater marshes near the gates of the Foster City and Redwood City lagoons.
"My estimate is that several hundred sharks have already died," said Mark Okihiro, the senior fish pathologist for the California Department of Fish and Wildlife.
Sommeran also noted that the problem becomes acute as leopard sharks move into the shallow waterways to mate and breed during the summer and spring.
When the tidal gates are closed ahead of heavy rains to avoid extra precipitation and flood, fungal blooms develop in the stagnant water exhausting oxygen and further poison the fish.
Sommeran said rainy season also adds to the damage by washing out accumulated toxins in the ground into the bay.
Shark attack In Southern California
Meanwhile, commenting on a severe shark attack in coastal California on Leanne Ericson of Vista, director of the Shark Lab at Cal State Long Beach Chris Lowe said the shark that attacked the Ericson may not be a full grown adult. It must have mistaken her for food. However, he added that there is no need for panic and the coastline is very safe.
The young shark bit off a portion of Ericson's leg while swimming off San Onofre State Beach. She underwent multiple surgeries after heavy loss of blood.
"Accidents do happen and that's what we think these are. There's no indication these sharks have any penchant for eating people," he added.
Obviously, in California coast, sharks are thriving with abundant food and warming waters. White sharks arrived in Southern California after their winter sojourn off Baja California.
Baby white sharks cannot withstand temperatures above 80 degrees. That is why they have made Southern California the perfect abode to live from late spring to mid-fall.