Science/Health

Mysterious death of more than hundred leopard sharks recorded in California: What causes the sharks' eradication

By Mharia Emmareen / 2017.05.09
Hundreds of leopard sharks die off along the San Francisco Bay area in California.

More than a hundred dead leopard sharks or Tiburon died in San Francisco Bay, California and scientists are baffled with the cause of their death. To date, it would be the largest die-off recorded this year in a span of six years.

Not only leopard sharks or Tiburon died but also other shark species, bats rays, and halibut have been discovered. Since the middle of March, different marine animals perish near the shorelines of Alameda, Berkeley, Foster City, Hayward, Oakland, Redwood City and San Francisco. Other dead marine species such as sharks and rays were also sighted in the coastal waters of Bolinas in the Marin County.

According to SFGate, this year would be twice in a row where a huge number of San Francisco Bay's most bountiful shark, the leopard sharks, are dying during spring in time when pups are born. Marine biologists are certain that leopard sharks got the toxin from stagnant saltwater where marshes grow. It could be also from sloughs and at the back of the man-made lagoon gates in Redwood City and Foster City.

Senior fish pathologist for the California Department of Fish and Wildlife, Mark Okihiro said in a written synopsis, "My estimate is that several hundred sharks have already died." He added that "There appears to be no leveling off of shark deaths in the bay and I am still getting reports from locations throughout the South Bay regarding dead or dying leopard sharks."

Since 2011, this year's recorded die-off has been the biggest leopard sharks mortality occurrence. More than a thousand dead sharks have been counted in the Redwood Shores Lagoon situated in the Marin County. Since leopard sharks do not possess lungs they sink automatically to the sea floor after dying. This adds to the theory that the figures of leopard sharks that were washed up on shorelines and beaches are much lesser than the actual death population, abc News reported.

Leopard sharks (Triakis semifasciata) are a houndshark species in the Triakidae family. This shark species is generally found in North America's Pacific coastal lines. The Tiburon, as called in Spanish is believed to grow as much as six feet long and lives up to 50 years.

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