Dozens Of Dead Leopard Sharks Found In California Lagoons

Dozens of leopard sharks have washed up on shores near Redwood City, California over the past month, but city officials and one shark expert are at odds over the probable cause.

Not Enough Oxygen?

The Daily Post reports that Sean Van Sommeran, executive director with the Pelagic Shark Research Foundation in Santa Cruz, suspects the deaths in Redwood Shores were caused by low oxygen levels in ponds as a result of closed tidal gates.

But according to the Daily Post, Redwood City Public Works Director Evan Boyd said preliminary tests on oxygen levels showed that wasn’t the case. He also disputed the tidal gates theory, saying the city found dead sharks both on days when the gates were open and closed.

How Did So Many Leopard Sharks Die?

Van Sommeran is convinced that canals that regulate tide flow may be preventing the sharks, which usually grow about five feet long, from escaping some kind of toxic discharge or other manmade pollution source.

From KCBS:

“We’re mapping and photographing and making contact with the management for the nearby facilities that control the flow of water through those manmade canals,” he said.

Leopard sharks are a non-aggressive species that tend to ignore humans and can live up to 40 years. Van Sommeran said they are very common up and down the California coast.

“They’re a very important feature of the Monterey and San Francisco Bay areas, kind of a signature species of California as well,” he said.

Shark die-offs are not unusual, although Van Sommeran said they are becoming more common.

So far, this die-off appears less severe than more widespread incidents in 2006 and 2007, although it is possible that other creatures succumbing to the unidentified toxin or pollutant could be floundering further from land.

Leopard Sharks Acting Oddly In San Francisco Bay

Meanwhile, the Richardson Bay Audubon Center & Sanctuary has noticed a few leopard sharks in the San Francisco Bay, just a few miles from Redwood City, that seem to be either sick or acting oddly lately. Could this be connected to those recent deaths?

You can see a video of these sharks by clicking here.


Photo Credit: bikehikedive via Creative Commons


William C
William C5 months ago

Thanks for caring.

W. C
W. C5 months ago

Terrible, thank you for the information.

Waltraud U.
Waltraud U6 years ago

If the reason is already found - as Sue H. - on another part of the earth start the next disaster.
Our authorities do not make their homeworks.

Chris M.
Chris M6 years ago

Incredibly sad...

Isabel Araujo
Isabel Araujo6 years ago

So sad, indeed.

Judith N.
Judith Night6 years ago

It sounds like nerve damage when an animal acts oddly and that they have been poisoned; their behavior mimics flickers acting oddly due to having ingested pesticides while searching for bugs in trees, direct nerve damage to the animal from human interference with nature. The sharks may have ingested something pollutants causing deadly nerve damage. Has this possibility been explored? What chemical plants are spewing out into the ocean around leopard shark habitat? Is there a leak in a raw sewage dump? This has happened before; there is a pattern here; something is definitely going on.
You would think of course, this was looked for immediately; but then, did anybody think about where the spent rods would go when they cooked up these splendid nuclear power plants? Or how the salmon would spawn when they created all those dams? Or how genetically modified grains would then spread and infect natural grains? No point in continuing here.

Robyn B.
Robyn B6 years ago

Humans are being shown on a daily basis the consequences of our poor water management policies. When will we learn that the solution to pollution is NOT dilution!!!

Kevin Blakely
Kevin B6 years ago

How do you read this and then vote yes the earthquake has something to do with it? Actually, WHY even ask the question. It's clear pollution and poor water management in California is a problem... not earthquakes in Japan. Wow, talk about denial.

Yea, I'm sure there's a shit load of stuff dying in Japanese waters now... but it stupid to attempt to link that to ALL the problems we have created in our oceans.

Typical "pass the buck to the next generation" mentality.

Jonathan Y.
Jonathan Y6 years ago

If you've ever seen the pollution in S.F. Bay or Oakland, you wouldn't be surprised. Amazing anything can live in there. Plus these sharks are scavengers as well as predators and feed along the bottom.

Worrying though, because sharks are pretty tough fish and generally resistant to disease. If something in the water is killing the sharks humans need to find out what it is fast.

Patricia A.
Patricia A6 years ago

I think God can see now that putting humans in charge of this planet was a mistake! Animals can co-habitate with each other. We should be learning from them not destroying them and our planet. I hope they find the cause for their deaths and so many more in our waters all over the world.