What's eating the brains of sharks and rays in California?

 
Between February and July, there have been a lot of incidents, where dying or dead sharks and rays have washed up on beaches in San Francisco bay. What is causing them to die?


According to an article in National Geographic, CDFW senior fish pathologist Mark Okihiro, Joseph Derisi, an expert on the genetics of infectious diseases at the University of California, San Francisco and Hanna Retallack, an MD-PhD graduate student have found the answer.

Their headline reads : "Mysterious Brain-Eating Shark Killer Identified, Though Questions Remain"

  
It looks like the culprit is "a well-known fish-killing parasite called Miamiensis avidus."

The article further states: This appears to be the first case, Retallack said, of Miamiensis avidus infecting wild sharks. It’s noteworthy, she added, because sharks are evolutionarily quite different from the bony fish that have previously been known to suffer infections. 

Read the entire article here

Cheers,
Martin Graf
CEO Shark Diver

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at staff@sharkdiver.com.

Mayans Respected Sharks 1600 Years Ago?

Shark Gods 1600 years ago

1600 years ago the ancient Mayans had a thing for sharks, at least when it came to representing them as Sun Gods.

National Geographic has the scoop and some pretty nifty images this week with a new temple discovery in Guatemala.

Nice to see even 1600 years ago people revered the shark, or...was this a conservation cult for sharks where individuals used these animals to their own grandiose media ends?

From Nat Geo:

Some 1,600 years ago, the Temple of the Night Sun was a blood-red beacon visible for miles and adorned with giant masks of the Maya sun god as a shark, blood drinker, and jaguar. Long since lost to the Guatemalan jungle, the temple is finally showing its faces to archaeologists, and revealing new clues about the rivalrous kingdoms of the Maya.

About Shark Diver. As a global leader in commercial shark diving and conservation initiatives Shark Diver has spent the past decade engaged for sharks around the world. Our blog highlights all aspects of both of these dynamic and shifting worlds. You can reach us directly at sharkcrew@gmail.com.

Michael Aw - Some Kind of Awesome

Photo by Michael Aw

It's 2011 and the more cynical among us might imagine a world that has been picked over, where true adventures and underwater discoveries are relics of the past.

Not so if you happen to be Michael Aw and we happen to be big fans of his work.

Michael's expose in this months National Geographic tells the tale of regional fishermen in New Guinea who interact with Whale Sharks in surprising ways.

Run, don't walk, to the nearest Barns and Noble if you are not fortunate enough to get Nat Geo delivered to your doorstep and pick up this months magazine.

This is about as good as it gets and kudos to Michael for the great work.

Whale Sharks Killed, Displaced by Gulf Oil?

When the BP Gulf Oil Spill began, soon to become Americas biggest oil disaster, this blog quickly focused attention on a small research team out of the Gulf Coast Research Laboratory who had been studying Whale sharks in the region for the past several years.

Their research site turned out to be an oily ground zero.

Our coverage, with the help of several other blue bloggers, lead to timely mainstream media pieces that picked up this unfolding eco disaster and followed it to its frustrating conclusion.

Or was it?

National Geographic has a first rate follow up about the effects millions of gallons of spilled oil has had on these gentle giants in the region and is a must read:

Though much of the Gulf oil has disappeared from the surface, the spill isn't going away—and scientists are still trying to uncover the extent of its invisible effects on Gulf wildlife.

(Read about the Gulf oil spill in the October issue of National Geographic magazine.)

For instance, certain toxic ingredients of oil—and even the chemical dispersants used during the cleanup—could potentially cause long-term problems for whale sharks and many other species. Those may include compromised endocrine or immune response systems, scientists note. (See related blog: "Gulf Seafood With a Side of Oil Dispersant?")

Whale sharks filter a lot of water through their mouths and gills—almost 160,000 gallons (605,000 liters) of water an hour—as they feed on tiny plankton and fish.

Complete Story.

Giant Stingrays-Elasmo Thai

When this came across our desk this morning all we had to say was Holy Cra%@!

Yes this is what you think it is, and no this has not been photoshopped. Researchers and fishermen in Thailand landed a simply monster freshwater stingray-what they did with it after this photo finish is anyone's guess.

April 29, 2008—Recreational fishers and biologist Zeb Hogan (wearing cap) hold a live, 14-foot-long (4.3-meter-long) giant freshwater stingray the fishers caught in the Bang Pakong River in Chachoengsao, Thailand, on March 31, 2008.

After weeks of combing remote Southeast Asian rivers for giant freshwater stingrays—possibly the largest freshwater fish in the world—Hogan finally found the creature near a Thai city. To his surprise, she gave birth soon after capture. (Read full story.)

There are accounts of freshwater stingrays growing as large as 1,000 pounds (450 kilograms), which could make them the largest freshwater fish in the world, Hogan said. Hogan runs the National Geographic Society's Megafishes Project, an effort to document 20 or so freshwater giants.

The giant river rays are extremely difficult to catch, as they bury themselves in mud when hooked. They routinely break fishers' lines and bend finger-size hooks straight to escape capture.The ray's deadly barb, located at the base of its whiplike tail—and wrapped in a cloth in this picture—can easily puncture skin and bone.