Mosquitoes Blamed For Captive Killer Whale Deaths


Written by Stephen Messenger

In the open ocean, healthy killer whales live free of any natural predators — but in captivity, even the smallest of insects pose a lethal threat to these majestic giants.

According to the Whale and Dolphin Conservation Society (WDCS), new evidence suggests that in recent decades at least two orcas housed at SeaWorld parks perished due to mosquito-borne illness from West Nile and St. Louis encephalitis viruses. The findings raise renewed questions about the appropriateness of keeping large aquatic mammals in such restrictive holding tanks — which experts say, contributed to the transmission of the diseases.

Courtney Vail, campaigns manager for WDCS, says that killer whales in captivity are prone to spending too much time floating, or “logging”, due to the limitations of their enclosures. These unnatural restrictions, and the resulting coping behavior, make orcas in captivity more susceptible to insect bites and the threat of disease:

“We continue to be astonished at the serious information that is being discovered about the condition of orcas in captivity, and that hasn’t yet been shared with the public,” says Vail. “I think it is safe to say that no one would have thought of the risks that mosquitoes might pose to orcas in captivity, but considering the amount of time they unnaturally spend at the surface in shallow pools at these facilities, it is yet another deadly and unfortunate consequence of the inadequate conditions inherent to captivity.”

Former SeaWorld trainer, Dr. John Jett:

“Logging was commonly witnessed while I was at SeaWorld, especially at night, which provided a static landing platform for mosquitoes. Free ranging orcas, conversely, are on the move and not exposed to mosquitoes. They don’t remain still long enough and mosquitoes are weak fliers, limited to coastal areas. This information is an important introduction to a topic sure to raise eyebrows.”

So far, the experts have identified two orca deaths at SeaWorld parks in Orlando and San Antonio resulting from mosquito-borne viruses, though there may be more as several dozen animals remain in captivity throughout the world. The WDCS hopes to raise public awareness about these threats as they advocate for the release of killer whales.

This post was originally published by TreeHugger.


Related Stories:

Over 260 Dead Dolphins Wash Up In Peru

Are SeaWorld Orcas Illegal Slaves?

Citizen Scientists Needed to Analyze Whale Calls


Photo from congvo via flickr


Susan Oliver
Susan Cytko5 years ago

and pigs might fly.

Waltraud U.
Waltraud U5 years ago

People need to vote unacting authorities and such „BASTARDS“ acting in unhumane ways out of their occupations!

Robert Miles
Robert Miles5 years ago

Hummingbirds are known to make flying insects a major part of their diet. How much would it help to require all places in the Americas with captive whales or dolphins put up attractions for hummingbirds nearby? Or do we first need more research on how likely hummingbirds are likely to eat mosquitoes rather than other insects? Hummingbirds are not found in continents other than the Americas, and do not do well in captivity.

Diana P.
Diana P5 years ago

How about the celebrities raising some awareness about children right here in their own back yard. So many American children need a break also. Not just the kids overseas.

Diana P.
Diana P5 years ago

These, like all other animals need to live in their own environment not caged and kept from where they belong. Now that you have them teach them to hunt so they can be set free

Mandy Harker
Mandy H5 years ago

I'm surprised that mosquitoes can actually get their stinger though the whales skin since they're so much bigger then a mosquito. Thank you for the information, it's very interesting.

Judith H.
Judith H5 years ago

Time to ban keeping these majestic animals in captivity!

Past Member
Past Member 5 years ago

troppo belle ,lasciamole libere

Anita Wischhusen
Anita Wisch5 years ago

The sad thing is that captive born Orcas CAN'T be released back into the wild. They haven't been taught social skills like how to catch wild fish, where the best feeding grounds are, migration routes, etc. The best thing we can do is DEMAND that Sea World no longer breed orcas, and let them live out their lives with no future gererations being raised in captivity.

Mrs M.
Linda M5 years ago

That's a terrible loss.