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Mosquitofish vs. West Nile: Good idea gone bad?

By Gary Bogue
Tuesday, September 30th, 2008 at 7:10 am in Mosquitoes, Mosquitofish, West Nile virus.

Good news, or bad news?

There was a story on Sept. 26 in the San Jose Mercury News by Lisa M. Krieger: “Hungry mosquitofish — the defense against West Nile — is also munching threatened frogs.”

The story explains that mosquitofish dine on larval mosquitoes as planned when county vector control people distribute thousands of the fish to residents for free to fight skeeters in backyard pools and ponds … BUT … “scientists have learned the tiny fish also have an appetite for the tadpoles of frogs, toads and other amphibians — including the threatened red-legged frog and the endangered Santa Cruz long-toed salamander.”

Up until a couple of years ago they were also dumping these voracious little fish into natural ponds, creeks and marshes for mosquito control. But the mosquitofish is not native to California and cannot be released into the wild without a permit. (Tell that to the fish.)

But they’re still getting out into the wild. Sometimes released by citizens, and sometimes on their own. According to the Mercury News story, they are hardy enough to endure being flushed and can even survive sewage treatment.

How do you say, “Law of Unforseen Consequences?” This is what always seems to happen when we try to control the world around us. /Gary

Read the complete Mercury News story here:

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No Responses to “Mosquitofish vs. West Nile: Good idea gone bad?”

  1. Gayle Reece Says:

    I have these in my koi pond along with some red eared slider turtles and two bullfrogs. Is this a bad thing? They seem so tiny. Will they eat the bullfrog’s eggs or injure the other fish? Who knew! It all seems so peaceful out there.

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