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Invasive Species Alert!

Hey kids, have you seen this alien invader?

Two exotic freshwater species, the Asian clam and the zebra mussel, have invaded Missouri’s waters. The Asian clam arrived in the western United States in the 1930s. By 1968, it had spread throughout Missouri and is most abundant in streams south of the Missouri River. They are usually found in rivers, ponds and lakes on banks and gravel bars.

In the mid-1980s, zebra mussels hitched a ride in the ballast waters of freighter ships traveling from Asia to the Great Lakes. Now these tiny mussels can be found in the Mississippi and lower Meramec rivers in Missouri. This summer, they were discovered in the Lake of the Ozarks.

Exotics harm native species

• Asian clam and zebra mussels can reproduce much faster than native mussels. They don’t need a fish host to carry their larvae as native mussels do. In fact, one zebra mussel can produce more than a million larvae a year.
• Zebra mussels can attach to any solid surface, including other mussels. If enough attach to a native mussel, it cannot open its shell and soon dies. See photo on left side of page.
• Scientists believe Asian clams compete with native mussels for food and habitat.

Stop the spread of invasive mussels

• Do not move bait or water from one stream or lake to another.
• Check all surfaces of your boat and trailer for zebra mussels. Destroy these dangerous hitchhikers before putting your boat in other streams or lakes. Go to www.mdc.mo.gov/nathis/exotic/zebra for cleaning tips.

Dear Professor Nutkins:

I was reading page 14 of the August issue and made the observation that on the top it talks about insects in general, but on the bottom talks about spiders with no regard to scorpions or any other arachnids, and I think it should have said arachnids, instead of spiders.

Mike, age 12

The top part of the page identified parts of an insect. The bottom part of the page identified parts of a spider. But you are correct, spiders are arachnids. Other examples of arachnids that live in Missouri are scorpions, ticks and mites.