• Canoeists paddle by tree lined shores

    Saint Croix

    National Scenic Riverway WI,MN

A Case of the Jumps

January 18, 2012 Posted by: Aquatic Biologist, Byron Karns

A dry witticism among my colleagues and friends on the St. Croix River used to involve zebra mussels providing fodder for my career until retirement many years in the future.The Riverway has been pursuing a prevention and control plan for these little critters since the early 1990's, and I have been involved with the Park Service's efforts outlined in the Plan almost as long (the Plan can be read online at http://www.nps.gov/sacn/naturescience/zebra-mussels.htm). Along with tending to the River's native freshwater mussels, insects, water quality and generally most things aquatic, I figured a challenging and rewarding career was assured.Little did I know my moxie was yet to be tested...

Big, invasive fish-the likes of which provide YouTube gold-are making their way into our neighborhood: Asian Carp. Their instinct to jump out of the water when disturbed has resulted in both amusement and trepidation. Working with folks from the DNR on strategies for prevention, I have been concerned about these animals since the mid-nineties.Yet we just couldn't seem to sound the alarm loud enough.

What a fish in hand can do!

This past April, a 27 pound Big-Head Carp (one of several species in this group) was caught in a commercial fishing net in Prescott. In August, results from water tests showed evidence of Silver Carp (another of the species) as far upstream as St. Croix Falls.This was big news and a big, big problem if Asian Carp ever become established here on the St. Croix National Scenic Riverway.

This Saturday, January 21st, I will highlight current understanding about Asian Carp biology and impacts, and what is being done to address this impending menace. Presentations will be at 10:00 AM and 1:00 PM at the St. Croix Visitor Center, located at 401 N. Hamilton Street in St. Croix Falls. For more information about these free presentations, or to arrange to attend, please call the Riverway Visitor Center at 715-483-2274.

Additional information on the current Asian Carp prevention plan can also be found at http://www.nps.gov/sacn/naturescience/upload/Asian-Carp-action-plan-11-2-2011-Final.pdf.


Dozens of large Silver Carp are seen jumping from the water in the wake of a motorboat on the Illinois River (Nerissa Michaels/Illinos River Biological Station)

exotics, fish, silver carp




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Did You Know?

A green dragonfly emerges from its old skin, seen below.

Dragonflies spend most of their life living in the water. Eventually they climb out of the water and grab onto something. Here they will emerge from their old skin like a butterfly emerges from its cocoon and fly away.