Traveling the American Interstate River System
BY COLBY WRASSE, COLUMBIA FWCO
on open river systems. Credit: Colby Wrasse, USFWS
The interstate highway system in the United States is a vital conduit for nationwide commerce and travel. Linking the East Coast to the West Coast and most points in between, interstates allow for relatively quick and easy travel between states. Similarly, the Missouri River/lower Mississippi River system functions much like an aquatic highway linking the Rocky Mountains to the Gulf of Mexico. It is this American Interstate River System that allows fish and other aquatic organisms’ quick passage across state borders. Some recent fish catches made by Columbia Fish and Wildlife Conservation Office (FWCO) on the Missouri River reminded us once again how interconnected our waterways are.
Last fall, we recaptured a shovelnose sturgeon initially tagged in the state of Mississippi. This particular sturgeon was recaptured more than 700 river miles from the initial capture site, having travelled through portions of at least six states. This marked the second shovelnose sturgeon we have recaptured that was originally tagged in the Magnolia State. Although 700 miles is a long way to swim, it pales in comparison to the long distance journey made by the American eel.
Born in the Sargasso Sea, in the Atlantic Ocean, the female American eel enters fresh water to live for several years, before returning to the ocean to spawn. Given the great distances from the Sargasso Sea to Missouri, we were pleasantly surprised to have captured two American eels this spring. Over the past decade, we have captured more than a dozen American eels that have traveled thousands of miles through oceans and rivers as part of their interesting and complex lifecycle.
However, there are obstacles on the Interstate River System. Dams on rivers can act like speed bumps, or all out road blocks. Diversion of water for human purposes can slow fish traffic to a crawl. Whatever happens on one part of the Interstate River System ultimately affects all travelers. While native migratory species, like sturgeon and eel, benefit from travel on the open rivers, so do unwanted travelers, such as invasive carps. Understanding the complexities inherent in a large, open river system is challenging. The interconnectedness of our waterways necessitates the flow of vital information among scientists and resource managers. Like those engineers who developed the Interstate Highway System, we must also work at a landscape scale.
This is part of what we do at Columbia FWCO. As part of Pallid Sturgeon Population Assessment, we work with partners in Region 3, Region 6 and several state agencies to monitor fish populations along the 2,300 mile long Missouri River. Hopefully through these types of collaborative, landscape scale efforts, fish like the pallid sturgeon will continue to travel the American Interstate River System for millions of years to come.