(This video was originally broadcast on Iowa Outdoors, Episode 401, May 1, 2014.)

Just beyond the Plexiglas of the Botanical Gardens flows the Des Moines River, a popular spot for urban fishermen. 

River angling is heating up all across Iowa's waterways this time of year, but the data on fish migration for spawning and overall behavior is essential for keeping a healthy population for future generations.

In some eastern Iowa riverways, the DNR is monitoring the movements of a unique fish not often found in central Iowa, Shovelnose Sturgeon.

Nearly 150 different fish species inhabit the rivers and streams that ripple like veins throughout Iowa's countryside. In eastern Iowa, one so-called bottom feeder is drawing attention from the Iowa DNR's Fishery staff. And its movements are under investigation.

Scott Gritters, Fisheries Biologist, Iowa DNR: The tail is busted off and that's pretty common with sturgeon that we lose that tail. Very rugged fish. You can see we had one with the tail chopped off, you know, a fish that can live in strong current. You'd have to be rugged to live out where we're at. You see how the current is grabbing the boat and throwing us around. They live in it no problem. You can see their design with those scutes and their pectoral fins, they can sit right on the bottom, their mouth is straight down and basically vacuum cleaning out there in very rugged current that you and I couldn't hold in at all.

Shovelnose Sturgeon often drift along the main channel of large waterways, hovering at the bottom amongst sand and a swift current. These prehistoric looking fish don't often stay in the same spot for too long. 

Gene Jones, Fisheries Technician, Iowa DNR: This is how they feed on the bottom. They use these to locate food and they extend their mouth down, I always called it like a Hoover Vac.

They're active during their inconsistent spawning cycles and when they do begin a journey it can span hundreds of inland water miles over a few generations. Those travels, including how far and how quickly, are important data sets for fishery biologists.

Denny Weiss, Fisheries Technician, Iowa DNR: I grew up in Burlington back in the '70s when I was in high school, I used to commercial fish out in the Mississippi. We would drift trammel nets for sturgeon for the small fish market. This net goes down at the bottom, it's about six to eight foot tall or deep but once that current pushes it, it's probably three or four foot off the bottom just rolling right along the bottom. The fish are going to get all caught up in that web.

Equipped with a vacuum sucking mouth, Shovelnose Sturgeon mainly devour aquatic insect larvae. They venture from feeding grounds downstream to spawning grounds upstream. Female eggs laid in an Iowa waterway often hatch within five days and the surviving larvae float downstream into suitable rearing zones protected from aquatic predators.

Scott Gritters: On the female we can see how many times she was potentially pregnant coming up here. As I was explaining earlier, they don't spawn every year. They maybe spawn every other year or every third year. And so hopefully through this data set we can see how often they're coming up here and spawning.

Gene Jones, Fisheries Technician, Iowa DNR: This is a girl. Look at the belly, you can see how dark that stripe is, full length. If you hold it, it protrudes below mid-line. See that, see how the belly really droops down?

Shovelnose is the smallest and most abundant species of freshwater sturgeon found in the U.S. and the only kind commercially fished in the entire country. And they grow slowly. They aren't known for becoming massive species inside Iowa's rivers and streams. According to the Iowa DNR, the state record for a captured Shovelnose Sturgeon is only 12 pounds.

Scott Gritters: Well, you know, we're trying to learn a lot about this unique species. This isn't a fish that is fished heavily but it is fished some. And there's certainly a demand on this species. 23 or 24 species of sturgeon in the world and every other species except for this one is overfished.

Known for moving up and down the Missouri and Mississippi water systems, Shovelnose are increasingly creeping into Iowa's inland tributaries. And their presence could have an unwanted, and perhaps unexpected, impact on the ecosystem. 

Scott Gritters: I study here, we can really compare that to the Mississippi. And, again, some of these fish might actually end up in the Mississippi anyway and be caught commercially by anglers.

Scott Gritters: When people come across our fish, you see where we're putting the tag in the pec fin and if they come across one of those tags there's several things we'd like the anglers to do. First, get the number of that tag, try to write it down. You see our numbers are five digits, it can be hard to remember, so if you can write it down right away that'd be awesome. If they come across any of our tagged fish, sometimes we have tagged northerns, tagged walleyes, we always want to know what that number is and where did they get that fish. And then, if they can, we'd like to get a length on it.

It's just another reason the Iowa DNR is tracking their movements and keeping tabs on fish some would consider a simple bottom feeder.

Gilchrist Foundation