Adopt-A-Fish update – April 3, 2008
and doing just fine
By DAVE FULLER
Montana Fish, Wildlife and Parks
FORT PECK – The fisheries researchers are not the only ones coming back to the Missouri-Yellowstone Adopt-A-Fish Program in 2008. Count Spathuala, the Plantonater, or Mr. No Bill - depending on which school's name you prefer - has returned to the program once again as well.
We don't discriminate against the fish or that are up for adoption, even if they don't have all their parts. Take this paddlefish for example.
We used this same fish back in 2005. What a mover! This paddlefish, even without it's paddle, moved over 700 miles that year. It over-wintered in the Missouri River near Wolf Point during 2004-2005. He migrationed up the Milk River above Glasgow twice, down the Missouri River to Williston, ND for the summer and then back up to Wolf Point - right back where it started that year.
This fish demonstrated what biologists call inter-annual site fidelity. This is when a fish spends different portions of the year in different rivers or different areas of a river.
This seems to be very common in our blue suckers, paddlefish and pallid sturgeon, to name a few species. This can be due to preferred spawning, feeding or over-wintering areas. If flows are good in the Milk River this year, I would expect a similar migration. This could also be where this paddlefish hatched from some 30+ years ago.
Natal-site fidelity is when a fish returns to the same river that it hatched in to spawn itself. It is well-known in salmon. Now, we are learning that other species of fish also prefer to spawn in the same area they were born.
So just what is that paddle for?
In the early 1900's, the paddle was originally thought by scientists to be a shovel used for digging up mud and silt as the fish searched for small organisms. But the paddle is not a shovel, a scoop or a spear. If you look closely at the paddle you will notice that it has no scratches on it. Besides, we know that paddlefish are mid-water filter feeders and are not feeding of the bottom.
We do know that the paddle and head are covered with thousands of tiny sensory pores capable of detecting minute electrical charges associated with zooplankton. The same sensory pores can detect objects in muddy water that can't be seen and may be able to detect differences in water velocity and temperature.
The paddle also appears to function as a vertical rudder, providing lift, allowing the fish to open its mouth wide for filter feeding with out being dragged to the bottom.
Weekly updates on our radio-implanted fish can be found on the Missouri-Yellowstone Adopt-A-Fish home page with updates posted Thursday mornings in April and May. Just click on the Find your Fish button on the home page. The program is sponsored by Montana Fish, Wildlife and Parks, The Billings Gazette, Walleyes Forever, Montana PikeMasters, U.S. Army Corps of Engineers, U.S. Geological Survey, Bureau of Reclamation and the U.S. Fish and Wildlife Service. The program is free.
School classrooms, youth fishing clubs and home schoolers can sign up for the program and adopt and name two fish. Just go to the Web site and click on the How To Adopt Button or send us an e-mail at Missouri-Yellowstone Adopt-A-Fish.
Adopt-A-Fish correspondents Dave Fuller, at Fort Peck, and Matt Jaeger, at Glendive, are fisheries biologists with Montana Fish, Wildlife and Parks. They’ll post weekly updates every Thursday throughout April and May on this site and in the Outdoors section of The Billings Gazette.