August-September 2024 • Nebraskaland 51
of making the jump and continuing upstream. For most,
however, it is the end of the road. Even when water levels
rise to the level of the culvert during heavy rains, stream
velocities can be too swift for small fi sh to navigate.
While some fi sh spend their entire lives in one section of
stream, others need to move to reach spawning or feeding
areas. "Most of our minnow species have an innate pull to go
upstream, to the extent that they're able, to fi nd new habitat
or for spawning," said Cassidy Wessel, a Game and Parks
wildlife biologist in northeastern Nebraska.
Some are pelagic spawners, releasing their eggs to drift
downstream. If those eggs drift through a perched culvert
and the young are not able to make it back upstream, it can
aff ect the overall population.
Fragmentation is one of several reasons nine of the 30
native fi sh found in cool-water streams in Nebraska are listed
as endangered, threatened or at risk.
Fish Need a Ladder
The impetus for the study came a decade ago, when Wessel
led a survey of at-risk species, such as the northern redbelly
dace, on three streams from their headwaters to their
confl uence with the Keya Paha River.
"We just ran into a lot of potential barriers," Wessel said.
And there are more barriers today following historic
fl ooding in the spring of 2019, and another round of localized
fl ooding on Long Pine Creek and others in the fall of that year.
"Those fl oods just accelerated what was happening slowly in
a lot of streams," Wessel said. "We were looking around and
thinking, 'My gosh. Is there any way we can help?'"
Fisheries biologists Kali Boroughs and Hunter Swanson use electrofishing equipment to sample minnows in Willow Creek
below a culvert fitted with a fish ladder in Rock County.
