Fish are always on the move -- to find food, mates, safety, etc. -- and running into barriers can be more than simply inconvenient. Delays in their travel can result in not eating, freezing, overheating, or missing their shot at spawning.
It quickly becomes a matter of survival for many species.
What's Making Travel Dangerous for Fish?
Unremarkable and invisible to most of us, round culverts (big metal pipes that carry streams through roads when there’s no bridge) are common barriers.
We drive over culverts every day without even knowing. There are literally hundreds of thousands of culverts across the United States, and the majority are causing problems for fish.
Traditional round culverts are not designed with fish or the stream’s natural behavior in mind.
First, they’re almost always too small. This results in a more concentrated flow, like a firehose, which makes it difficult or impossible for fish to swim through.
A second problem is that many culverts are placed above the stream grade. When there’s a height difference between the stream and the bottom of the culvert it’s referred to as “perched” or “hung” [above the stream bed] and fish can't jump up into it or continue their journey.
It’s like being locked out of your house. For us, it's an inconvenience. For fish, it's survival. There is no detour or alternate route. Fish don't have other options when their pathway is blocked.
Third, wood, rocks, and sand moving downstream get backed up. This deprives the downstream of habitat for fish (fisherman may know that the best places to find a fish in a stream is behind a boulder or hiding under a log). Sometimes, a reservoir forms upstream, which can kill critical shade trees around the stream. As a result, temperatures increase and invasive species that thrive in lake-like conditions prosper.
Flop-free Journeys for Fish
The good news is that we have a dedicated team working on this prominent issue -- the National Fish Passage Program. There are fish passage engineers, hydrologists, fisheries biologists and other specialists across the country, working to keep fish and streams/rivers moving along safely.
A primary goal is to restore fish passage where man made roads and dams cross streams. The team invests federal fish passage dollars -- and time -- into collaborative partnerships and on-the-ground projects. Some projects are too large and complex for any one partner to undertake alone.
An example of a partnership to replace a 5 foot round culvert with a fish-friendly 14 foot arch culvert. Photo by Katrina Mueller, USFWS.
Examples of projects:
- Replacing a traditional too-small round culvert with a much larger arch or box culvert that’s sized to fit the stream’s width, accommodate high flows, and provide a natural bottom through the crossing that young/adult fish and weak/strong swimmers can all navigate.
- Removing a dam.
- Making sure agricultural irrigation systems don’t divert fish out of streams and into fields.
Good crossings keep people moving along safely, too! These projects not only benefit fish and boost fishing opportunities but improve infrastructure, reduce maintenance and safety concerns, perform better in floods, and keep streams in their natural functioning state.
Don't Let Fish Flop
These project and partnerships are a great start, but we need you, too. Here's a few ways you can be a part of the solution:
- Learn about the fish in your local creeks and rivers. We have a lot of cool fish, from colorful darters to salmon and giant sturgeon. Fishing, snorkeling, and underwater photography are a few ideas to explore.
- Be a voice for fish. Share this message with as many people as you can and help build awareness about the need for fish-friendly roads.
- Get to know your local Fish Passage Program coordinators. They are great sources of technical expertise and have some limited funding available for priority fish passage projects. Some regions even offer fish passage workshops for planners, engineers, and construction firms.
- Join and support your local Fish Habitat Partnership.
- Find out if your local or state governments have fish-friendly road policies.
Together, we can make sure fish travel safely and don't flop!
Female pink (humpy) salmon moving through a new, larger culvert with a natural streambed in Cordova, Alaska. Photo by Katrina Mueller, USFWS.