A major Gallatin Valley irrigation artery flows near my house. Throughout the summer months I often see fish in the ditch, but such sightings are bittersweet because I know that the days are prematurely numbered for these fish. Come fall, as irrigation demand decreases, the headgate is closed and the water flowing through the ditch is reduced to a trickle. This situation leaves the fish in the ditch without enough water to survive the winter. I would venture to guess that thousands, perhaps tens of thousands of fish (not all of them trout), perish in this ditch alone every year.
Last week a friend and I spent a couple of hours netting fish that were trapped in the ditch near my home. The culvert below my driveway creates one of the few remaining deep pools on this stretch of the ditch, and a large number of fish had congregated here in recent weeks. In this pool alone, we managed to net over fifty fish and transport them safely back to the Gallatin River. The majority of the fish in this location were fingerling whitefish, but there were a few trout in the mix, including one surprisingly large brown.
After removing most of the fish in the portion of the ditch near my house, we drove a mile or so to the headgate. I had a hunch that some larger fish might have recently moved into this area in a futile attempt to escape their watery grave. Sure enough we netted and released several large browns just downstream of the headgate. A couple of these trout were sizable by Gallatin River standards, measuring more than 16 inches.
This wasn't a sanctioned event. I don't have water rights on the ditch, and ditches don't fall under Montana's stream access law. But I wasn't about to sit around and do nothing. I'm not advocating that you follow my lead and trespass on your local ditch in an effort to save a few fish. But you may find that your local TU chapter provides an opportunity to get involved. For example, my local chapter (Madison-Gallatin) is coordinating an upcoming event to relocate trout from an irrigation ditch near the Madison River. Fish mortality associated with irrigation ditches isn't a problem everywhere, but if it's an issue in your area, contact your local TU chapter to find out how you can help.
For additional reading on the topic, the current issue of TROUT magazine features an excellent article about TU volunteers in Wyoming working to rescue trout from irrigation ditches. You can read the full article online through TU's website.