What happens to fish when streams flood?
As I type this blog Wednesday, July 25, rain continues to fall in southcentral Pennsylvania. Most streams are several feet above flood stage. Bridges are breeched, roads are closed, and I’ve officially pumped out my basement three times since Monday morning.
The nearby Quitapahilla Creek — which had calm, clear and impressive 61-degree water when I fished the Keystone Select Trout section in Annville Saturday morning — is now a roaring monster. Brown, gurgling, and swallowing up everything in its path, the local creek isn’t seeing my stream thermometer or fly-rod anytime soon.
Which got me thinking: What the heck happens to the fish when streams flood?
Did I catch the last trout in the stream this year? (If so, the 23-inch rainbow was a good one, taken on a scud fly just as the rain began to fall). But honestly, how are fish supposed to make it through severe flooding like this? It’s opening sinkholes and moving houses off their foundations, for heaven’s sake.
One friend went so far as to joke, “Oh boy. The trout are in the Chesapeake by now,” after seeing a video of the Quittie I posted online this morning. That made me ponder my question even further. As I tinkered around the house, trying to keep things dry and secure, the question kept bugging me.
Finally, I broke down and did what any good outdoor writer should do in a time when the public is probably wondering the very same thing I’m wondering: I emailed some experts and asked.
Their answers, interestingly, offered some hope, and I share them with you here:
“Fish survive floods and even droughts by seeking refuge areas where conditions are suitable to survival,” Pennsylvania Fish & Boat Commission Fisheries Management Chief Kris Kuhn said. “During high water, fish move towards the banks to find seams, pockets and eddies that provide calmer water and lower velocities. They hold behind rock substrate and submerged woody debris to find current breaks.
“Fish can also rest right on the stream bed as friction created by water flowing fastest near the surface slows down near the stream bottom. Sometimes fish move into smaller tributaries during a flood and drop back when flows recede.
“A high water event may cause fish to move, but they don’t suddenly get washed downstream. Some may drop downstream and others may take the opportunity to move upstream against the current and use the high water as a dispersal mechanism.
“A long period of muddy or silt-laden water can irritate fish gills and make foraging more difficult. With every challenge in nature there is also opportunity.”
Trout Unlimited Mid-Atlantic Organizer Rob Shane echoed Kuhn’s sentiments that fish are more resilient in floodwaters than one might think.
“Floods typically do not have a high mortality rate for fish on their own,” Shane said. “During high water events, trout typically try to find slow water and cover. This is oftentimes found up on the banks, behind big boulders, the bottoms of deep holes, or tucked under woody debris and undercut banks.
“Hatchery trout may have a lesser likelihood of surviving these events due to a lack of genetic diversity and life history allowing them to have experienced these in their formative years. Our wild trout, however, will be just fine.
“Floods are natural events and actually fairly good for the river. They move sediment out of the system and replenish riparian zones — assuming that said river is in a natural or semi-natural state.”
So there you have it. While all of us with basements might be doomed during high-water stages, the fish surprisingly are not.
Perhaps, I’ll follow the advice of another “hilarious” friend and stock trout in my basement for an impromptu trout rodeo. That would indeed be more fun than pumping water, and it might kill some time until the streams return to normal again. Stay dry everyone.
Note: It’s come to my attention that I have now written 100 blogs for the Pennsylvania Outdoor News website. I’d like to thank my readers for following along as I share my love for the outdoors and for taking the time to read about my adventures. It’s an honor. Thank you.