June 23, 2014 Share

Net Effect of Catch & Release on Trout Fisheries

Originally Published on Dec 15, 2011 “From the Docks” NBC Sports

In August, I had the privilege of visiting Quebec’s Leaf River, unquestionably one of the world’s best brook trout destinations. An interesting thing happens on a trip like this…the abnormal quickly becomes the norm, and in this case, that meant catching numbers of 16- to 22-inch brook trout each day. Catch & release became the norm.

It was when I was flying home at the end of the trip that I began to truly appreciate what I had just experienced…especially after I realized that the biggest brook trout I’ve ever landed south of the Canadian border, a fish from New York, measured a little over 13 inches.

Today, catching brook trout over 12 inches is challenge in many waters, particularly in the east, simply because fishing pressure and natural predation reduce the number of fish that survive long enough to grow that large. And that’s true even on waters where anglers practice catch and release.

In a recent column for North American Fisherman magazine, Dr. Hal Schramm highlighted the results of a Maine study that evaluated the effects of hooking mortality and angling effort on brook trout populations in state waters.

For a fishery to hold numbers of 12-plus inch trout, a significant percentage of the population must age five years or more. Brook trout grow to near 8 inches by age 2, 10 inches by age 3 and 11 inches by age 4, so surviving capture or avoiding it altogether is key reaching age five.

The study found an average post-release mortality rate of 5 percent for brook trout caught on a single hook fly, while those caught on passively fished bait averaged died at a rate of 32 percent once released.

Even at 5 percent mortality, even moderate fishing pressure (two anglers fishing ½ mile of stream for 4 hours per week) can reduce the number of larger fish by 50 percent when compared to control waters with no fishing and only natural mortality.

That anglers can and do impact fisheries is not news, but when we understand more about the effects we do have, we can make informed decisions on the water.—Steve