Correcting a recent goof and getting schooled about trout diets
First, a word about a goof.
A couple of weeks ago, an article I wrote for this page described the Division of Natural Resources' 1966 stocking of Erie-strain walleye in Summersville Lake as a "goof."
That might have been accurate, but it wasn't at all fair.
Stocking Erie-strain walleyes in West Virginia waters was a widely accepted practice in 1966 when the lake was impounded. Biologists back then didn't have the advanced knowledge of genetics they have now.
They couldn't have known that fish from New York's Lake Chautauqua or Pennsylvania's Pymatuning Lake wouldn't thrive in West Virginia waters as well as the Gauley River walleyes already present in Summersville.
At the time, a walleye was a walleye was a walleye. Not until the year 2000 did scientists realize that walleyes found in West Virginia's New, Gauley and Elk rivers were genetically different and far better adapted to thrive in the Mountain State's relatively infertile waters than walleyes from other locales.
What DNR officials did in 1966 was a goof only through the rather narrow lens of 20/20 hindsight.
In other words, I goofed by calling it a goof.
Call me a masochist, but I actually enjoy sitting through biologists' presentations about things scientific.
At the recent Northeastern Association of Fish and Wildlife Agencies conference in Charleston, I got to sit in on several. One that really piqued my interest was a West Virginia University study on the dietary habits of young brook trout.
Using tiny syringe-like stomach pumps, researcher Jared Studinski removed the stomach contents from live 3- to 4-inch brook trout and returned the trout to the stream from whence they came.
The study purpose was to determine whether young brook trout ate better in heavily forested areas or in areas where the forest had been cleared.
If you'd asked me before I watched the presentation, I would have said brookies in the forest-covered part of the stream would have eaten much better.
I would have been wrong.
Studinski found that brookies in areas where the forest canopy had been removed consistently had fuller stomachs than their deep-forest brethren. The reason appears to be that aquatic insect populations undergo a bit of a boom when the stream gets exposed to sunlight.
In the forested areas, the little brookies relied heavily on terrestrial insects - ants, bees, beetles, etc. - for their food.
In the timbered areas, they relied more on aquatic insects in general and on small mayfly larvae in particular. Studinski said populations of one particular mayfly genus, the Baetids, tripled in areas where the canopy had been cut away. Trout, being opportunistic feeders, were quite happy to chow down on the sudden bonanza.
Studinski's study will definitely affect my approach toward fly-fishing small brook-trout waters. From now on I'll focus on terrestrial flies when I'm fishing heavily canopied streams, and on mayfly nymphs size 18 and smaller when I'm fishing streams where loggers have opened the canopy.
Better fishing - one of the hidden benefits of being a diehard science geek.
Reach John McCoy at email@example.com or 304-348-1231.