READING (AP) - By the mid-1800s, much of Berks County's forests had been cleared to build houses, heat buildings and make way for farms.
But as man prospered, trout did not.
Today marks the first day of trout fishing season, when anglers will flock to area waterways in hopes of hooking a slew of fish.
The majority of these streams and lakes have been stocked by the Pennsylvania Fish and Boat Commission. If they weren't, there would be little for sportsmen to catch.
Polluted and warm waters long ago depleted wild trout populations in Berks, leaving comparatively few local streams that can sustain them.
A resurgence of trout would mean cleaner, healthier water, biologists say, and would provide a much less expensive way to bolster the economic benefits of trout fishing.
But it would take investment in the environment by all stakeholders to turn the tide.
"This isn't rocket science," said Bernard Sweeney, director of the Stroud Water Research Center in Avondale, Chester County, who specializes in stream ecology. "In order to restore a watershed, you have to change the behavior of people living in it."
Warming waters a trout's enemy
Trout need cool, clean water to survive.
So the less shaded a stream is, the less likely it is that the fish can thrive there, said Mike Kaufmann, area fisheries manager of the Southeast Region of the Pennsylvania Fish and Boat Commission.
"Streams are substantially warmer than they were 500 years ago, when it was Penn's Woods," he added. "They rarely got above 75 degrees Fahrenheit."
There are two main factors that contribute to the warming waters: global climate change and lack of shade, Sweeney said.
And the more developed an area is, the more likely it is that nearby waterways are trout-free.
"If all of the trout have moved out," he said, "that's a signal that there's something wrong with the water."
The ideal habitat for trout, Kaufmann explained, has little or no sediment resting at the bottom of the stream.
Sediment, the leading source of water quality degradation in the U.S., is mostly made up of soil particles from agriculture, road construction, timber harvesting and residential and commercial development.
It's also a key contributor in the disappearance of wild trout populations.
Trout lay their eggs on beds of gravel. Water percolates through the tiny pebbles, keeping the eggs oxygenated. But if sediment blocks the water, Kaufmann said, the unborn fish suffocate.
A recent survey by the Fish and Boat Commission showed that most Pennsylvania fishermen weren't concerned by the lack of wild trout. Among 1,500 anglers surveyed, only 1 percent fish solely for wild trout, and the rest catch stocked fish.
"We know that many anglers don't even recognize that they exist," Kaufmann said of wild trout.
The commission raised 3.2 million trout in its state hatcheries for the 2014 season.
Todd Tanner, Montana-based writer and founder of Conservation Hawks, a nonprofit that educates hunters and anglers on climate change, is a trout fisherman himself.
If people truly love to fish for trout, he said, they need to pay attention to climate change and human habits that are a threat to natural reproduction of the scaled creatures.
"If we aren't careful, these streams won't hold any game fish," he said. "Even stocked fish."