— When fly-fishing for wild brook trout, there are times that even the most perfect presentation is ignored.

Times when false casts are rhythmically pure, when the leader and tippet unfurl in a harmonious loop and the weightless offering of thread and feather and hook lands so delicately on the gin-clear water that nary a ripple is detectable.

Just like a mosquito would land, or some other aquatic insect for that matter. Something real and full of life sustaining nutrients.

Then, within seconds the rushing current sweeps the fly from the bucket-sized pool and another cast must be made. Perhaps closer to the bank, maybe nearer the waterfall. There are more casts, none as peerless as the first, and they too are met with rejection.

It can be frustrating, to say the least. Though it makes for a greater reward when a ravenous fish is fooled into thinking an impulsive dash from under sandstone cover to the surface is for its best meal in hours, perhaps days.

Greater still when the fish’s natural instinct switches from sustenance to survival and its frenzied runs erupt from the water in flashes of muted olives, yellows and oranges as it attempts to dispatch the hook stinging the corner of its mouth.

And greatest when, moments later, the fish is brought to hand and admired. Its length of six inches above-average, the mottled camouflage fingerprint along its back unique, the red and yellow and purple dots on its sides brilliant.

The fish provides a final, lasting memory as it’s carefully returned to the water, the source of its lifeblood - a source that is becoming increasingly endangered.

A hardened yet extremely sensitive species, brook trout are the only fish native to Pennsylvania. For more than a century their habitat of cold water streams, rivers, lakes, ponds and estuaries has been under attack by human progress.

From northern Georgia to the northeastern provinces of Canada, perhaps no other fish serves as a greater indicator of water quality. Brook trout are among the most intolerant of pollution and non-native species.

They have withstood the threat posed by the introduction of brown and rainbow trout. They have adapted to habitat degradation from acid mine drainage and outdated agricultural practices, along with stream fragmenting from dams and road culverts. As a result, brook trout have been greatly reduced or completely eliminated across more than 70 percent of their traditional Pennsylvania range, according to Trout Unlimited figures.

Now the state fish faces perhaps its greatest threat from what could amount to the 21st century’s own gold rush - in the form of natural gas found deep below Pennsylvania in the Marcellus Shale deposit.

The Department of Environmental Protection has distributed permits to drill some 3,000 wells so far. Those permits bring the rumor of an estimated 20,000 new jobs over the next decade. Those jobs would no doubt benefit the small communities across the northern tier counties, ones that have been among the hardest hit by unemployment.

That also happens to be where most brook trout are found - tiny mountain streams that tend to be isolated from humans. Often, the trout are confined to the uppermost headwaters of coldwater streams because pollution and poor water inhibits their ability to migrate. And for all of the economical benefits to drilling for natural gas, the increased likelihood of deteriorating water quality is very troubling.

Drilling into the Marcellus deposit is done horizontally by hydraulic fracturing, a method that is cost effective and efficient because it allows the tapping of multiple wells from a single spot by going down and sideways at various angles. A mix of water, sand and chemical additives is then pumped in at high pressure, cracking the shale and driving gas to the surface.

The drilling process uses three- to five-million gallons of water per well, which is usually drawn from the nearest water source. While some companies are committed to recycling the used water, wastewater disposal is neither consistent nor currently regulated in Pennsylvania. It wouldn’t be out of the question for a wild trout stream to be sucked dry or even supplemented by contaminated water with high levels of methane, arsenic, aluminum and iron.

In the grand scheme, brook trout aren’t the only ones in danger. What will come of the red-spotted newt? Or the American toad? Or any of the thousands of species that rely on cold, clean Appalachian mountain water to sustain their existence?

Some eastern states with large Marcellus deposits, like New York, have put moratoriums on drilling until studies can be done on the impact drilling has on water quality and other environmental consequences. Only recently have legislators in Pennsylvania scrambled to put regulations in place that limit the amount of toxic chemicals that can be released into the state’s waterways.

The regulations come on the heels of a pair of high-profile accidents at Marcellus drilling sites. The first was a well blowout in Clearfield County, on the border of Moshannon State Forest, that reportedly burned for 16 hours and sent natural gas and toxic wastewater spewing into the air. Another well blowout, in West Virginia’s northern panhandle, reportedly destroyed a drilling rig, sent flames shooting 50 feet high for four days and burned seven workers.

These blowouts show that drilling for the bounty of natural gas intertwines human and native creature with one dangerous - and profitable - business. They also show that brook trout in Pennsylvania face a much greater threat than a solitary fisherman who finds himself trying for the perfect cast to the perfect pool on his favorite mountain stream.

Brad Isles is a former editor of Allied News and writes an occasional outdoor column for the newspaper.