When I was a fisheries biologist, actually conducting  stream surveys, it was not uncommon for members of the local sportsmen’s clubs to question some of our management policies and regulations. One of the questions I was confronted with the most had to do with the numbers and sizes of trout, or the lack thereof, in the streams we were managing. 

Often, especially late in the season, anglers would say that they were not seeing the number of trout that they had in past years. That proclamation was mostly predicated on observations when the fishing was coming to a close, the hatches mostly over and the rivers low, in late-summer condition. 

So late summer was the time of year we conducted our annual electrofishing surveys. Over the years, we found that electrofishing was the best method to monitor the health and abundance of trout populations in small- to medium-size streams. Without exception, those surveys were attended by members of those sportsmen’s clubs, who not only observed our work, but helped lug our equipment all along the riverbank. 

When we surveyed the Amawalk outlet in northern Westchester County, members of the Croton Watershed chapter of Trout Unlimited would invariably join us.  This was mostly because there was always a lot of controversy about the regulations that we as fisheries biologists implemented on that stream, which was managed with size, lure and bag restrictions.

Before our surveys, members of TU  expressed doubt about the number and size of trout in the Amawalk. In other words, there was skepticism about the management policies we imposed to protect and support a viable fishery.

All these years later, I can write without reservation that the number of trout we collected, in 3,000 feet of electrofishing at the Amawalk, would astound even the most jaded angler/observer. 

Historical sampling data for that river revealed that we collected between 670 and 740 brown trout, ranging in size from two inches and 16 inches. The largest number fell in the six-inch-to-12-inch range. 

Keep in mind that the Amawalk is a small, infertile stream, with limited food supply and an average flow of less than 30 cubic feet per second. 

Unfortunately, electrofishing does not work as well on large rivers like the East Branch of the Delaware River. Because of their size, with large deep pools, rivers like the East Branch are electrofished with a boat shocker. Since most Catskill rivers generally have a neutral pH (pH is a measure of acidity), conductivity of the electrical current through the water is limited. As a result, the electrical fields are small and the trout flee as soon as they feel the slightest tingle. As a consequence, it is impossible to make an accurate population estimate in large rivers by electrofishing, using a boat-mounted shocking device. 

That is why it is difficult to refute anglers’ claims of low trout populations in some rivers, especially as the season winds down. Nevertheless, anglers need to keep in mind that as summer wanes and fall approaches, trout populations have been fished over for five months or more, been exposed to predation from mergansers, eagles, ospreys, and along some rivers, otters. Hooking mortality of released trout along with fish legally taken by anglers also has impacts on trout populations.Then, of course, there is the loss of young-of-year trout, associated with spring and fall floods that destroy eggs and newly hatched fry.

It is at the time of year, late summer and early fall, that trout are most vulnerable and most likely on the move, with some beginning an early migration toward their spawning ground. 

While brown and brook trout do not spawn until October and November, it is not uncommon for some pre-spawn trout, especially browns, to enter tributaries much earlier. I can attest to that with some degree of veracity, because on an August afternoon about 10 years ago, I hooked and landed a very large female brown trout while fishing in the East Branch of the Delaware, above the Pepacton Reservoir. After examination, there was no question that the fish was a reservoir trout, an early spawner on her way to a distant tributary. 

On that day I had been casting a small rapala, hoping for a few smallmouth bass for dinner.

So as the season progresses toward its end, and flows and fly-hatches decrease dramatically, rising trout becomes more and more of a challenge. Consequently, I believe it is normal for anglers to draw the conclusion that there are fewer trout in their favorite rivers. That may be true up to a point, taking into account all the factors that impact trout populations. But based on our surveys of the Amawalk outlet over a period of many years, I have found that there are always more trout in our rivers than we are aware of, and may wish to believe. Is that because we just can’t catch them as easily as we did in May and June?