Early last spring, perhaps it was late winter, I heard some interesting and exciting news through the ever-active fishing grapevine. At that time, fellow anglers reported that some catches of seriously large rainbow trout were being made from tributaries of the Pepacton Reservoir. We’re talking five-to-six-pound trout here. 

Sometime ago, I wrote about the evolution of that fishery, indicating that about 10 years ago, we started to see some decent-sized rainbows where the East Branch of the Delaware River entered the Pepcton Reservoir. Then a few years ago, we began to catch rainbows well upstream, in the vicinity of Margaretville. Based on my research, it’s apparent that the Pepacton population is the offspring of hatchery rainbows planted in Millbrook by the Tuscarora Club, which has been stocking that waterway with brook, brown and rainbow trout for many years. Despite the history of those stockings, it took a very long time for rainbows to migrate out of Millbrook and establish a viable population in the Pepacton and now its tributaries. 

What’s very interesting about this population of rainbows is the size they are attaining. Historically, rainbows in the Catskill region, which includes the Delaware River and the Ashokan/Esopus system, seldom exceeded 20 inches in length. That’s because those fish fed primarily on insects and, in the Ashokan Reservoir, on zooplankton. As a result, they never reached the size of the species living in the Finger Lakes and Great Lakes, where rainbows feed on forage fish like sawbellies. Since sawbellies are the primary forage base found in the Pepacton, it’s obvious the rainbows now thriving in that reservoir have adjusted their feeding to take advantage of that abundant food source.

While the Pepacton rainbow fishery has been developing, we’ve observed significant changes in the rainbow population that inhabits the Ashokan Reservoir and Esopus Creek. For many years, going back to the species introduction in the Esopus during the late 1800s, rainbow trout seldom if ever grew larger than three pounds. Suddenly, in December of 2024, I received reports and photos of some very large lake-run rainbows being caught in the Esopus. The information indicated that those fish were in the five-to-six-pound range. 

Those trout had migrated into the Esopus from the Ashokan Reservoir, preparing to spawn in February and March. Like the Pepacton rainbows, and because of their large size, it appears that the Ashokan fish are also feeding on sawbellies, which is a significant change and a reason for the large increase in size. 

Very soon, provided the Catskills receive a decent amount of rainfall and the tributaries, which are very low, rise accordingly, large brown trout from every New York City DEP reservoir in the Catskills will be on the move to the spawning grounds. That means that anglers, including fly fishers, can now fish for these large trout, because the regulations have been relaxed to allow year-round—albeit no-kill—fishing from October through March. Brown trout up to and exceeding 10 pounds will be part of this annual spawning run. 

So with the development of the late winter-early spring spawning runs of large rainbows from the Pepacton and Ashokan reservoirs, along with the fall runs of brown trout from those two reservoirs and trout from Cannonsville, Rondout and Neversink reservoirs, anglers now have two seasons to fish for very large trout with the fly rod. 

As a fisheries biologist and fly fishing angler, I’ve been promoting fishing for lake run spawners for several years. And now that the DEC has opened these fisheries, anglers have a unique opportunity to take very large trout on the fly. Granted the weather can be nasty, and fishing will be difficult, but the possibility of hooking a trout of a lifetime exists for those anglers willing to brave the elements. 

Hopefully the flows improve, and the trout will begin to head upstream. 

Anglers who decide to take on this challenge will need stout tackle. Six- or 7-weight rods with seven-foot leaders tapered to 10-pound test line will be necessary to handle these large fish, should one be hooked. These fish are not leader shy. And large streamer flies in size 4, shown in the accompanying photo, are the lure of choice. 

Let’s hope for rain to get these trout on the move, so we can go fishing!