The Deerfield River Trout Spawning Study, Part 1

The Deerfield River Watershed Trout Unlimited Chapter (DRWTU) recently conducted a scientific and volunteer-based survey that found spawning brown trout in the main stem of the upper Deerfield River.

This means that there could indeed be wild brown trout in the river.  This invaluable resource is being taken for granted by some, but others are doing what they can to ensure a healthy river habitat that supports the Deerfield River ecosystem and the multiple tourism-based businesses that rely on this magnificent river.

Learn more about it in this three-part series.

You may have heard that the Deerfield River has been called the “hardest working river in the East.” It’s not hard to imagine that when, within its 73 miles of water, there are 10 different hydro-electric dams operated by three different companies.

The section that is most pertinent to many anglers is the prime C&R fishing area below Fife Brook Dam.  The 10-megawatt Fife Brook Dam, and its 600-megawatt pump storage companion Bear Swamp, is owned by Brookfield Power Co., which is currently in the midst of its federal license renewal process to continue producing electricity from the Deerfield River, a public resource.

The Federal Energy Regulatory Commission (FERC) denied requests from MassWildlife for Brookfield Power to conduct spawning and other studies to look at the impact of its hydro-peaking operation on the trout in this 17-milesection of the Deerfield.

FERC denied these requests because there was no proven negative impacts by Fife Dam’s operations.

As of the fall of  2017, no group or agency had verified the claims made by anglers and guides that trout were spawning in this section below Fife Brook Dam.  Although many anglers had been known to catch brown trout that were quite a bit smaller than those stocked by the state, most people believed that the spawning was taking place in several of the river’s upstream tributaries.

However, members of DRWTU thought differently.  Given that FERC wasn’t going to order Brookfield to do a study, DRWTU decided to conduct the first study on the Deerfield to find out if salmonids actually were spawning in the main stem.

And, they went out and got help. Beyond DRWTU volunteers, support came from other TU chapters and the MA-RI TU Council. Donations from individuals and local businesses, such as the Deerfield Fly Shop and Thomas and Thomas Rods.

Volunteers help with the redd survey.

Hydro-peaking can affect entire river ecosystems, scouring away riverbanks, substrate and biomass. What that means is that, in some rivers, there is a breakdown of invertebrates available as forage by as much as 90% within a few km of the dam (Moog 1993).

Beyond that, DRWTU members were concerned that daily fluctuations in river flows caused by hydro-peaking were affect the ability of eggs to survive. With variations in flow that can vary by more than 1000 cfs, they thought that trout were building redds at high flows and then these were being dewatered during low-flow periods.

Although eggs in redds are surprisingly resilient, surviving in moisture levels as low as four percent in the surrounding substrate (Reiser and White 1983), these de-watered eggs are susceptible to freezing, and frigid conditions can cause egg survival to be less than one percent (Reiser and Wesche 1979).

Example of a dewatered tailspin in a salmonid redd on the Deerfield River. Photo courtesy of Mike Vito of DRWTU

Surveying the 7.5 stretch below Fife Brook Dam, the volunteers found about 100 redds! Upon further investigation, only 37 contained eggs.

Kevin Parsons, the current DRWTU President, is concerned by the low percentage and believes there are more questions raised than answered about the impact of the hydro-peaking on wild trout spawning. Twelve of 25 redds found in shallow water were de-watered at the minimum flow of 125 cfs.  Of these, eight contained eggs.

Eggs from 33 different redds were collected following protocols developed by Dr. Michael Cole, PhD, a member of DRWTU, in conjunction with biologists from MassWildlife, the United States Fish & Wildlife Service and Don Pugh, a retired biologist from the US Geological Survey.

A pink precious pearl of egg among the rough

The collected eggs were sent to the National Genomics Center in Montana run by the US Forest Service.  Using genetic analysis, the scientists at the National Genomics Center determined that of the DNA from viable eggs, 23 were a 100% match to brown trout and two were 100% matches to rainbow trout.

And just like that, the DRWTU conclusively demonstrated that fish were trying to reproduce in the main stem of the Deerfield.  Now they wanted to see how the eggs survived the winter and frequent de-watering at low flows.

Stay tuned for Part 2.


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9 thoughts on “The Deerfield River Trout Spawning Study, Part 1

    1. Thanks Ciro, I think the parties involved are hoping to get the dam to operate in a way that creates minimal impact to energy production, creates better conditions for the river and it’s inhabitants, and makes sure that local businesses that rely on the river to all come out on top. Fingers crossed that can happen!

  1. Nice job on this, Joe! We’re actually starting to plan a second and more elaborate spawning study this fall. We’re going to need a LOT of volunteers! Anyone interested should get in touch with me. A great learning experience that I feel can make us all better anglers. Best way to reach me is to leave a message on our Deerfield River TU Facebook page. I will definitely get back to folks promptly! Tight lines mon ami!!

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