I subscribe to Trout Unlimited’s magazine along with other environmental groups I belong to. I often gain much information I utilize for this column out of these NGO’s publications, and occasionally get surprised by research that I didn’t yet know about.
So, when I found out investigations in the Umbagog region on brook trout showed they move into bigger bodies of water to overwinter, and at considerable distances, I read further.
Turns out a young female biologist conducted this research with Dartmouth and determined that tagged fish sometimes moved over 70 miles in a year and returned to their same spawning beds next season.
We commonly think of this beautiful trout as a native cold-water fish and find it in unspoiled headwaters, as it needs pure streams uncontaminated and with cold temperatures.
They will move uphill as far as they can. One could also say we have driven it there, ruining other stream courses with pollution and rising temperatures. For fly fishermen in NH and Maine, this is a common theme and worries them greatly. And we don’t like it breeding with hatchery stocked fish to dilute their genes either.
So, the streams that flow into Lake Umbagog are a purist’s dream and reflect our myths. All admit there are few vibrant places left like this and they are to be treasured. Therefore, her research was conducted there, and it could be said as a joke this much desired fish is neither our state’s or our neighbor’s, since it travels across state boundaries. The watershed has to be managed as a whole.
This area is owned by Dartmouth College and is known as the Second College Grant, or simply “the Grant.” The Dead Diamond River enters here from the north, and then flows 10 miles south to its confluence with the Swift Diamond River, which comes in from the west.
The larger Diamond roils through a deep gorge, and merges with the Magalloway River at the southeast corner.
Next, it all drains into 7,850-acre Umbagog Lake, which also is fed by the Rapid River from the east in Maine. This is a warmwater fishery, quite shallow despite its size and contains pickerel, panfish and pike, but also native Eastern brook trout that migrate here each winter from these rivers. 50 miles of interconnected waterways result.
In 2005, New Hampshire Fish and Game biologist Diane Timmons began a seven-year study using active radio tags on brook trout in these rivers. The information derived showed several surprises, starting with how much brook trout moved each year.
One particular fish swam a remarkable 75 miles from the Dead Diamond to the Magalloway River, then to Umbagog Lake and back up the system to the Dead Diamond to spawn. It also revealed that brook trout congregated in certain places during the winter in this weedy lake. Over the next several years, Timmons identified 35 spawning sites, which the tagged trout returned to each year.
When I observed parental fish in Channing Snyder’s ideal trout pond in Eaton during December, I could see them wriggling about and clearing silt from their favorite incoming cold groundwater seams. They took turns keeping their redds debris-free, needing that gravel clean. The females moved to chosen sites in late fall and kept working as the black ice soon covered the pond. I could stand there and watch them below.
The importance of radio tagging proved the interconnectivity of waterways in this New Hampshire state research for fisheries management. If there are no dams or impediments, brook trout can travel all over. Previously, it was thought they didn’t move much beyond five miles. It helps Dartmouth maintains this Grant for sustainability and the land has big boundaries.
The radio-tag project also overlapped with research by Dartmouth PhD candidate Keith Fritchie looking at groundwater and other thermal indicators of spawning beds. While we have thought brookies are small headwater specialists, we are now seeing small stream fish going to big habitats, and big habitat fish moving to small streams.
The Northeast — especially Maine — has multiple life histories of brook trout. Along with these river migrations observed, there are lake and pond populations and even sea-run brook trout along the coast. The total number of populations of this desired fish are unknown.
Trout Unlimited has done fishing surveys on more than 400 remote Maine ponds in search of brookies and participating volunteers pass their information along to the Maine Department of Inland Fisheries and Wildlife to enable the state to come back and complete formal surveys documenting wild brook trout.
These findings included some robust trout populations for improving habitat connectivity, even along the coast. Trout Unlimited says it is vital that we do not allow brook trout to be conceptually relegated to just small headwater streams and instead conserve their remarkable habitat diversity.
Dave Eastman also broadcasts “Country Ecology” four times weekly over WMWV 93.5 FM. As vice president of the Lakes Region Chapter/ASNH, he welcomes you to monthly programs at the Loon Center in Moultonborough. He is available at: email@example.com (or) countryecology.com for consultation.