Video: Tagging Along with Sea-Run Brook Trout
February 28, 2012
Sea-run brook trout, also known as “salters”, are beautiful and fascinating fish. Although they are believed to be genetically identical to landlocked brook trout, salters spend the winter in saltwater and return to their natal freshwater rivers and streams during the warmer months. Many New England coastal rivers once hosted robust runs of salters, until widespread damming, pollution, and riparian agriculture destroyed their habitat. Now sea-run brookies, are rare, found only in a handful of streams and rivers.
One such stronghold is Red Brook, located in the towns of Wareham, Plymouth and Bourne in Southeastern New England. The narrow waterway flows for 4 miles through the heart of the Theodore Lyman Reserve, which is managed jointly by The Trustees of the Reservations and Trout Unlimited. Over the years, the brook and its native fish have endured their share of threats, most notably from dams created to form bogs for cranberry growers upstream. The bogs have limited water flow, raised water temperatures and caused nutrient loading due to the use of fertilizers.
Yet the salters of Red Brook have somehow endured, and now a team of biologists and concerned fishermen are going to great lengths to study—and ultimately protect—these unique fish.
In June 2011, I joined members of the Massachusetts Division of Fisheries and Wildlife (MA-DFW), the U.S. Geological Survey, Trout Unlimited, and the Sea-Run Brook Trout Coalition as they conducted a 2-day collecting and tagging study in Red Brook designed to shed more light on this mysterious species.
On a humid day that had thunder rumbling in the distance, DFW Southeast District Fisheries Manager Steve Hurley and his assistants waded the river with an electrode, stunning the fish so they could be scooped up with nets and placed in coolers. The fish were then whisked to a waiting SUV staffed by members of the U.S. Geological Survey, who weighed and measured the trout, took scale samples and placed acoustic tags inside the fish’s bodies. Smaller trout received 12 mm PIT tags, which indentify each trout and emit a signal that is picked up by sensors placed along the brook as a tagged trout swims past them.
Recaptured trout are also scanned with handheld sensors to see if they have already been tagged. Larger trout (Red Brook trout have been captured up to 15”) are surgically implanted with larger acoustic transmitters, which emit signals that are picked up by receivers placed both in the brook and in neighboring Buttermilk Bay. In the past 2 years, the receivers have revealed that some salters range as far as the Massachusetts Maritime Academy, over 2 miles from the mouth of Red Brook!
One trout (dubbed “the devil fish” because its acoustic tag code is 666) was tagged on June 8, 2010, when it measured about 11”. The same fish was recaptured on June 1, 2011, having grown about 3”, and most recently on September 20, 2011. “This fish is true salter,” said Hurley, “as it was last detected in the west side of Buttermilk bay on January 23, 2011.”
The biologists hope to use the tagging data to learn more about the size, makeup and survival rate of the Red Brook salter population, as well as how fast and big the fish grow, where and when they spawn, and how far they roam. This data will in turn be used to protect the fish and enhance the existing population, and could also be used to restore runs in other coastal rivers and streams where habitat has been improved.
Stay tuned to New England Boating to learn more as we present the findings of these ongoing studies.
By the way, the Theodore Lyman Reserve is open to the public and features trails that wind along the brook and down to the beach where it flows into Buttermilk Bay. Fly fishing is allowed, on a strictly catch-and-release basis, and the brook is a good place to launch a kayak to explore the lower portion of the river and the adjoining bay. For more information: http://www.thetrustees.org/places-to-visit/southeast-ma/lyman-reserve.html