North & South Rivers Watershed Association

Electrofishing to Tag Third Herring Brook Fish

On September 12th, our ecologist Sara Grady joined Mass. Division of Fisheries and Wildlife Southeast District Fisheries Manager Steve Hurley and his team to electrofish for eastern brook trout and other fish species in the Third Herring Brook watershed. They were also joined by Geoffrey Day from the Sea Run Brook Trout Coalition (https://www.searunbrookie.org/). Electrofishing works by submerging a battery-powered electrode into the water that generates a current. This current temporarily stuns fish, allowing them to be scooped up with a net and transferred to a nearby bucket of water for measurement and tagging, after which they are released.

The fish are tagged by injecting a small (12mm) transponder under their skin. These transponders act like an EZPass, and can be detected by antennas that are being set up at the Mill Pond and Tack Factory dam removal sites and at River Street/Broadway. This way we can know the movement of these fish and also track their growth if the same fish is recaptured in another year.

Most of the eastern brook trout that were found and tagged were in cold water tributaries to the Third Herring Brook, where they find refuge during the summer. However, one trout was found in the mainstem of the brook, in the middle of the former Tack Factory pond area! As temperatures cool down, we hope to see more trout move into the mainstem and possibly out to the North River to become “salter” brook trout, which are able to live in the estuary. Hopefully our antennas get some hits and we will have some additional data to report next spring.

This project is funded by grants from the Massachusetts Environmental Trust (MET).
By purchasing any of the state’s three environmentally-themed specialty license plates, two of our rivers, the Third Herring Brook and the South River, will be receiving funding to help restore their health! MET funds 15 projects across the state that will restore aquatic habitat, rivers and watersheds, monitor water quality, protect endangered species and promote environmental stewardship.

To see more photos from the tagging, go to our Facebook page.

Click here to see a video of the tagging.

Click here to see the system that will track the fish.

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