The Third Herring Brook will be able to keep its “cool” with new protection provided from being designated a Cold Water Fishery Resource by the state of Massachusetts. Coldwater streams are areas or reaches of streams and small rivers with water cold enough throughout the year to support coldwater fish such as brook trout, slimy sculpin, blacknosed and longnose dace, and white suckers.

Have you ever put your hand into a nice clear stream in the summer and wondered how it stays so cold?  Coldwater streams are cold because they are fed by groundwater springs. The groundwater stays a steady 50 degrees all year long and provides summertime streamflow when we have little precipitation. The temperature and flows of a stream are changed when the rain hits hot blacktop in the summertime and then drains directly into a stream without filtering back into the ground. This not only makes the stream hotter, it lowers the groundwater table and thus streamflow. The fish that live in our streams are adapted to the coldwater environment but due to development there are few places in Eastern Mass left that can support species, like Eastern native brook trout, that need that cold, clear, oxygen rich water.  That is why when Eastern native brook trout are found in a stream the state designates these streams as coldwater fisheries which gives them special protections to prevent the loss of habitat.

Last year our staff scientist, Sara Grady, and the State’s Division of Fisheries and Wildlife Biologist, Steve Hurley were surveying the Third Herring Brook and found that Eastern native brook trout were using the mainstem. We had known of two remnant populations of this species in tributaries to the Third Herring Brook and we hoped that after the Tack Factory dam was removed the two populations would be connected through the mainstem.  Finding these fish in the system means that the entire Third Herring brook from Jacobs Pond down to the North River is now officially protected as a cold water fishery resource.  This means any future development or redevelopment along the brook will be held to higher standards for treating and recharging stormwater from paved surfaces to protect this critical and increasingly rare resource – cold flowing water.

Catch and release is advised for any brook trout captured in Third Herring Brook system to help protect and restore our limited wild brook trout resource.