Experts worry as herring get stuck on Upper Mystic Lake Dam spillway

Fish are getting stuck on the dam at the Upper Lakes Dam on the Medford and Arlington line and becoming bird food.

Herring experts worry that all the work to help rebound the population will see a significant setback if fish can't make it downstream.

As a large amount of fish get stuck on the spillway of the Upper Mystic Lake Dam, birds are taking the opportunity to sweep in.

The state says it's working on a long-term plan to re-direct the fish where they should be going.

"We're making it too easy for the birds," said Patrick Herron, the Executive Director for the Mystic River Watershed Association. "Birds are good at hunting their own fish, let's not put it on a plate for them."

Herron, the head of the Mystic River Watershed Association, a non-profit educational and advocacy group, says the herring are first supposed to swim upstream using a fish ladder built into the dam.

"[Herring] live in the ocean, but they come into freshwater to make the next generation," said Herron.

The fish then head downstream using a trench along the side, but Dr. Herron says fish are getting stuck on the spillway, where the water is only and inch or two deep.

"So there needs to be some optimization to direct the fish away from that spillway so we are not putting them on the plate for the birds if you will," said Dr. Herron.

Environmental officials say the number of herring overall has gone up drastically because of this project. In the past five years, population has gone from about 200,000 herring up to 630,000.

Dr. Herron is concerned this issue will impact the rebounding population, which is why they've alerted the state about it.

DCR officials told Boston 25 News on Monday they are working on a long-term fix.

Sandbags will be placed on the top of the spillway to help direct the fish to the correct location and give them a better chance to get back out to sea.

"If we can increase the population of river herring off the coast, we're likely to see positive impacts for these other species," said Dr. Herron.

Cox Media Group