For more than a hundred years, the state has been stocking ponds all over the Cape and Islands with locally raised trout. Mike Clark of Plymouth helps breed these fish at a series of outdoor pools in Sandwich.
"This facility was bought in 1912 by the state. It’s one of the oldest public hatcheries in the country. It was developed in the late 1800s," he says.
Brook trout are native to local waters, and in the 1800s Cape Cod was a premier destination for catching these fish. But pollution from factories, forest clearing, mill dams, and the development of streams into cranberry bogs decimated wild brook trout populations in southeastern Massachusetts. One of the most famous rivers for Brook Trout fishing was actually the Monument River — today that’s the Cape Cod Canal. Now, it’s thought that brook trout occur in only 5 percent of their historic habitats.
"So for trout to spawn, they need fast-moving water with gravel on the bottom for them to be able to lay their eggs in," Mike says.
"If they don't have the gravel they can't spawn on sand. So you add the limited habitat available, plus the amount of dams that went in on any decent sized river and made it so there wasn't that much catchable fish."
Today, Mike and others at the Sandwich Hatchery work to replicate healthy stream habitat for trout in a series of manmade pools. Those pools are spring-fed.
"It’s all spring water, it used to entirely be artisan wells, that just means you tap the groundwater. It was kind of trial and error, they tried it down the street in Shawme Pond, it was a warm water pond, trout need cold water, it didn’t work. I don’t know how much dumb luck it was or not, but they realized it worked here and it’s been going on ever since," Mike explains.
The water in the trout breeding pools flows at about 1,000 gallons a minute. It never freezes, and it never gets above about 60 degrees, which is perfect for trout. Mike says it takes some work to keep the pools clear of moss and other vegetation.
"Anything that’s in there that’s not a trout is taking away oxygen from the trout and the more oxygen the more growth, so the name of the game here is getting the biggest fish we possibly can to make the happy fisherman."
The hatchery keeps a population of big older fish as brood stock, and each year Mike and his colleagues keep the conditions right for these fish to spawn and then hatch their eggs. They feed the growing fish a commercial grade fish food and depending on the species let them grow for a year and a half to two years. Then, it’s time to release the trout in local waters.
"We stock out here about 50,000 pounds of trout a year, that is one week of stocking in the fall, which is just rainbow trout, but then in the spring we do our big stocking for the year; it’s about 10 weeks," Mike says.
"It starts beginning of March more or less, five days a week. We have a stocking truck here that we use, so we’ll put approximately a thousand pounds of fish on a truck, and disperse them to all the bodies of water they go to."
Most of the fish stay in the southeast, essentially from Hingham to Fall River and then all of Cape Cod. The hatchery stocks trout on Martha’s Vineyard as well.
Yes, you heard that right. The hatchery loads up trucks with fish, drives them onto the ferry, and releases them across the water into ponds on the Vineyard. It’s amazing and kind of crazy. But I’ve seen firsthand how happy it makes people who love to go fishing.
"Most of the fish we release are about a pound a piece, but we do release fish over ten pounds," Mike says.
We got a two-pounder and we were really excited I told him.
"I would be happy with a two-pounder myself," Mike says.
Learn more about the trout stocking here.
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This piece first aired in May 2022.
