MONTPELIER, Vt. – The U.S. Fish and Wildlife Service is disposing of 434,000 lake trout from a Bethel fish hatchery because of fears that stocking them in the Great Lakes could spread the invasive algae known as “rock snot.”

Officials tried to find alternative locations where the 4-inch fingerlings could be stocked into waters already contaminated with the algae, known more formally as didymo, including lakes in Vermont and New Hampshire, but none could be found, said Fish and Wildlife spokeswoman Terri Edwards.

“Everyone at the hatchery is upset. This is not the choice that we wanted to make,” she said. “We did not want to take the risk of introducing didymo into any environment.”

The decision to destroy the fish was made by the Fish and Wildlife Service’s Northeast regional director, Wendi Weber, who determined they could not be safely stocked in lakes Erie and Ontario — where they were supposed to be released — without posing a risk that didymo could be transported to those bodies of water.

Federal official asked counterparts in states across the Northeast and around the Great Lakes for a lake that had already been contaminated with didymo where the fish could be released.

“In the end, we were not able to place them,” Edwards said.

The fish are being taken out of their tanks and dumped into deep pits where they are covered with lime and buried. They pose no public health threat, Edwards said.

Didymo is believed to be transported by anglers moving from one body of water to another. It poses no threat to humans but can overwhelm cold water lakes and streams, threatening aquatic insect and fish populations by smothering food sources.

The hatchery is located on the banks of the White River, which is known to contain didymo, and was inundated by contaminated river water during flooding in August caused by Tropical Storm Irene.

Last month, about 3,000 larger Atlantic salmon breeding stock from the hatchery were cleaned and donated to several Native American tribes. Some tribes used them as part of religious rituals.

Once the lake trout have been removed from the hatchery, the tanks will be scrubbed and disinfected to be sure no threat of didymo remains. The water in the hatchery’s tanks comes from wells.

The fish originally were raised to be stocked in lakes Ontario and Erie next year. While the fish will be missed, over time their absence isn’t expected to hold back the stocking programs for the Great Lakes, Edwards said.

In 2011, the Fish and Wildlife Service stocked more than 4 million lake trout in the Great Lakes.

It’s unclear how long the Bethel hatchery will be out of service or what its role will be once repairs have been completed. In addition to disinfecting the tanks, other repairs from Irene damage are also being carried out.

The loss of the Bethel hatchery comes as the Allegheny National Fish Hatchery in Warren, Pa., goes online after being out of service for several years. The Warren hatchery, originally established to produce rainbow, brook and brown trout for northwestern Pennsylvania streams, now is intended to produce lake trout for restoration in lakes Erie and Ontario.