Unalaska, AK – The Unalaska Horse Gelding Project began castrating the Summer Bay stallions this week in an effort to reduce the growth of the herd. Jeff Hancock, the manager of the project, says the horses are damaging the local ecosystem.

"Among the impacts they have on our local environment are things like causing erosion around stream beds, which causes siltation in streams. If the water is not clear running, it can impact local salmon populations, which are naturally occurring," Hancock said.

He also said that the horses put cultural sites, like old villages, at risk. "These horses tend to favor cultural sites because grass and other growth tend to grow on those sites because the soil is really rich. Lots of animal bone and shell material and so forth in these old village sites."

Volunteers with the project also say preventing herd growth is good for the horses because it cuts down on feeding pressure during the winter.

To geld them, the horses are tranquilized then operated on by Dr. Jennifer Bando, a veterinarian from Homer. She attaches an emasculating device to the testicles then cuts them off.

The project focuses on the horses living near Summer Bay on land owned by the Ounalashka Corporation and the Alaska Maritime National Wildlife Refuge. It is funded by a grant from the U.S. Fish and Wildlife Service and implemented by the Friends of Alaska's Wildlife Refuges, who work to remove invasive species from refuges around the state. Poppy Benson with Fish & Wildlife says the project is important for the Refuge but also for local land owners.

"It was a very much locally identified problem and is a locally implemented solution," she said. "Which is great, because our refuge is so huge, we've got so much going on with rats on different islands and our regular bird work, that I don't think it would have risen as a priority with the refuge. It was a priority with the people who live there."

The first phase of the project gelding the 6 stallions from the 16 horse herd will conclude this week. The group will return next summer to geld any new stallions and to check on this year's.