“This year Kodiak hatchery fish added up to more than $6 million for fishermen, and also for sportfish, subsistence and personal use fisheries,” Tina Fairbanks, director of the Kodiak Regional Aquaculture Association, said in testimony to the Kodiak Island Borough after one of the island’s poorest salmon seasons.

But Alaska’s hatchery program, which has operated since the early 1970s, is under assault by critics who claim the fish are jeopardizing survival of wild stocks.

A Kenai sportfishing group said in statements to the Alaska Board of Fisheries that “massive releases of pinks from Prince William Sound hatcheries threaten wild sockeye and chinook salmon” bound for their region. An individual from Fairbanks is calling for a decreased cap on how many pink salmon some hatcheries are allowed to release to the ocean each year.

Currently, 29 salmon hatcheries operate in Alaska, producing primarily chums and pinks. Twenty-five are operated by private nonprofit corporations funded by the sale of a portion of the salmon returns. Two sportfish hatcheries are operated by the state at Fairbanks and Anchorage, one research hatchery is run by NOAA Fisheries, and one is operated by the Metlakatla Indian Community.

Alaska hatcheries don’t grow fish to adulthood, as fish farms do. They can be likened more to salmon maternity wards, where fertilized eggs from local stocks are incubated until they become big enough to be let out into the world.