As calls grow among some members of Alaska's Bristol Bay community to close the lucrative salmon fishery this summer, other have expressed concern about not only the economic impact, but the potential biological effect on the salmon run itself.

The bay, which annually welcomes some 40 million sockeye salmon back into its waters, supports a fishery worth around $300 million (€274 million) in ex-vessel value. The fishery is a major economic engine for the region and seafood companies operating in the state, and a source of income for nearly 3,000 fishing permit holders.

Officials with the City of Dillingham and some tribes in the area, however, have said opening the fishery this season poses too high of a risk, and exposes the communities to a potentially devastating outbreak of coronavirus.

Opponents to the move, several of which have taken to social media to share their views, are raising concerns a lack of harvesting could end up harming salmon populations, whose numbers have been carefully managed by the Alaska Department of Fish & Game (ADFG) over the years.

ADFG's challenge each season is to ensure that sufficient numbers of salmon move up into rivers to spawn -- known as "escapement" -- to support the future populations. But without a harvest, the escapement figures would be significantly higher.

ADFG Area Management Biologist Tim Sands sent out an email last week highlighting the debate, and noting that "over and over again" he's heard one question: "What would happen if there was no fishing this summer, would the over escapement destroy the Bristol Bay salmon run?"

Bert Lewis, ADFG regional supervisor in the Division of Commercial Fisheries, told IntraFish "over escapement" would indeed be the primary issue to be concerned about, since theoretically it could create an excess number of juveniles that might lead to a lack of sufficient food. But that outcome with one year's closure would be highly unlikely, he said.

"In Bristol Bay, there is mitigation because there are so many big lakes that have the capacity to absorb a large number of juveniles," he said, noting the fishing region has seen numerous years with river districts seeing returns where fish have exceeded escapement goals.

The Bristol Bay area is divided into five management districts-- Naknek-Kvichak, Egegik, Ugashik, Nushagak, and Togiak -- that correspond to major river systems.

Sockeye salmon escapements by some amount over the upper end of the escapement goal generally have had a limited influence on future sockeye salmon production, according to ADFG research.

"The biological concern with a year of even zero fishing, it's pretty low," he said.

Milo Adkison, a fisheries professor at the University of Alaska Fairbanks, told IntraFish Bristol Bay also benefits from being a large, diverse system.

"You really have to have drastic effects of crowding, like using up all the oxygen in the gravel or getting a fungal outbreak before you end up with fewer total fish in the future," he said.

"Evidence from lake cores is that salmon escapement levels before commercial fishing started were at least double what we currently have. The salmon handled high escapement just fine back then. The bears and trout probably benefited greatly."

The worst case scenario if the season closes this year is a slight reduction in production, he said. "I think a good return is more likely," he added.

Over escapement could become a concern if the fishery were to be closed for several seasons, according to ADFG.

When escapements exceed the upper end of the escapement goal range, for example by two to three times, multiple years in a row, then future production and yields have been observed to decrease in some instances, research by the department has shown.

The odds of the coronavirus crisis extending beyond this Bristol Bay fishing season are outside any of the worst case projections for the disease, however.

No plans for closure

So far Alaska Governor Mike Dunleavy has kept this year's Bristol Bay fishery open and on schedule for June. But even with the fishery set to open, ADFG is preparing for a smaller season.

"It’s likely the scale of the fishery is going to be reduced," Lewis said, noting there will be less processing capacity for the fish due to coronavirus-related staffing issues as well as a reduced number of out-of-state permit holders expected to fish this year.

Bristol Bay is a magnet for people in the summer, with a seasonal migration of about 13,000 workers for the lucrative fishing season, KTOO reports.

"We’re in the process of contingency planning for incremental levels of restriction," he said.

The sockeye salmon harvest in Alaska's Bristol Bay region is projected to fall nearly 14 percent in 2020, to just over 36.9 million fish.

The overall run is forecast to be 6 percent higher than the most recent 10-year average of 45.9 million fish in the Bay, and 23 percent above the long-term average.

All of the bay's river systems are expected to reach escapement goals in 2020.