Commercial salmon fishing was closed Thursday in Bristol Bay's Nushagak district after a sunken boat was found to be leaking fuel.

The Alaska Department of Fish and Game on Thursday responded to a report of fuel spilling from a tender that sank at Clark's Point. In an aerial survey, a Fish and Game crew "observed significant amounts of fuel spreading out from the site of the sunken vessel," the agency said in an alert.

"This fuel was already pooling in tide rips and is likely to spread across the bay with the wind and back toward Dillingham as the tide begins to flood," the agency said.

"Because there is a significant chance of gear and fish being exposed to fuel we are closing the entire Nushagak District to all commercial fishing."

The sunken fishing vessel, named Pacific Knight, capsized Wednesday in Nushagak Bay, according to the U.S. Coast Guard. A good Samaritan crew aboard the fishing vessel Amanda C rescued two people from the water, the Coast Guard said.

Wednesday evening, the agency suspended its search for a third person, a man reported missing after the capsizing.

Nushagak is one of five districts in Bristol Bay, the largest commercial sockeye salmon-producing region in the world. Earlier this month, Bristol Bay sockeye catches were breaking records as other Alaska fisheries struggled.

The sockeye run in the Nushagak district is mostly over at this point in the season. Bristol Bay is also winding down as a whole for sockeyes.

"We're on the tail end of the biggest run we've ever had" in the Nushagak district, said Tim Sands, a biologist with Fish and Game. "We were hoping to have some additional opportunities for pink and coho salmon, but we haven't seen a big uptick in pink and coho catch yet. Hopefully we'll be able to start fishing again in a couple days, maybe sooner than that."

An estimated 800 gallons of diesel and 300 gallons of hydraulic fluid was

on board when the vessel sank, according to a report Thursday afternoon from the Alaska Department of Environmental Conservation.

"At this time it is unknown how much has spilled," the report said. There was no source control as of Thursday afternoon, according to the report, and "a sheen is emanating from the sunken vessel."

A dive team is scheduled to dive on Pacific Knight at 9:30 p.m. Thursday to assess the situation, the report said. The cause of the capsizing is under investigation.

Subsistence fishermen on Dillingham beaches should also be aware of the potential for their fish and gear to be contaminated, the Fish and Game announcement said.

"We will continue to monitor the situation and consider reopening commercial fishing when there is no longer a danger of contamination," the agency said.