BELFAST, Maine — This spring, birder and wildlife photographer Bill Brown of Sierra Vista, Arizona, happened to be at Belfast’s Kirby Lake when several ospreys flew down for a snack.

One of the ospreys dove under the water of the small pond — better known locally as the Muck — and surfaced with a bright orange goldfish clutched in his claws. In the photos Brown snapped, the large goldfish would clearly become a satisfying mouthful for the osprey. Full-grown osprey can be up to 24 inches long and have wingspans of almost 6 feet across.

“Great place to see birds, especially the three osprey that showed up for brunch,” Brown, formerly of Maine, said on his Facebook page about his morning at the Muck. “It was pretty cool watching them do their thing.”

But if “their thing” is diving for giant goldfish, the Maine Department of Inland Fisheries and Wildlife is hoping that they will stop doing it soon. The state agency has proposed to the city that the Muck, a spring-fed pond at the intersection of Miller Street and Lincolnville Avenue, be reclaimed for youth recreational fishing. In order for that to happen, Maine Game Warden Chris Dyer said in late summer that the city will need to dredge the pond so that it is at least 10 feet deep — and get rid of the goldfish.

The goldfish, which are not native to Maine, apparently have been dumped in the Muck by generations of schoolchildren and others who have grown tired of taking care of their pet fish. Many have survived, with some growing to sizes as big as 2 feet long, according to local lore.

“It’s against the law to have goldfish in a pond,” Dyer told the BDN then. “They can be transported by people or other animals. It could be a very big issue. They reproduce like the dickens — we can’t have it.”

Norm Poirier, the parks and recreation director for Belfast, said Tuesday that he has gotten an optimistic estimate for the cost of renting an excavator with a 75-foot reach for a week.

“I think it’s reasonable,” he said, declining to share the cost estimate publicly but adding that an excavator operator has offered to provide both fuel and services to the city for free.

Poirier said he is waiting for some information from the DIF&W before he goes to the Belfast City Council to ask if they will approve the project. He wants to know if the pond is likely to require further dredging in a few years, which would be undesirable from the city’s standpoint. He also would like to know if the city of Belfast is obligated by law to do something about the goldfish in the pond.

“If we have some responsibility because we’re the owners of the property, we have to do what’s required of us,” he said, adding that he expects to bring the question to the Belfast City Council in about three weeks. “If we are not required to take some action, we have a choice.”

He said that he has received quite a few calls in favor of the new direction for the Muck. But the city also has heard from a couple of people — not Belfast residents, Poirier said — who are concerned about the fate of the goldfish. He said they would prefer that the city not kill the fish.

“I told them if you can find a resource for us to transport them to, please let us know,” Poirier said.