Thanks to several weeks of hot, dry weather, Maine’s rivers are at or near record low levels, and that’s bad news for blueberry growers and Atlantic salmon.

On Sunday afternoon, the flow of water in the Penobscot River tied the lowest flow rate that had ever been recorded on Aug. 12. Five of the eight rivers that are home to endangered wild Atlantic salmon had record low flow rates.

The number of years flow records have been kept by the U.S. Geological Survey varies by river. On some rivers records have been kept for less than a decade and on others it’s been more than 100 years.

Sunday’s flow on the Narraguagus River in Washington County, for example, was 26 cubic feet per second. The previous low recorded on that date was 32 cubic feet per second. Records have been kept on this river for 53 years.

In midcoast Maine, the flow of the Sheepscot River on Sunday afternoon was 12 cubic feet per second, below the previous low of 14.

Both rivers are home to Atlantic salmon populations that were put on the federal endangered species list last year.

The Penobscot River in West Enfield was flowing at a rate of 3,300 cubic feet per second, tying the lowest level recorded for Aug. 12. The Penobscot has been monitored by the USGS for 98 years.

“In some cases, we’re setting daily flow records and we’re not expecting any relief,” said Bob Lent, district chief for the USGS in Maine.

He said the situation is expected to worsen because river level typically drops in the last couple weeks of August, which are usually the driest of the summer.

The only parts of the state where rivers are not at record low levels are in extreme eastern Washington County. In the Dennys River, another salmon river, for example, water was flowing at a rate of 50 cubic feet per second, well above the record low of 15.

Flow in the St. Croix was also well above record lows.

The low river levels mean less water is available to irrigate the state’s wild blueberry crop.

“We don’t have as much water as we need with this type of weather,” said Dave Bell, executive director of the Wild Blueberry Commission of Maine.

Three weeks ago, blueberry growers were predicting a near record crop of 108 million pounds. That was before the hot weather set in and the rain stopped falling. Now harvest predictions are likely to be revised downward.

Because of the drought, some fields owned by Jasper Wyman & Sons in Washington County simply won’t be harvested because the berries have withered, said Fred Olday, the company’s director of farm research. On Friday, the company did not know how many barrens would remain unharvested.

Because wild Atlantic salmon in five Down East rivers have been declared an endangered species, water withdrawals from them are limited. Large blueberry growers have been moving to irrigation systems that use wells and storage ponds to reduce their reliance on river water. But the companies still take water from the rivers, when it is permissible, to refill their supplies.

Wyman for example, takes water from the Narraguagus to replenish its storage ponds. It has been allowed to take water from the river only three times since June 27.

“We try to be good corporate citizens. We don’t want to negatively impact the salmon,” Olday said. But not being able to take river water means fewer, smaller blueberries for the company.

The company is not now able to water some of the fields that will bear fruit next year. Those fields are drying up, so next year’s crop may well suffer from this year’s lack of water, Olday said.

The biggest problem, he said, is not with federal regulators trying to protect wild salmon, but with camp owners who don’t want lake levels to drop so that blueberry fields can be watered.

Both Wyman and Cherryfield Foods Inc. are allowed to withdraw water from Schoodic Lake, which is north of Cherryfield and Harrington. Since the lake is partially in unorganized towns and an unorganized township, different portions of the lake are governed by different regulations. Cherryfield Foods takes water from the side of the lake that is regulated by the Land Use Regulation Commission. Because of the lack of rainfall, it has been told by the agency to stop withdrawing water from the lake.

Wyman’s withdrawals from the same lake, on the other hand, are covered by Department of Environmental Protection regulations. Although the company has not been told to stop pumping water out of the lake, it has done so because some camp owners have complained to the DEP about low water levels.

“Camp owners should be more sensitive to our needs,” Olday said, noting that some exposed shoreline is less of a problem than a dead blueberry crop.

Despite concerns that the hot, dry weather will harm them, the state’s small population of Atlantic salmon has not been dramatically affected – yet.

Salmon have strategies to cope with warm weather, said Norm Dube, a biologist with the Maine Atlantic Salmon Commission. He said they seek out cold pockets in streams and rivers and will burrow under rocks to keep cool.

Still, “not every salmon will escape this type of weather,” Dube said.

Ken Beland, another biologist with the salmon commission, said there have been reports of dead juvenile fish.

The full impact on salmon won’t be known for several weeks, said John Kocik, director of salmon recovery for the National Marine Fisheries Service. It is possible that fewer salmon were born this summer, but it is too early to count them because they are still too small to be caught. Such counts will be conducted in late August and September.

On the positive side, the warmer weather sometimes means that fish returning to their native rivers remain in the colder seawater longer. This means that more fish will come back to Maine later than usual.

“There is reason to be optimistic,” Kocik said.