RUMFORD – Suspended sediments flushing down the Androscoggin River following last week’s catastrophic rain storm in Bethel, Gilead and Newry aren’t going to harm big fish at all. It’s the little guys – the fry – that will be more susceptible to stress and death, according to state fisheries biologists.

The bigger problem, however, is if pollutants, toxins or nitrogen-rich fertilizers were swept along in the soup, Maine Department of Inland Fisheries and Wildlife spokesman Mark Latti said by phone Thursday afternoon in Augusta.

“Silt in the water by itself, generally, doesn’t present much of a hazard to the fish,” he said, attributing his information to Peter Bourque, the department’s director of fisheries. “However, if pollutants or other toxins got washed in, that can potentially cause fish kills. But there haven’t been any fish kills yet.”

The plume of sediment making its way down the Androscoggin and into Lewiston-Auburn and Brunswick first appeared in Rumford, Mexico and Dixfield on the morning of July 12, the day after several inches of rain fell within a span of 45 minutes farther upriver.

“I live in Brunswick and I can’t believe how brown it is. It’s coffee-colored,” Latti said.

The storm flooded the Chapman Brook watershed in Bethel and Newry, washed out road shoulders and three bridges, culverts and driveways. It sent mud slides across roads and eroded parking lots, washing soil and everything in it into the Androscoggin.

Concerns about that much silt involve fish spawning areas, tributary confluences and deep water pools. Settling sediment can fill deep pools and places in streams where fish summer because the water is cooler.

Suspended silt in a river doesn’t increase water temperature short term, but there is a potential it could warm water if the soil particles don’t filter out quickly, Latti said.

Ecological and fish management problems can also result from flooding if different fish species are swept from one watershed into another where they could wreak havoc with other fish.

“It’s never really been documented, but fish do get washed out,” Latti said.

This spring, the department stocked the Androscoggin with rainbow, brown and brook trout but those hatchery-raised fish, which range in length from 6 to 16 inches, won’t be affected by the muddy water. Neither will bass, fisheries biologist David Boucher said Thursday afternoon in Strong.

It’s the fry and the first-year broods that will be damaged, but the effect won’t be seen for a few years, both Boucher and Latti said.

“Perhaps the most dramatic thing is that we may lose this year’s brood of rainbow trout, which are in those little streams that flow into the Androscoggin,” Boucher said. “If those streams had a series of blowouts, it may have washed those trout out.”

“It’s like when you have a drought. During droughts, fish die because it’s very difficult for the young of the year to survive. And that means that a couple of years later you wouldn’t be catching fish 6 to 8 inches long, or 12 to 16 inches long. It depends where they were at size-wise when the flood happened,” Latti said.