BETHEL – Volunteers using floating trout pens attached to canoes and drift boats will stock the Upper Androscoggin River from Gilead to Bethel this week with more than 1,000 yearling brown trout and older, larger rainbow trout.

The joint float-stocking program on Thursday will be conducted by the Upper Andro Anglers Alliance and the Maine Department of Inland Fisheries and Wildlife using volunteers from the Mollyockett Chapter of Trout Unlimited.

The first group of boats will leave from the Gilead boat launch at 9 a.m. and release fish to West Bethel. The second flotilla will stock from West Bethel to Bethel.

Using the float-stocking method, fish are floated downstream and released into likely hiding places and feeding habitats, according to alliance spokeswoman Wende Gray of Bethel.

“The fish are extremely vulnerable to natural predators as well as wily fishermen,” Gray said Monday in a report. “With traditional stocking methods of dumping directly into one location, brown and brook trout may not migrate up or downstream from the original stocking location for weeks.”

Heavy plastic buckets will be used to help decrease stress on the fish and to prevent mortality. Programs in Missouri, Arkansas and New York have resulted in lower initial mortality, longer duration fisheries and higher holdover, Gray said.

Fifty years ago, the Androscoggin from Berlin, N.H., to its confluence with the Kennebec River was one of the top 10 most polluted rivers in the nation.

After environmental cleanup by federal, state and municipal agencies, the Upper Androscoggin River today is an emerging angling destination. The cleanup has allowed Inland Fisheries and Wildlife to conduct an aggressive recovery program.

The department continues to stock rainbows to supplement wild stocks while brown trout are liberally stocked, Gray said.

To learn more about angling opportunities on the Upper Androscoggin, the alliance offers a brochure with a map showing access points, fishing regulations, water level information and a list of guide services and accommodations. For more information about the float-stocking trip or the Upper Andro Anglers Alliance, call 877-275-3363 or visit www.upperandro.com.