Cormorants

During the course of normal spring field operations DMR biologists have commonly observed increased cormorant activity at Penobscot River dams coinciding with the spring emigration of wild juvenile Atlantic salmon smolts and the release of hatchery smolts produced at Green Lake National Fish Hatchery. Biologists, Maine State Game Wardens, and dam personnel have observed cormorants preying upon smolts that are holding above dams and below. Double-crested cormorants have long been recognized as important predators of smolts and post-smolts emigrating out of Maine rivers. Studies demonstrated that smolts are often among the most frequent prey items of double-crested cormorants in the Penobscot River during smolt emigration. Further, cormorants seem to prefer foraging near dams where they target migrating smolts congregating above dams, and on smolts that have gone through the dam and consequently are often disoriented.

Staff are participating in a cooperative project with U.S. Department of Agriculture Wildlife Services to deter cormorant feeding at dams during smolt emigration. The project protects the investment of federal dollars rearing smolts and hopes to increase survival of smolts from stocking through the Penobscot estuary and to increase returns rates of smolts to adults. NOAA Fisheries is cooperating with U.S. Department of Agriculture Wildlife Services on a comparable project on the Narraguagus River, where the goal is protecting wild smolts from one of the rivers in the Endangered distinct population Segment.

DEPT. OF MARINE RESOURCES

Cormorants