River Specific Stocking
Mature Adult Salmon
NMFS Northeast Fisheries Science Center
N E W SOctober 25, 2000, Woods Hole, Mass. -- Federal and state biologists plan to release 125 adult salmon in the St. Croix River tomorrow (October 25). The fish are the last of more than 1,000 pen-reared adult salmon released this month to help rebuild the population of wild salmon living in three Maine rivers. The stocking project marks the first time in the United States that mature, pen-reared adult salmon have been stocked back into their natal rivers.
"This is a collaborative effort of industry and state and federal agencies," said John Kocik, a National Marine Fisheries Service (NMFS) biologist who chairs Maine's Salmon Technical Advisory Committee. "The release of the fish is only the beginning – we'll be working with the Atlantic Salmon Commission to monitor these fish and to learn more about how stocking programs can help rebuild self-sustaining salmon populations."
The release of the fish was coordinated by Tim Sheehan, also a NMFS biologist, and Randy Spencer and Greg Mackey of the ASC.
The fish were taken from captive broodstock from the Dennys, Machias, and East Machias river populations. The project began in February, 1997 when the U.S. Fish and Wildlife Service (USFWS) transferred 60,000 eggs from the Craig Brook National Fish Hatchery to the hatcheries of private aquaculture companies. The transfer of eggs from the federal hatchery system to private aquaculture facilities is part of Maine's Atlantic Salmon Conservation Program and is an attempt to use industry facilities and expertise to help rebuild wild stocks.
The eggs were hatched and raised to smolt-stage in freshwater hatcheries (smolts are young salmon that migrate downstream to make the transition to become salt-water fish). Some of the fish were stocked as juveniles in the spring of 1998.
Other smolts in the stocking program were transferred to salt-water net-pens where they spent two years before they were released this month as pre-spawning adults, ranging from 9-30 pounds. The adult fish were stocked into the Dennys, Machias, and St. Croix rivers near suitable spawning habitat.
The biologists hope the stocked salmon will spawn in the rivers and produce offspring that will be reared entirely in the wild. One goal of the stocking project is an increase in the number of juvenile salmon and ultimately the number of returning mature adult salmon in these rivers.
"This is also a chance to learn about how these adults fare in the river," Sheehan said. "Our first evaluation will come later this fall when we measure the spawning success and examine the movements of these fish with ultrasonic tracking equipment."
Teams of federal, state, and private salmon experts will monitor the stocked salmon's spawning behavior and choice of habitat. The biologists will compare the performance of the adult stocked fish with wild salmon and with salmon reared in freshwater hatcheries. The studies will continue for 5-6 years to determine what the stocked fish do after spawning and to monitor how many fry (young salmon) the stocked fish produce. Eventually the biologists will evaluate how successful the offspring are at reproducing, the ultimate test of success.
The stocking project is a partnership between federal agencies (NMFS and USFWS), Atlantic Salmon of Maine, Connors Brothers Aquaculture, Inc., Stolt Sea Farm, Maine Atlantic Salmon Commission, the St. Croix International Waterway Commission, and the University of Maine.