- File photo by Bob Hammerstrom
Hollis third-graders uses nets to catch bugs in the Souhegan River after releasing the salmon fry in this 2010 event, one of many in which area pupils have placed baby salmon in the river. No such stocking will take place this year as officials try different approaches to bringing back wild salmon to New Hampshire rivers.
- Staff file photo by Bob Hammerstrom
With the help of George May from the Atlantic Salmon Restoration Program, Revathi Nithipalan, left, and classmate Natalie Bronfine, along with more than 100 third-graders from Hollis helped release salmon fry into the Souhegan River in Milford in May 2010.
Tradition of placing baby salmon into Souhegan on hold this year
A summertime ritual for area school children, helping stock inch-long baby salmon in the Souhegan River, won’t occur this year, as fishery officials try a different tack on returning the historic fish to local waters.
New Hampshire Fish and Game Department announced last week that it would alter its 3-decade-old program of placing millions of what are known as salmon fry, born in fish hatcheries to adult fish captured as they return from the ocean, in hopes of helping naturally spawned fry thrive in the Merrimack River watershed.
This year, no hatchery-born fry will be stocked in the Souhegan River, to give officials a better view of whether adults are able to produce their own eggs that will turn into fish, which eventually swim out to the Atlantic Ocean to breed.
“This will allow us to measure the reproductive success of salmon that spawned naturally in the watershed,” said Matt Carpenter, a fisheries biologist who coordinates New Hampshire’s salmon restoration program, in a press release. “Within five years, we should have a better understanding of what to expect from salmon that are allowed to run the river. This information, along with trends in ocean survival, will ultimately determine if successful salmon restoration can be achieved for the Merrimack.”
The Souhegan is suitable for this effort since the 2008 removal of the Merrimack Village Dam at the mouth of the river, which makes spawning habitat accessible, Carpenter said.
The same number of fry will be released into New England rivers but in different locations – mostly in Massachusetts and Connecticut, where young salmon have to navigate fewer dams on their migration out to sea. When salmon return after spending several years in the ocean, they try to go back to the location where they were born, prodded by instincts that are not well understood.
The change in fry stocking is being made because the decades-old salmon restoration program has seen little success. Out of the many millions of young salmon placed in the Merrimack River watershed, only a few hundred adults have tried to return to the river from the Atlantic Ocean each year.
It’s not clear what happens to the rest, but for some reason, they are not surviving the ocean portion of their life. Determining the causes of this declining marine survival is a major focus of current research.
“If ocean survival is cyclical, then it is reasonable to believe that salmon restoration can succeed,” said Carpenter. “However, if there has been a fundamental shift in the North Atlantic ecosystem because of a changing climate or other factors, then salmon restoration may not be possible.”
Somewhat ironically, this year’s change in fry spawning was prodded partly because 2011 saw a relatively good return of adult salmon from the Atlantic. The closing of an ocean fishery off the western coast of Greenland, where Atlantic salmon congregate before migrating back to their home rivers, may have played some role.
Salmon returning to the Merrimack River are captured at the Essex Dam in Lawrence, Mass., the first dam blocking the river when going upstream. The fish are then taken to hatcheries to produce eggs for restocking in rivers.
A record number of 402 Atlantic salmon were counted at the Essex Dam in the spring of 2011, and similar increases were recorded on salmon rivers throughout Maine and Canada.
Whatever it indicates about the restoration program, those figures were a boon for fishermen last year. They were sufficient to allow Fish and Game to release several hundred adult Atlantic salmon, some as large as 16 pounds, into the Merrimack River watershed, because they weren’t needed to produce eggs and fry.
There will also be reduction in fry stocking for the Connecticut River Salmon Program due to flood damage at the White River Hatchery in Vermont during Hurricane Irene.
New Hampshire Fish and Game biologists will stock a small amount of fry in the Keene area, but said they will not need volunteers this year.
Anadromous fish – those which live part of their lives in fresh water and part in salt water – have been in trouble since the first dams went up on New England rivers 200 years ago, blocking their return to spawning grounds.
Fish ladders help, but biologists identify many other possible factors that contribute to the problems, including:
Pollution-caused acidity in streams and lakes where fish spend a year or two before heading to the ocean.
Growing numbers of striped bass, which eat young fish heading downstream to the ocean.
Commercial fishing in the Atlantic Ocean of the adult populations.
Climate change’s effect on the ocean, raising water temperatures and altering currents.
David Brooks can be reached at 594-6531 or firstname.lastname@example.org.