Montshire Minute: Atlantic Salmon

Originally aired during the week of August 2, 1999

Monday

Look! Up in the sky . . . It's a bird . . . It's a plane . . . It's a . . . fish? Well, the Atlantic salmon doesn't fly, of course, but sometimes it seems that way when it makes its way up the Connecticut River. The Latin name for Atlantic salmon, Salmo salar, means "the leaper." An adult Atlantic salmon averages 30 inches in length and weighs from 7 to 12 pounds. In the right conditions, adult Atlantic salmon can leap up to 12 feet over obstacles. That's more than two six-foot tall people standing one on top of the other. So why would a fish need to leap that high? Atlantic salmon are anadromous (ah-nad-rah-mus) fish: They are born in freshwater, live in the ocean, and return to the rivers, their birthplace, to reproduce. For their annual spring migration, adult Atlantic salmon must swim upstream over dams and falls. Being able to leap helps them to beat this watery obstacle course.

Tuesday

There's a bog difference between Pacific and Atlantic salmon. Pacific salmon die after migrating back to the river to spawn. Atlantic salmon, on the other hand, do not always die and can return to the ocean. When adult Atlantic salmon or "sea-run" males and females migrate in the spring, they stop eating when they reach freshwater and live off their own body fat and tissues - sometimes for up to a year. This is a pretty amazing feat if you consider that adult Atlantic salmon have to travel thousands of miles from their feeding grounds in the North Atlantic up the Connecticut River watershed to spawn. Fortunately, they have a break between migrating and spawning: Adult salmon spend the summer hanging out in colder areas of the river, moving to gravelly tributaries to spawn in early fall.

Wednesday

It might not sound like an ideal spot for a nursery to us, but Atlantic salmon need to find gravelly tributaries to spawn. In the early fall, adult female Atlantic salmon bury their eggs in gravel nests or "redds." After the eggs hatch in March and April, the baby salmon or "fry" hide out in the gravel for a few weeks before venturing out to feed. Young salmon or "parr" spend one to three years in their birthplace before undergoing the salmon equivalent of adolescence: "Smolts" (as the salmon are now called) undergo physical changes so they will be able to live in saltwater. They become silvery in color, and migrate to the ocean. The smolts travel thousands of miles to their feeding grounds in the North Atlantic and stay there for one or two years until the return to their birthplace in the Connecticut River watershed to reproduce.

Thursday

Since the late 1700s, dam construction along the Connecticut River gradually cut off salmon from their spawning grounds. Salmon have long been absent from the river, but recent efforts by the US Fish and Wildlife Service and other groups have been launched to reintroduce the fish into the Connecticut River. Among other things, state and federal agencies create fish elevators or ladders and stock juvenile Atlantic salmon in the Connecticut River watershed. Happily for fishermen, stocking Atlantic salmon does not detrimentally affect the trout which also reside in the Connecticut River: Salmon tend to live in shallow, fast-moving water while trout live in quieter pooled areas. In fact, Atlantic salmon co-exist particularly well with brook trout, the other native trout species or "salmonid" in the Connecticut River watershed.

Friday

Going up? A fish elevator sounds like a rather posh arrangement for weary salmon tired of leaping. Actually, it's not really if you consider that you're sharing elevator space hundreds of other fish. Fish elevators lift Atlantic salmon and other anadromous fish over dams, man-made obstacles which would otherwise be impassable. The elevators lift the fish 52 feet into the air over the Holyoke Dam into the Connecticut River, transporting as many as 2,000 fish each hour. After the elevator ride, migrating fish still need to climb up a fish ladder at Turners Falls. This consists of a series of pools simulating the natural rises of a river before dams were built. To learn more about the Connecticut River watershed and the life cycle of the Atlantic salmon, visit the Stevens Aquatic Center at Montshire and Our Place, an exhibit sponsored by the US Fish and Wildlife Service.