The landlocked Atlantic salmon (Salmo salar) is one of the most prized game fish in the Northeast. First found in Maine and southeastern Canada, it may be native to Lake Champlain and has since been distributed throughout North America and Europe.
There are no physical differences between the landlocked Atlantic salmon, which spends its entire life in fresh water, and the sea-run Atlantic salmon, which spends most of its adult life in salt water. Both are leapers and keeps the angler's adrenaline flowing.
Adult salmon prefer clear cold lakes with maximum temperatures around 70° to 75°F. In the spring, adult salmon use the relatively warmer water near the surface, and will move to cooler deeper water as summer progresses. A pH around 6.0 to 7.0 is needed for salmon to thrive. A lake needs to have streams with adequate spawning and rearing habitat to sustain a naturally reproducing population.
For spawning, the female selects a site within an inlet or outlet stream of its resident lake that has gravel rather than silt or sand on the bottom. Good spawning habitat also has layers of stones that are about 1/2 to four inches in diameter. Nursery habitat includes primarily shallow water interspersed with deeper pools and riffles. Large pebbles or rocks and vegetation are also present to provide the young salmon with food and cover. Well-oxygenated water is important, as is the water temperature. Optimal fish growth occurs in streams with peak temperatures of 72° to 77°F. The cooler the water, the slower the growth of the fish.
Adult salmon spawn in October and November using the inlet or outlet streams of their resident lake. Female salmon generally reach maturity during their fourth or fifth year. Males develop faster, maturing by their third or fourth year and even as young as one and two-year olds. At breeding time, the lower jaw of the male grows a prominent, turned up hook called a "kype."
Individual salmon may spawn annually or every other year. Some may spawn for two consecutive years and then skip a year but studies indicate that these individuals are primarily alternate year spawners. Up to 90% of a spawning run, however, consists of salmon spawning for the first time.
Spawning salmon prefer gravel riffle areas, just above or below pools in swift moving water to assure proper oxygenation of the eggs. The female salmon excavates a series of pits and covers them with gravel, which is known as a redd, in an area with little silt or sand. She may dig several egg pits over a week's time to contain her eggs.
The eggs are deposited at night in the gravel at a depth of four to twelve inches. A single female produces 600 to 700 eggs per pound of her body weight. The male swims alongside the female and fertilizes the eggs, by releasing milt, a milky white fluid that contains sperm, into the water. The egg incubation period averages 150 days although it varies in different areas according to water temperatures.
After hatching, "sac fry", or alevins, remain in the gravel, living off nutrients absorbed from the yolk sac, until their yolk sac is gone, usually in late April. Then the young fry work their way up through the coarse gravel into the riffle and boulder areas and start to feed on aquatic insects. Once they reach two inches in length, the fry develop dark bars, or parr marks, on their sides. At this life stage they are called parr. Both fry and parr use rocks, woody debris and vegetation for cover from predators in fast moving water.
Young salmon spend one to three years in the stream before another physiological change takes place. The fish get the urge to move to larger waters, and prepare to do so by transforming into smolt. The smolt migrates to the lake. Once in the lake, its growth rate increases rapidly.
Growth rates vary from lake to lake, but in Vermont, salmon grow best where smelt are abundant. Within one to two years after smolting occurs, an adult reaches sexual maturity, and continues the salmon life cycle by spawning.
Most landlocked salmon caught by anglers are two to four-year olds, although the oldest landlocked salmon on record, taken in Maine, was thirteen years of age. Annual mortality rates range from 40 to 60%. In lakes with a good salmon fishery, anglers probably account for about 20 to 30% of this mortality.
The Landlocked Salmon's diet depends on its developmental level and food availability. Alevins feed on the yolk sac that is attached to its belly. Fry and parr feed on small aquatic insects, larvae and nymphs of water dwelling flies like the mayfly and caddisfly. Smolts feed mainly on fish, supplementing their diet with insects from the water surface. Adult landlocked salmon feed mainly on fish, smelt. In addition, the adults will also forage insects from the surface of the lake.
The Landlocked Salmon fisheries around the state are healthy, but anglers should realize that these fisheries are largely supported by stocking of sub-legal one and two year old fish. Spawning salmon need large tributaries with good habitat and few competing species, and most of our salmon lakes do not have them. Unfortunately, small fish are more readily caught than large ones, and anglers should learn how to properly release sub-legal-size fish so they will survive.
The majority of lakes stocked in Vermont are in the Northeast Kingdom, with the exception of Lake Champlain, Lake Dunmore, and Harriman Reservoir. A fish passage facility is maintained on the lowest Winooski River dam to allow adult salmon access from Lake Champlain to the spawning habitats upstream of the dam.
All lakes are stocked with one and two year old smolts. In addition, the Clyde River (a tributary of Lake Memphremagog) and the Huntington River (a tributary of the Winooski River) are stocked with fry, and larger parr are stocked in the Winooski River. Smolt, fry, and parr stocking are being evaluated to assess their success in providing fisheries for landlocked salmon and/or establishing naturally reproducing populations.
Land-locked Salmon are ranked at a Medium Priority on the Species of Greatest Conservation Need list that has been developed by the department, and is described in the Wildlife Action Plan.