Fish Facts » Atlantic Salmon
The coloration of young Atlantic salmon does not resemble their adult stage. While they live in freshwater they have blue and red spots. While they mature they take on a silver blue sheen. When they are adults the easiest way of identifying them is by the black spots predominantly above the lateral line, although its caudal fin is usually unspotted. When they reproduce males take on a slight green or red colouration. The salmon has a fusiform body, and well developed teeth. All fins, save for the adipose, are bordered with black.
The Atlantic salmon is an anadromous species, living in fresh water for at least the first 2 or 3 years of life before migrating to sea. Relatively large cool rivers with extensive gravelly bottom headwaters are essential during their early life. Smolts migrate to sea where they may live for 1 or 2 years before returning to fresh water. The movements of Atlantic salmon at sea are not well understood. Tagging has shown that while some salmon wander, the great majority return to the river in which they were spawned. When at sea, salmon seem to prefer temperatures of 4 to 12 C. They may withstand exposure to temperatures in their lower lethal limit (-.7 C) and their upper lethal limit (27.8 C), but only for a short period of time (Bigelow, 1963).
Juveniles start with tiny invertebrates, but as they mature they may occasionally eat small fish. During this time they hunt both in the substrate, and also those in the current. Some have been known to also eat salmon eggs. The most commonly eaten foods include caddisflies, blackflies, mayflies, and stoneflies. In adulthood, fish feed on much larger food: Arctic squid, sand eels, amphipods, Arctic shrimp, and sometimes herring. During this feeding time the fish's size increases dramatically.
The average size of Atlantic salmon is 28-30 inches (71-76 cm) long and 8-12 pounds (3.6-5.4 kg) after two years at sea. Although uncommon, adults can grow to be as large as 30 pounds (13.6 kg).
The Atlantic salmon is native to the basin of the North Atlantic Ocean, from the Arctic Circle to Portugal in the eastern Atlantic, from Iceland and southern Greenland, and from the Ungava region of northern Quebec south to the Conneticut River (Scott and Crossman, 1973).
University of Michigan Museum of Zoology Animal Diversity Web, Wikipedia
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