Salmon originally the big fish is now generally called Atlantic salmon (Salmo salar), although more recently the name has been applied to similar fish in the same family (Salmonidae), especially Pacific salmon, which make up the genus Oncorhynchus.
The six species of Pacific salmon (Oncorhynchus) are as follows: sockeye or sockeye (O. nerka), which extends from the northern Bering Sea to Japan and the Columbia River of the American Northwest; the coho or silver salmon (O. kisutch), which ranges from the Bering Sea to Japan and the Salinas River of Monterey Bay; chum or dog salmon (O. keta), which runs from the Mackenzie and Lena rivers in the southern Arctic south to Japan and the Rogue river; spring king salmon or chinook (O. tshawytscha) from the Yukon River to China and the Sacramento River; pink or humpback salmon (O. gorbuscha), from the Arctic to Japan and the Klamath River; and cherry salmon (O. masu), found in Japan. Atlantic salmon is native to rivers on both sides of the North Atlantic.
Adult Atlantic salmon averages approximately 10 pounds (4.5 kg) in weight, while real salmon averages approximately 23 pounds (10 kg), although individuals 50-80 pounds (22-36 kg) are not uncommon. Chum salmon average about 10–12 pounds (4.5–5.5 kg); coho salmon weighs around 7 to 10 pounds (3 to 4.5 kg); sockeye, about 4–7 pounds (2–3 kg); and pink salmon, 3–6 pounds (1.3–2.7 kg).
Pacific salmon live most of their lives in the ocean, but as adults they return to the stream where they were born to spawn. They use their olfactory senses (their sense of smell) to find their spawning grounds in their river of origin, and at least one species, sockeye salmon (Oncorhynchus nerka), may also feel differences in Earth’s magnetic field to navigate from return to its current of origin. from the open sea. The female digs a hole in the gravel of the stream in which she and a male spawn simultaneously, and then covers the eggs with gravel. Adult Pacific salmon die soon after spawning, but many Atlantic salmon return to the sea, and after one or two years in open water they can spawn again, some up to three or four times. Most salmon spawning occurs in late summer or fall, and the eggs generally hatch in late winter. Incubation rates are temperature dependent, from 60 to 200 days. After hatching, the salmon fry consume the yolk in the attached sack before going through the gravel to forage for food. Young pink salmon goes down almost immediately to the sea, while chum salmon leaves in a few weeks. Coho salmon stay a year in streams, while young king and Atlantic salmon can stay feeding in streams for one or three years or more. Young red salmon inhabit lakes for one to five years before migrating to the sea.
Sockeye salmon (Oncorhynchus nerka). The chemical characteristics of the domestic stream of a salmon are imprinted on the fish during their early development. As a result, once the fish has returned to its home stream after a period of two or three years at sea, it relies on smell to find its original spawning site. Sockeye salmon also uses magnetic fields to find its household currents.