Chinook salmon successful at guarding their redds. Chinook eggs hatch, 90 to 150 days after deposition, depending upon water temperature. Egg deposits are timed to ensure the young salmon fry emerge during an appropriate season for survival and growth. Fry and parr (young fish) usually stay in fresh water 12 to 18 months before traveling downstream to estuaries, where they remain as smolts for several months. Some Chinooks return to the fresh water one or two years earlier than their counterparts, and are referred to as "jack" salmon. "Jack" salmon are typically less than long, but are sexually mature and return at
Salmon run its birth, spawning, and then dying. Semelparous animals spawn once only in their lifetime. Semelparity is sometimes called "big bang" reproduction, since the single reproductive event of semelparous organisms is usually large and fatal to the spawners. Most Atlantic salmon also die after spawning, but not all. About 5 to 10%, mostly female, return to the ocean where they can recover and spawn again. In the Pacific Northwest and Alaska, salmon is a keystone species, supporting wildlife from birds to bears and otters. The bodies of salmon represent a transfer of nutrients from the ocean, rich in nitrogen, sulfur, carbon