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
The Salmon of Doubt six is a better kind of number." The book as published is divided into two main sections: "Life, the Universe and Everything", which utilizes fiction, essays and interviews with Adams, and "The Salmon of Doubt", which presents the most complete version of the novel as Adams left it. The first section is then subdivided into three: "Life" touches upon Adams' own life, "The Universe" covers Adams' views of reality and "Everything", which is more wide open and includes the original version of the Hitchhiker's short story "Young Zaphod Plays It Safe". The UK edition includes an introduction by Stephen Fry,