SALMON

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SALMON
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BASIC SALMON FACTS TERMS

• Are anadromous, meaning that they are hatched and
  reared in freshwater, but spend part of life in
  sea before returning to fresh water to spawn.
  All native Pacific salmon die after spawning,
  some North Atlantic salmon do not.
• Genetics all trout and salmon can be traced to
  a time when they shared a common gene pool.
  Pacific trout and salmon are genetically distinct
  from Atlantic salmon.

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• While some lake trout can live to be 60 years
  old, the lifecycle of salmon rarely extends more
  than 6 yrs.

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SPAWNING BEHAVIOR

• Rainbow and cutthroat trout generally spawn
  earlier in the milder climates of more southerly
  or coastal areas
• The timing of Pacific salmon spawning varies
  greatly

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Why do salmon and anadromous trout migrate?

• The benefits outweigh the costs they take
  advantage of the abundant food of the ocean.
  Because of this, they return larger than most of
  the local competition. This allows them to
  dominate the best spawning locations, and lay
  many large eggs with yolk that sustains their
  young for weeks.

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SPAWNING BEHAVIOR (cont)

• homing instinct aided by celestial navigation and
  detection of earths magnetic fields
• Once in the home river, the olfactory sense is
  used

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Growth

• Determined by interactions between heredity and
  physical environment constraints
• Salmon and trout can grow throughout their
  lifetime.
• Are cold blooded, and rates of growth and
  longevity are greatly influenced by water
  temperature. Metabolic rate increases with
  higher water temperature, so more food must be
  consumed.
• Oxygen levels, salinity, competition, and food
  availability also impact growth

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What they eat

• Are generalists and opportunists
• In fresh water, most rely heavily on aquatic
  insects, but feeding patterns can vary greatly by
  season
• Crustaceans such as shrimp, crayfishes can also
  be significant

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Life Cycle
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Life Cycle

• Reproduce in cold, flowing water by creating
  excavations in gravel called redds
• Have relatively large eggs
• Leave birth stream, go downriver
• Many stay in coastal estuaries for weeks before
  seaward migration
• Ocean life lasts 1-5 years, where large size
  attained
• Return to home stream done without feeding