Key themes in Pacific salmon biology

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Key themes in Pacific salmon biology

• Anadromy breed in fresh water, migrate to sea to
  feed, and return to fresh water. Consequences
  large size and high density. Exception
  non-anadromy.
• Homing return to natal site to breed.
  Consequence evolution of discrete populations,
  requiring complex management. Exception
  straying.
• Semelparity death after first reproduction.
  Consequences highly productive populations
  return of marine-derived nutrients.
  Exception iteroparity.

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Defining life history traits for Pacific salmon

• Fall, rather than spring, spawning
• Large eggs, producing large fry
• Egg burial, an unusual form of parental care
• Juveniles use diverse freshwater habitats
• Estuarine use patterns seem to depend on size
• Coastal or offshore epipelagic zone at sea
• Growth rates at sea are rapid
• Populations are highly productive

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Chum salmon
Atsushi Sakurai
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Steven Schroder
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Manu Esteve
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Steven Schroder
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Eyed eggs
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Alevin hatching
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Male
Chum salmon, Oncorhynchus keta
Female
W. Palsson
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Ernest Keeley
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Coho salmon, Oncorhynchus kisutch
Deep body, large parr marks, hooked anal fin,
dorsal and anal fins have white and black margins
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Coho salmon fry
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Coho salmon fry in a stream, note prominent fin
margins
J. Rhodes
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Coho salmon
smolt
parr
A. Dittman
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Coho salmon, Oncorhynchus kisutch
W. Palsson
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Mature male coho salmon
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Hypothetical survival schedules for chum and
coho salmon
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Carrying capacity for Big Beef Creek coho salmon
D. Seiler, WDFW
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Big Beef Creek coho salmon production
D. Seiler, WDFW
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Pink salmon, Oncorhynchus gorbuscha
No parr marks, ready to enter seawater
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Sockeye salmon, Oncorhynchus nerka
Small, streamlined, parr marks uneven in size,
some equal above and below lateral line
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Sockeye salmon, Oncorhynchus nerka
Age 1 smolt
Age 2 smolt
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Male sockeye salmon
Female
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Parr marks wider than spaces, clear window in
adipose fin, dorsal fin has dark leading edge and
white tip, anal fin not hooked and leading edge
is shorter than the base
Chinook salmon, Oncorhynchus tshawytscha
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Kitsumkalum River chinook salmon
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Pacific trout vs. salmon

• Trout (rainbow and cuttthroat) spawn in the
  spring rather than the fall
• Trout are iteroparous rather than semelparous
  like the salmon
• Trout are often not anadromous. They may reside
  in small streams, migrate to rivers, lakes or
  saltwater for rearing.

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Rainbow/steelhead trout, Oncorhynchus mykiss
Note the spots on the dorsal fin, body, and tail,
and short jaw
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Coastal cutthroat trout, Oncorhynchus clarki
M. Erickson
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