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Bob Coey

Bob Coey. For SSU ENSP 421 students only – some slides/data have been modified from their original source. ONCHORHYNCHUS. All Pacific salmon are members of the genus Oncorhynchus, meaning "bent snout“ and have evolved for over 50,000 years.

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Bob Coey

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  1. Bob Coey • For SSU ENSP 421 students only – some slides/data have been modified from their original source

  2. ONCHORHYNCHUS • All Pacific salmon are members of the genus Oncorhynchus, meaning "bent snout“ and have evolved for over 50,000 years. • Range from southern California to northern Alaska and from Siberia southward to Hokkaido, Japan. • Adapted to gravel-bedded rivers and streams with clear, well-oxygenated waters that remain cold throughout the year (42-58o F). • Gravels must be relatively free from silts and fine sands to allow free flow of water and oxygen to eggs deposited in the inter-gravel spaces. • Life stage requirements vary by species (stream size, gravel size, flow and depth of water, and timing of return) • Watershed-specific variations in these characteristics have produced populations that are "fitted" to these environments and that differ in subtle ways from adjacent populations. • This local adaptation is a fundamental characteristic of Oncorhynchus

  3. Species Variation • Salmon hatch in freshwater from eggs laid in the gravel beds of rivers and streams (and in some cases along lake shorelines). • Except for steelhead and cutthroat, adults die after spawning a single time – most species are anadromous • Upon hatching, juveniles spend from hours to years in the freshwater environment before migrating to the sea to grow to adulthood. • Some species utilize estuaries to make the seawater transition • Oceanic migrations typically take them northward along the continental shelf as many as thousands of miles, often into the Gulf of Alaska and beyond. • On reaching maturity, they migrate from the ocean back to the rivers and streams of their birth to spawn. • Salmon using internal organs and olfactory clues as homing devices to return to their natal streams

  4. Return from sea varies by species • Coho 2 years • Chinook 2-5 years • Steelhead 0-3 years • Rainbow trout

  5. Salmon Inland Life Stages

  6. Observed Natural Returns and Returns Modeled by Ocean Conditions

  7. Observed Hatchery Survival and Survival Modeled with Ocean Conditions

  8. Pacific Ocean Pacific Ocean Juveniles Summer Pacific Ocean Smolts Fry Fall Spring Year 1 Winter Eggs Year 2 Jacks Year 3 Adults Coho Life Cycle

  9. Recent coho distribution over last 9 years or 3 life cycles ( purple) • Compared to historic distribution of coho (red) – presumed gone from >50% of native habitat • All 32 streams were sampled summer by DFG and NMFS staff • (3/32 presence found)

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