[env-trinity] Trinity River Spawn Survey Update for November 25 to 27

[Chamberlain, Charles]

Hi all,
Look for post of the complete report on our
website<http://www.fws.gov/arcata/fisheries/default.htm>early next
week.  Until then, here's the latest from our survey....

Our crews mapped the locations of 395 mainstem redds and 876 carcasses
November 25 to 27.  The river between Bucktail River Access and Round House
(on Sky Ranch Road) was not surveyed this week due to the Thanksgiving
holiday.

The redd numbers are starting to tick up in the upper river.  We expect
many of those to be Coho Salmon.  Here's what the cumulative graph looks
like so far.

[image: Inline image 1]

*Fun fact for the week...*
Did you know ….  Separation between Trinity River spring and fall Chinook
Salmon runs prior to the construction of Trinity and Lewiston dams was
maintained by their divergent life history strategies that separated the
two runs spatially at time of spawning.  Spring fish ascended the Trinity
during spring snowmelt periods and reached high into the basin above
Lewiston where they held through the summer in cold water pools.  Spring
Chinook Salmon entered the river with lots of high energy fat in their
tissues to sustain them through the summer months and to fuel them through
spawning.  Fall fish ascended during fall when lower water and relatively
limited energy reserves limited their upstream migration to lower elevation
spawning habitats.  As Chinook Salmon began to spawn in the fall, spring
and fall runs were separated spatially.  The upstream migration of both
runs is now limited by the dams and during spawning season they are mixed.
 While there is tendency for spring Chinook Salmon to spawn earlier than
fall Chinook Salmon, run timing for the two races overlaps considerably.
 Trinity River Hatchery closes the hatchery’s fish ladder for a period each
fall to maintain genetic separation of the hatchery spring and fall run
Chinook Salmon populations, but on the spawning riffles of the Trinity
River downstream of Lewiston Dam there is no mechanism to separate natural
spring and fall run Chinook Salmon by space (where they spawn) or time
(when they spawn).

Talk to y'all next week,
Charlie

Charles Chamberlain
Supervisory Fish Biologist
U.S. Fish and Wildlife Service
Arcata Fish & Wildlife Office
1655 Heindon Road
Arcata, CA 95521

Charles_Chamberlain at fws.gov
Phone: (707) 825-5110    Fax: (707) 822-8411
www.fws.gov/arcata/fisheries
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