[env-trinity] Mainstem Trinity River spawn survey update for December 15 to 19, 2014 - last one!

[Chamberlain, Charles]

Fans of the Trinity River,

The US Fish and Wildlife Service along with the Yurok Tribe, California
Department of Fish and Wildlife, US Forest Service, and Hoopa Valley Tribe
have just posted the last weekly update of our 2014 Trinity River mainstem
spawn survey.  It's available on the Arcata Fish and Wildlife Fisheries
webpage.
http://www.fws.gov/arcata/fisheries

High turbid water kept us off the River downstream of Hawkins Bar where we
would likely have seen many fresh Chinook Salmon redds.  Our survey was
limited to the River from Lewiston Dam to Round House.  Only 8 new redds
were mapped, all upstream of Rush Creek. The graph below is clipped from
our weekly report (limited to the river upstream of Cedar Flat).

[image: Inline image 1]



Do you feel it yet?  For the first time in a long time, today is longer
than yesterday.:)  I spent yesterday's winter solstice with visiting family
in Redwood National and State Parks viewing big Redwoods and Roosevelt Elk.
We tried to get to Gold Bluff Beach where you can often see elk right on
the beach, but Prairie Creek was flowing out of its banks and blocked the
access road.  That was great to see after such a long dry spell!


*Did you know*....  floods are extremely important for the health of a river
and the fish it supports?  Flooding increases food production for
salmonids, scours holes and redistributes gravels, knocks large trees into
the river where they become excellent fish habitat, loosens gravels that
can otherwise become locked with embedded finer grained sediment, deposits
fine material on floodplains where it contributes to successful riparian
establishment, initiates establishment of seedling trees, expands available
habitat to rearing salmonids, and much more.  In the absence of floods and
flow variability after construction of Trinity Dam, the Trinity River's
riparian corridor shrank to the narrow low water margin essentially
"locking" it in place.  Once confined between the narrow bands of riparian,
the formerly complex channel became greatly simplified.  One of the tools
available to the Trinity River Restoration Program (TRRP) to reinitiate
channel complexity is flow variability.  Delivering pre-dam sized floods is
not possible.  For example, the outlet capacity of Lewiston Dam is MUCH
lower than the nearly 24,000 cfs that would have been experienced at
Lewiston during recent rains on December 11 of this year (when flow at
Lewiston was 300 cfs).  Even so, flows are much more variable now than they
were between construction of the Dam in the early 60's and establishment of
the TRRP in 2000.  We may be able better mimic 'mini' floods in the future,
induce greater desirable variability, and make significant gains in habitat
availability by closer timing of releases with tributary input.



>From here out, the survey partners and I will be working to QA/QC this
year's data, estimate proportions of Chinook, Coho, hatchery, and natural
origin spawning by space and time from our carcass data, and generate a
summary report.  I'll announce that when it's available.


Thank you to Nick Van Vleet, Aaron David, and Katrina Wright for
contributing to the "Did you know" segments this year!

Thanks for tuning in this season. I hope you all enjoy a great Christmas
and 2015.  Happy holidays!
Charlie

Charles Chamberlain
Supervisory Fish Biologist
U.S. Fish and Wildlife Service
1655 Heindon Road, Arcata, CA 95521
http://www.fws.gov/arcata/fisheries
(707) 825-5110
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