[env-trinity] Trinity River Spawn Survey Update for December 16 to 19

Chamberlain, Charles charles_chamberlain at fws.gov
Fri Dec 20 11:05:28 PST 2013


Howdy all,
Fieldwork for our Fall 2013 Trinity River Spawning Survey wrapped up
yesterday 12/19, and our final in-season report is now posted at our
website http://www.fws.gov/arcata/fisheries

This week our crews mapped the locations of 291 redds and 1,260 carcasses.

Official escapement estimates for the year will come out sometime in late
January or February.  Suffice it to say, it was not a fabulous year for
numbers of spawning salmon in the Trinity River.  The graph below clipped
from our weekly report shows our preliminary cumulative redd count for the
river from Lewiston Dam to Cedar Flat.  We just barely snuck back 'into the
blue' with this week's additional redds.

[image: Inline image 1]

Chinook Salmon are still actively spawning in the river downstream of
Hawkins Bar (not included in the graph above).  Those lower river fish
exhibit a later run timing.  Most years we're precluded from surveying down
there this late in the season due to storms and turbid water.

*Fun fact for the week...*
Did you know …. Salmon are programmed to return to their place of birth to
spawn.  Of course you knew that already!  The mechanisms of their
navigation however, are not fully understood.  In the wide open ocean it’s
thought that a salmon senses Earth’s magnetic fields and homes in on
magnetic intensity and inclination matching those imprinted in its memory
bank when it migrated seaward as a smolt.  Once close to its natal river,
it’s believed that excellent olfactory senses largely take over navigation
duties.
Putman et al 2013<http://www.sciencedirect.com/science/article/pii/S0960982213000031>



Thank you all for tuning in this season!  Over the next several weeks we'll
be hard at work scrutinizing, analyzing, and summarizing our data, and will
post link to a final report when it's available. Until then, have a merry
Christmas/Happy Holidays.  I'm asking Santa for rain!

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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