[env-trinity] Trinity River Spawn Survey Update for December 2 to 5

Chamberlain, Charles charles_chamberlain at fws.gov
Sat Dec 7 12:30:59 PST 2013


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 411 mainstem redds and 1,104 carcasses
December 2 to 5.  The river between Steelbridge River Access and Douglas
City Campground was not surveyed this week due to hazardous roads.

About 70% of the newly encountered carcasses in the upper two reaches
(Lewiston Dam to Bucktail River Access) are Coho Salmon, so the fall
Chinook Salmon spawning activity in those reaches is nearing an end for the
season.  Chinook Salmon spawning activity in the lower river downstream of
Hawkins Bar is still going strong.  Here's what the cumulative graph looks
like so far.
[image: Inline image 1]

*Fun fact for the week...*
Did you know ….  The adipose
fin<http://www.thefisheriesblog.com/2013/05/the-adipose-fin-old-mysteries-with-new.html>on
salmonids is the small nub-like fin of tissue on the top of the fish
between its primary dorsal fin and tail.  It was once believed that the fin
was composed of fatty tissue, thus the name “adipose” which comes from the
Latin *adiposus *meaning “fat”.  Clipping this fin off of juvenile hatchery
salmonids is often used to differentiate them from their natural fish, or
to identify salmon that have been tagged with a
coded-wire-tag<http://www.fws.gov/wafwo/pdf/mmbrochure.pdf>.
  The evolutionary origin of the fin is not well understood.  It’s long
been believed to be remnant of a formerly purposed fin somewhere back in
the evolutionary development of salmonids.  There is new thought however,
that the adipose fin may actually have a contemporary purpose based on
recent findings that the fin contains extensive nervous tissue and numerous
cilia (tiny hair-like sensory structures).  Thoughts are that the fin may
serve as a flow sensor and contribute to the fish’s swimming efficiency as
it navigates turbulent waters.
Buckland-Nicks et al.
2011<http://rspb.royalsocietypublishing.org/content/early/2011/07/06/rspb.2011.1009.short?rss=1>
.

Until 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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