[env-trinity] 2007 Lower Trinity River Juvenile Salmonid Outmigrant Monitoring In-Season Report

[Bill_Pinnix at fws.gov]

To Whom it May Concern:

                  Willow Creek Downstream Migrant Trap Site
                 2007 In-Season Trapping Update –May 14, 2007

   Synopsis: The 2007 Downstream Migrant trapping season at the Willow
   Creek Trap Site (river kilometer 34) is being conducted jointly by the
   USFWS Arcata Fish and Wildlife Office (AFWO) and the Yurok Tribal
   Fisheries Program (YTFP) on the mainstem Trinity River near Willow
   Creek, California.  The site utilizes multiple eight foot diameter
   rotary screw traps.  The season began March 5, 2007 with the
   installation of one trap.  A second trap was installed March 15, 2007,
   and a third trap was installed April 4th, 2007.  As the river continues
   to drop, salmonid catches are increasing rapidly.

   This summary includes data from March 6th, 2007 through May 6th, 2007
   and is presented as raw catch (see attached catch summary).  No
   expansions have been calculated at this time. Data entry is not complete
   for Julian Week 18, April 30th to May 6th.

   Raw daily catches of Chinook salmon (Oncorhynchus tshawytscha) have been
   captured each day sampling has occurred.  Most Chinook salmon captured
   during this time period have been young-of-the-year, and appear to be in
   good condition.  Weekly mean Fulton’s K values of young-of-the-year
   Chinook salmon are slightly higher than 1.0 with a possible slight
   increase in condition from Julian weeks 15 through 18.

   Raw daily catches of steelhead (Oncorhynchus mykiss) smolts (age 1) are
   increasing.  Steelhead young-of-the-year showed a small pulse in Julian
   Weeks 13-15.  All steelhead smolts captured appear to be in good
   condition with weekly mean Fulton’s K values slightly higher than 1.0.

   Raw daily catches of coho salmon (Oncorhynchus kisutch) are low,
   especially for natural smolts.  Weekly mean Fulton’s K value of natural
   coho salmon smolts are higher than 1.0, indicating good condition.  All
   coho salmon young-of-the-year appear to be in good condition with weekly
   mean Fulton’s K values near 1.0.  Coho salmon smolt catches, both
   natural and hatchery, in Julian Week 17 increased coincident with the
   increased water releases from Lewiston Dam.

   We have been catching good numbers of salmonids that were marked at the
   upstream Pear Tree Site, and this year may prove to have sufficient data
   to get precise calculations of migration rates between the two trap
   sites.

   If you have any questions regarding this summary, don't hesitate to
   contact Bill Pinnix at (707) 822-7201.

   (See attached file: WCT_CatchSummary_May_14_2007.pdf)

   Bill

William Pinnix
USFWS, AFWO
1655 Heindon Rd
Arcata, CA 95521
(707) 822-7201
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