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

[Bill_Pinnix at fws.gov]

Here's the copy with the attachment

                  Willow Creek Downstream Migrant Trap Site
                2007 In-Season Trapping Update –June 20, 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 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.

   This summary includes data from March 6th, 2007 through June 8th, 2007
   and is presented as raw catch.  No expansions have been calculated at
   this time. Data entry is not complete for Julian Weeks 21 through 23,
   May 21st to June 10th.  Heavy debris load from the increased dam
   releases created problems for the rotary screw traps during Julian Weeks
   (JW) 18–20, and resulted in less than 21 trap days per week (7 days per
   week x 3 traps= 21 trap days per week).  See attached catch summary for
   details of this narrative.

   Raw daily catches of Chinook salmon (Oncorhynchus tshawytscha) have been
   captured each day sampling has occurred and most have been
   young-of-the-year (YOY).  Weekly mean Fulton’s K values of YOY Chinook
   salmon are slightly higher than 1.0 with a possible increase in
   condition from JW 15-22 compared to JW 10-14.  Chinook salmon catches of
   natural fish peaked JW 19 and tapered off until the arrival of hatchery
   Chinook salmon in JW 23.

   Raw daily catches of steelhead (Oncorhynchus mykiss) smolts (age 1+)
   peaked coincident with the increased flow in JW 17 and have tapered off
   with a few smaller peaks in catch.  No age 2 steelhead occur on the
   catch summary because steelhead scales have not been aged this year;
   once aging is complete some age1 steelhead will be moved to the age 2
   column.  Steelhead smolts captured JW 10-19 had weekly mean Fulton’s K
   values slightly higher than 1.0; values dropped below 1.0 in JW 20-23
   possibly indicating that the smolting process is occurring.  Steelhead
   YOY catches showed a small pulse in JW 13-15 and appear to be increasing
   in the past few weeks.  Normal peaks in YOY steelhead catch occur in
   mid-June to early July.

   Raw daily catches of coho salmon (Oncorhynchus kisutch) are low compared
   to the past 5 years, especially for natural smolts.  Weekly mean
   Fulton’s K value of natural coho salmon smolts were higher than 1.0 in
   JW 11-18, but have decreased below 1.0 in JW 19-23; possibly indicating
   that the smolting process is occurring.  Coho salmon smolt catches, both
   natural and hatchery, in JW 17 increased coincident with the increased
   water releases from Lewiston Dam.

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

   (See attached file: WCT_CatchSummary_June_19_2007.pdf)

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