[env-trinity] CalTrout on Trinity

[Seth Naman]

Bill,

I would use caution in using the results of my thesis to explain changes in
salmonid populations in the Trinity River. It would take a rigorous
multi-year analysis to be able to distinguish the mortality from predation
by hatchery steelhead from the many other sources of mortality that salmon
experience throughout their life and to test if the predation mortality was
compensatory or additive.  

I highly doubt if hatchery steelhead, residualized or not, are thriving on
hatchery coho salmon because of the energetic costs associated with prey
handling and capture (see the attached paper). It's too costly to chase a
hatchery coho salmon smolt and the hatchery steelhead would much prefer
sipping fry. Though we did find one or two residualized hatchery steelhead
that were capable of making the benefits of chasing hatchery coho salmon
smolts outweigh the costs (see the attached picture), but these were rare
cases.  

Seth

-----Original Message-----
From: env-trinity-bounces at velocipede.dcn.davis.ca.us
[mailto:env-trinity-bounces at velocipede.dcn.davis.ca.us] On Behalf Of Kier
Associates
Sent: Thursday, December 08, 2011 1:23 PM
To: 'Tom Stokely'; env-trinity at velocipede.dcn.davis.ca.us
Subject: Re: [env-trinity] CalTrout on Trinity

Darren doesn't mention Seth Naman's HSU MS thesis/ research ,  that which
(if memory serves) suggested that steelhead are residualizing and thriving
on hatchery coho. 

Wouldn't that help explain 'steelhead up; coho down; chinook no progress'?

Bill

Kier Associates, Fisheries and Watershed Professionals P.O Box 915 Blue
Lake, CA 95525
(707) 668-1822
Mobile: 707.498.7847
www.kierassociates.net
GSA Contractor GS10F0124U


-----Original Message-----
From: env-trinity-bounces at velocipede.dcn.davis.ca.us
[mailto:env-trinity-bounces at velocipede.dcn.davis.ca.us] On Behalf Of Tom
Stokely
Sent: Thursday, December 08, 2011 10:41 AM
To: env-trinity at velocipede.dcn.davis.ca.us
Subject: [env-trinity] CalTrout on Trinity

See
http://caltrout.org/2011/12/are-steelhead-salmon-returning-to-the-trinity-ri
ver/?utm_source=California+Trout+List&utm_campaign=210827c6c5-12_5_2011&utm_
medium=email 

Tom Stokely
Water Policy Analyst/Media Contact
California Water Impact Network
V/FAX 530-926-9727
Cell 530-524-0315
tstokely at att.net
http://www.c-win.org

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