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Hello,
My experience with this is limited. I participated in a couple of sockeye spawner surveys in southeast Alaska, in the primary tributary to McDonald Lake. There were very few redds in the stream. The substrate was mostly fist sized pieces of granite. The sockeye would spawn and the eggs would drop down into the spaces between the rocks.
Gary
Gary Sprague
206.233-5108
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-----Original Message-----
From: Scientific forum on fish and fisheries [mailto:[log in to unmask]] On Behalf Of [log in to unmask]
Sent: Thursday, February 11, 2010 6:36 AM
To: [log in to unmask]
Subject: Redd counts and construction
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In the recently published AFS book _Standard Methods for Sampling North
American Freshwater Fishes_ there is the following statement in one section
re: the use of redd counts (p. 122):
"In some cases, eggs could be broadcast directly into the substrate with no
redd construction. To our knowledge, this behavior is not well documented
for stream-living salmons and trouts, but field observations (e.g., lack of
observable redds in streams with high juvenile recruitment) indicate that
this is a distinct possibility."
The field observations mentioned in this quote are consistent with some of
my (albeit limited) observations (or interpretations) in some local streams.
Does anyone have a reference for this behavior or, in the lack of that,
does anyone have an observation or opinion about this quote.
Thanks in advance for any help or discussion.
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