I am involved with the Yakima/Klickitat Fisheries Project, an
experimental program testing whether natural production of anadromous
salmonids can be increased by "supplementation" -- by acclimated
outplants of "naturalistically-reared" hatchery smolts. At the present
time, the target species is spring chinook salmon in the upper Yakima
River (Washington state). My question: what is the optimal method of
determining whether natural production of a supplemented population
approaches or exceeds carrying capacity?
I am convinced that the proper approach is NOT to try to estimate
"the" carrying capacity of the basin for spring chinook. The Yakima is
subject to too many variable and large-scale abiotic impacts for this to
be fruitful. Rather, I would like to compile a list of the effects one
would expect to see in a natural population experiencing high
intensity density-dependent impacts. My intention is to design a
monitoring program to track such impacts and their correlation with
natural smolt (or parr) production.
Some of the candidate impacts I am considering include: reduced
length/weight/condition factor of parr and smolts; "inappropriately"
expanded spawning and rearing distributions; depressed egg-to-smolt
survival; a shift in dominant life history type; later and/or more
protracted outmigration timing; and perhaps the appearance of significant
numbers of age-2 smolts. Are all of these appropriate? Which important
impacts am I omitting?
Any suggestions would be very much appreciated. My E-mail
address is [log in to unmask], and my phone number is 509-966-5156.
Thanks for your consideration.