From the Edge: Science to Support Restoration of Pacific Salmon Page: 29
57 p. : col. ill., col. mapsView a full description of this text.
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1960 1965 1970 1975 1980 1985 1990
Figure 16. Numbers of hatchery coho salmon smolts released and estimated
abundance of adult salmon produced the following year in the Oregon Production
Area. Increasing smelt production is no longer increasing adult returns.
The Importance of Natural Variation:
Environmental variability and genetic diversity
may be the keys to salmon suLr'ival. Natural vari-
abhility cntributes to the diversity of habitat types Impacts of. A
necessary for mtanltaiin c cnetic variabiliity. and Artificially p
the role and value of variabilit must be recog replaced natu
rlized. One-size-fits-all solutions are generally muclh of the
inappropriate; planning and implementation should to which hatc
he tailored to local conditions. D)ecadal cycles of to or conitribr
ocean productivity have the potential to mask dlucing popul
changes in the survival of salmon during fresh wa- There is an a
ter phases ofi their life cycle, leading to erroneous tion on the ir
interpretation of the performance of restoration with wild poi
efforts and increased losses of some stocks. duced fish or
Chances in marine survival need to be tracked genetic alter
closely and findings incorporated into management disease.
planning. Protection of freshwater hIabitats is par-
ticularly important during periods of' low produc- Hydroelectr
tivity in the ocean. Salmon harvest rates should There is gent
take changes in marine survival into account. opilenit ill thi
has adverse.1
Habitat Factors: Human activities (forestry. agri there is still
culture and grLaiing. hyvdro)power. and urban and it mechLanisms
industrial dcvelopment) have degraded, fragmlent- Tl'here are nlia
ed. and cdiscon nected riverine and adjacent riparian river dischar,
habitats. Ma~or long-term intervention will be 'ival, includi
required to restore the spatial and temporal diversi- tarii sport:atior
ty of these habitats and to reconnect habitat types and operation- I !r i Ih I I
- P ciic Salmon, and their Ecosystems 19629
important f)or continuity in the life
cycle es ol salrnmon. iinclurdini Spavi-
in anld rearing sites arid liirato(ry
corridors. Riparian features and
processes. large woody debris
recruiti-ent. water quality natural
sediime station rates, floods and
other natural disturbance rce imres,
adequate stream tlovs. anld Uiplarind
(wlterslhed) processes are all key
element s in restoring g habitat.
Some ecosystem processes need
research more than others to estab-
lish hov i much rermediation will be
sufficient. Core or reserve areas
that currently maintain strong pop-
ilatio(ns of salmorn are of particular
ecological importance and should
be protected land reconnected w ith
one another. ITlabitat rehabilitation
will require action on both public
and private lands, and arongE all
types of land uses.
artificial Propagation Programs:
ropagated salm on have largely
rally spaxnirg plopulations .over
Coluimbia River basin. but the degree
:her program s have been detrimental
lted to the sur vival of naturally repro-
ations is not c learly understood.
rent need for f Iindarrmental in forrmLa-
teractioIs of hatcher..-produced fish
pulratioris. Effects of hate lery-pro-
i wild stocks potentially. include
ition. competition, predation, and
ic Development and Operations:
eral agreement that hvdropo.er devel-
e Columbia and Snake River basins
y affected salmonid populations. but
iuchrl disagreermenrit about the specific
that cause these adverse effects.
iy resolved issues dealing withl
e anrid its relationship to salmon siur-
ng the efficacy of floxx augmentation,.
an, reserx voir drawdo ri i and structural
nal improvements at mainstei dams.
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National Science and Technology Council (U.S.). Committee on Environment and Natural Resources. From the Edge: Science to Support Restoration of Pacific Salmon, text, November 2000; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc25982/m1/38/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; .