Carbaryl, Carbofuran, and Methomyl - National Marine Fisheries ...

improvements in 2000, with upward trends continuing in 2001 and 2002. The recent
five-year mean abundance is variable among populations in the species, ranging from one
fish to nearly 4,500 fish. Hood Canal summer-run chum salmon are the focus of an
extensive rebuilding program developed and implemented since 1992 by the state and
tribal co-managers. Two populations (the combined Quilcene and Union River
populations) are above the conservation thresholds established by the rebuilding plan.
However, most populations remain depressed. Estimates of the fraction of naturally
spawning hatchery fish exceed 60% for some populations. This indicates that
reintroduction programs are supplementing the numbers of total fish spawning naturally
in streams. Long-term trends in productivity are above replacement for only the Quilcene
and Union River populations. Buoyed by recent increases, seven populations are
exhibiting short-term productivity trends above replacement.
Of an estimated 16 historical populations in the ESU, seven populations are believed to
have been extirpated or nearly extirpated. Most of these extirpations have occurred in
populations on the eastern side of Hood Canal, generating additional concern for ESU
spatial structure. The widespread loss of estuary and lower floodplain habitat was noted
by the BRT as a continuing threat to ESU spatial structure and connectivity. There is
some concern that the Quilcene hatchery stock is exhibiting high rates of straying, and
may represent a risk to historical population structure and diversity. However, with the
extirpation of many local populations, much of this historical structure has been lost, and
the use of Quilcene hatchery fish may represent one of a few remaining options for Hood
Canal summer-run Chum salmon conservation.
Of the eight programs releasing summer chum salmon that are considered to be part of
this ESU, six of the programs are supplementation programs implemented to preserve
and increase the abundance of native populations in their natal watersheds. NMFS’
assessment of the effects of artificial propagation on ESU extinction risk concluded that
these hatchery programs collectively do not substantially reduce the extinction risk of the
ESU. The hatchery programs are reducing risks to ESU abundance by increasing total
ESU abundance as well as the number of naturally spawning summer-run chum salmon.
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