Biological Opinions - Bureau of Reclamation

likely to result in a level of habitat reduction where coho salmon fry and juveniles in the Upper
Klamath, Middle Klamath, Shasta, and Scott river populations will have reduced life history
diversity.
12.6.2.4 Spatial Structure
NMFS does not expect the proposed action will reduce the spatial structure of coho salmon
because the proposed action is not expected to create any physical, biological, or chemical
barriers. As discussed in the Effects to Individuals section (i.e., sections 12.4.1.2.1 and
12.4.1.2.4.3), NMFS concurs with Reclamation’s determination that the proposed action is not
likely to adversely affect adult coho salmon migration in the mainstem Klamath River and does
not expect the proposed action will have an adverse effect on coho salmon juvenile migration
corridors into tributaries. In addition, the proposed habitat restoration is likely to increase coho
salmon spatial structure in the action area when barriers (e.g., improperly sized culverts) are
removed.
12.6.3 Summary
Of all the adverse effects of the proposed action, NMFS believes that the disease risk from C.
shasta is the most significant to coho salmon. NMFS concludes that the proposed action will
result in disease risks to coho salmon that are lower than under observed POR conditions yet
higher than under natural flow conditions. By lowering disease risks in a direction toward those
under natural flow conditions, NMFS believes that coho salmon abundance and productivity will
likely improve over the next ten years for the Upper Klamath, Middle Klamath, Shasta, and Scott
river populations. NMFS believes the proposed action is not likely to result in a level of habitat
reduction where coho salmon fry and juveniles in the Upper Klamath, Middle Klamath, Shasta,
and Scott river populations will have reduced life history diversity. Finally, NMFS does not
expect the proposed action will reduce the spatial structure of coho salmon in the action area
because the proposed action is not expected to create any physical, biological, or chemical
barriers.
While factoring the environmental baseline conditions of the action area, the status of the
Klamath River coho salmon populations and the SONCC coho salmon ESU, and the cumulative
effects, NMFS believes the proposed action is not likely to increase the extinction risk of the
Upper Klamath, Shasta, Scott, Salmon, and Middle Klamath river populations. Therefore, the
proposed action is not likely to increase the extinction risk of the Interior Klamath Diversity
Stratum or the SONCC coho salmon ESU.
12.7 Conclusion
After considering the best available scientific and commercial information, the current status of
the SONCC coho salmon ESU, the environmental baseline for the action area, the effects of the
proposed action, and cumulative effects in the action area, it is NMFS’ biological opinion that
the action, as proposed, is not likely to jeopardize the continued existence of the SONCC coho
salmon ESU.
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