Biological Opinions - Bureau of Reclamation

prohibited in California river fisheries. In order to comply with the SONCC coho salmon ESU
conservation objective, projected incidental mortality rates on Rogue/Klamath River hatchery
coho salmon stocks are calculated during the preseason planning process using the coho salmon
FRAM (Kope 2005). Season options are then crafted that satisfy the 13 percent maximum ocean
exploitation rate. In recent years, these rates have been well below 13 percent with 5 of the last 8
years at or below 6 percent and no year exceeding 9.6 percent. Preliminary post-season
estimates of ocean incidental mortality rates for 2010 and 2011 are 2.2 and 3.8 percent,
respectively (PFMC 2011, 2012). Due to the predicted low abundance of Sacramento River
Basin fall-run Chinook salmon, severe ocean salmon fishing closures were adopted in 2008.
Tribal and other harvest effects are expected to continue.
Because incidental ocean exploitation and tribal harvest rates vary, the effects of salmon
harvesting to the VSP parameters of the Klamath populations may vary from neutral to negative.
The main effect to the VSP parameters is a reduction in the population abundance level.
However, by selecting for certain size classes, runs, or certain ages of individuals, harvesting can
also impact genetic diversity. By reducing the number of adults returning to a stream or river,
fish harvesting can in turn reduce the amount of marine derived nutrients, which can impact
summer and winter juvenile rearing areas by limiting the amount of food available to juveniles as
invertebrate production may suffer.
12.3.3.3 Pinniped Predation
Pinniped predation on adult salmon can significantly affect escapement numbers within the
Klamath River basin. Hillemeier (1999) assessed pinniped predation rates within the Klamath
River estuary during August, September, and October 1997, and estimated that a total of 223
adult coho salmon were consumed by seals and sea-lions during the entire study period. Fall-run
Chinook salmon were the main fish consumed (an estimated 8,809 during the entire study
period), which may be primarily due to the fall-run Chinook salmon migration peaking during
the study period (the peak of the coho salmon run is typically October through mid-November).
Hillemeier (1999) cautioned that the predation results may represent unnaturally high predation
rates, since ocean productivity was comparatively poor during the El Niño year of 1997. The
Marine Mammal Protection Act of 1972, as amended, protected seals and sea lions from human
harvest or take, and as a result, populations are now likely at historical highs (Low 1991).
Similarly to harvesting, reductions in the amount of marine derived nutrients in a stream can
result from predation, which reduces the amount of food available to winter and summer rearing
juveniles.
12.3.3.4 Recent activities that have permitted or exempted take in the action area
Some of the activities listed above have either permitted or exempted take of coho salmon in the
action area. A summary of projects that have current exemption or permit to take SONCC ESU
coho salmon in the action area is provided below (Table 12.4). Note that the effects of the
Klamath Project Operations and PacifiCorp HCP were discussed earlier, and that the effects of
the Klamath Project as described in the 2010 BiOp (NMFS 2010a) will be replaced by this BiOp.
The other activities where NMFS permitted or exempted take in the action area are associated
with habitat restoration and research/monitoring. Habitat restoration, research, and monitoring
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