In other words, this problem has been over-simplified by the media and others to one single root cause, namely the construction of hydroelectric dams on the Columbia river system. The Salmon controversy is an excellent example of arguments made largely on belief, instead of knowledge that is supported by the actual data . This is the raw salmon count data at Bonneville Dam. Evidence of quasi-cylical behavior is apparent. Low Salmon counts in recent years are not historically unprecedented.
Blue line represents growth of non-harvested fish in the Columbia River system.
Its getting warmer earlier in the season with time in the Columbia river. Graph shows harvesting by Tribal communities with protected fishing rights. The above documents and data strongly suggest that a significant reason for Columbia river salmon decline is due to increased harvests in Alaska and Canada. Its capacity of 1340 MW is vital to the PNW and hence large State funds have now been allocated for pollution reduction. Consumer ultimately pays for this.