News from the Front #88:

Ocean Tracking Data Suggest No Harm to Fish Populations from Snake Dams and Large Benefits to Smolt Transportation

On January 11, 2007, Dr. David Welch, a Canadian researcher working under contract to BPA, released the results of tracking several hundred hatchery juvenile spring chinook released above and below the four Snake River Dams.  One batch of fish was released 76 km up the Yakima River using stock from the Cle Elum Supplementation and Research Facility.  Another group was released into a tributary of the Snake River (near Kooskia National Fish Hatchery) using stock from Dworshak National Fish Hatchery.  Other groups consisted of controls and a transport group trucked to Lower Granite Dam and then barged with the other transported fish.

The fish were then tracked out into the ocean using the Pacific Ocean Shelf Tracking Array, with stations in Willapa Bay, Washington, across the Strait of Juan de Fuca, and offshore of NW Vancouver Island.  These tracking stations provide the first and only ability directly to measure near-ocean survival of juvenile salmon. 

The results were simple and elegant.  Of the roughly 400 fish released up the Yakima River, about 80 were detected in Willapa Bay .  Of the roughly 400 fish released up the Snake River , about 80 were detected in Willapa Bay .  Since the Snake River fish had to migrate through four additional dams (and considerably farther downstream), this result is yet another nail in the coffin of the hypothesis that migration through four additional dams imposes significant incremental mortality on juvenile migrants. 

Of the roughly 200 fish transported down the river in barges and released below Bonneville Dam, roughly 80 were detected at Willapa Bay .  This was double the detected percentage of the river-migrating fish, and a few detections at the stations north of Willapa Bay tend to show that the doubling benefits persisted.  At least when transportation benefits are taken into account—and not destroyed by Judge Redden―one cannot rule out the hypothesis that the Snake River dams provide survival advantages for Snake River stocks as compared to migrating in an undammed river.

No study is perfect.  The ocean tracking stations were not particularly durable, so that a consistent set of detectors was not maintained through the year (one detector in the Columbia River was even snagged and removed by a sportsfisher).  Only the largest half of total fish population could hold tags, and populations reached the detectors at different times.  The Snake River fish were also a different genetic stock than the Yakima fish, an issue that confounds all upriver/downriver determinations from different basins, but Yakima fish have enjoyed strikingly higher adult returns recently, a fact dam opponents have blamed on Snake River dam passage for the upstream stocks.

This study provides good evidence that whatever advantage the Yakima fish have been enjoying, it isn’t something that has been happening in their near-ocean life stage.  Dam opponents have speculated that the Snake River fish suffer delayed mortality from dam passage (the “I was abused as a smolt” theory), but as Dr. Welch confirms that this data (at least north to Vancouver Island) does not support the concept of delayed mortality; he concludes that “poor Snake River survival occurs somewhere later in the ocean life history and that differential effects of the ocean have been confounded with the operation of the hydrosystem”.

My personal hypothesis remains that the Snake River stocks migrate further west and are disproportionately picked off by Far Eastern fishermen, who continue to run huge driftnets ostensibly targeted at squid.  Every once in a while when the Coast Guard actually looks for illegal salmon harvest by Far Eastern interests, they find boatloads of illegally caught salmon—and they don’t even look very far out into the ocean.  All over the world, excessive ocean harvest is destroying fishable stocks, but here in the Pacific Northwest, the fishermen continue to fund environmentalists to blame the dams, and everyone believes them.

Unfortunately, scientific data has less and less relevance in decisionmaking concerning Columbia River dam operations.  The Regional Administrator of the National Marine Fisheries Service declares both publicly and privately that the river is now run by Judge Redden, and all that matters to him is that NMFS reach agreements with the fish advocates Judge Redden  supports―even if the agencies have to kill fish to do it.  Hence yet another year of suboptimal transportation levels, coupled with millions of dollars in bribes* promised to Native American Tribes (2.92 Mb Adobe Acrobat file), all to avoid having fish advocates ask for even more idiotic relief from Judge Redden.  But at least data such as Dr. Welch's will be there when and if we ever do decide to make decisions based on data, rather than anti-technological superstition.

© James Buchal, January 22, 2007

*I use the word "bribes" to refer to promised Federal funding for various Tribal programs that did not pass muster under normal and lawful budget review processes, such as subsidizing Tribal law enforcement and fostering populations of freshwater mussels and salmon predators.  

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