It seems like a sick joke to call something "best available data" when the study barely looks at terminal fisheries and the predation that happens. Even sicker that its 20 year old data- they actually have studies published on the wdfw website that show the significance of pinnpiped predation on outmigrating steelhead smolt.

https://www.int-res.com/articles/meps_oa/m543p021.pdf

"A major shift in the Puget Sound food web
occurred in the early 1990s (Harvey et al. 2012).
Although the specific causes are un known, several
previously abundant demersal species (Pacific cod
Gadus macrocephalus, hake Merluccius productus,
rockfishes Sebastes spp.) and some pelagic (Pacific
herring Clupea pallasi) stocks suffered steep
declines (Gustafson et al. 2000, Drake et al. 2010,
Landis & Bryant 2010). Concurrently, marine survival rates of larger-bodied salmonid smolts (steelhead and coho salmon) also declined (Scott & Gill
2008, Zimmerman et al. 2015). These changes
occurred at the same time that harbor seal numbers
increased following implementation of the federal
protections for marine mammals (Jeffries et al.
2003)."