A federal report released in March has outlined what caused the collapse of the Sacramento River Fall Chinook salmon stocks. In a nutshell, it’s pretty much everything I said in back in an article I wrote in 2008 (to see it click HERE).
Here are some interesting tidbits I found in the report:
•”A broad body of evidence suggests that anomalous conditions in the coastal ocean in 2005 and 2006 resulted in unusually poor survival of the 2004 and 2005 broods of Sacramento River Fall Chinook (SRFC). Both broods entered the ocean during periods of weak upwelling, warm sea surface temperatures, and low densities of prey items. Pelagic seabirds in this region with diets similar to juvenile Chinook salmon also experienced very poor reproduction in these
years.”
•”The long-standing and ongoing degradation of freshwater and estuarine habitats and the subsequent heavy reliance on hatchery production were also likely contributors to the collapse of the stock.”
• “In addition, the cessation of net-pen acclimatization in the estuary in 2006 may have contributed to the especially poor estuarine and marine survival of the 2005 brood.”
•”Freshwater withdrawals (including pumping of water from the Sacramento-San Joaquin Delta), unusual hatchery events, pollution, elimination of net-pen acclimatization facilities and large-scale bridge construction during the smolt outmigration along with many other possibilities have been suggested as prime candidates causing the poor escapement.”
•”Low escapement has also been documented for coastal coho salmon during this same time frame. For California, coho salmon escapement in 2007 averaged 27% of parent stock abundance in 2004.”
And how is it looking for the fall of 2009, when many of the fish hatched in 2006 are scheduled to return?
•”The preliminary estimate of SRFC jack escapement was 4,060, double that of the 2005 brood, but still the second lowest on record and a level that predicts an adult escapement in 2009 at the low end of the escapement goal absent any fishing in 2009.”
To see how far we’ve fallen, check this out:
• “Maximum annual stock size (including harvest) of Central Valley Chinook salmon before the twentieth century has been estimated conservatively at 1-2 million spawners.”
So, what can be done?
It looks like we pray for good upwelling in the ocean, drastically reform our hatchery practices, restore rearing habitat in the Delta system and keep cold water flowing down the rivers to name a few.
To see the entire report: Salmon Decline Report.
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