Darrell Ticehurst/Fisheries Issues
.jpg)
Salmon Collapse: Water Is the Real Problem
Jan. 25 2010, 9:25 AM
Jan. 25 2010, 9:25 AM
Salmon Collapse: Water Is the Real Problem
Ocean conditions may have some impact on salmon, but California water is the real culprit in our salmon collapse. That is the conclusion of most experts who can look at the data with a clear eyed analysis. Marc Gorelnik, a brilliant physicist/lawyer and fisherman, has done the analysis below from publicly available data and posted this on Coastside Fishing Club's web site. The politicians who want to blame "ocean conditions" take a small piece of the truth and make it into the whole story, but Marc's post shows what is really happening.
Ocean conditions may have some impact on salmon, but California water is the real culprit in our salmon collapse. That is the conclusion of most experts who can look at the data with a clear eyed analysis. Marc Gorelnik, a brilliant physicist/lawyer and fisherman, has done the analysis below from publicly available data and posted this on Coastside Fishing Club's web site. The politicians who want to blame "ocean conditions" take a small piece of the truth and make it into the whole story, but Marc's post shows what is really happening.
“My personal belief is that we'll have a recreational season this year. Based on reasonable extrapolation from the hatchery jack numbers, we should well exceed even a cautious conservation floor for the Central Valley Fall Chinook. Nevertheless, I want to briefly revisit the causes of the collapse.
Because of self-interest, the agricultural sector and their political supporters push the theory that the collapse is due solely or primarily to poor ocean conditions, an act of God. This shifts responsibility away from California water policies and the destruction of the Delta. There's even a scientific report that suggests that ocean conditions are at fault.
The report notes that offshore upwelling was largely absent in 2005 and initially delayed in 2006. This reduced the available forage for juvenile salmon as well as birds. Any of us who spent time on the water can confirm this. The scientists suggest that these conditions increased mortality for outmigrating salmon, thereby reducing their abundance as adults. Certainly true.
This can be seen by looking at Chinook on the Russian River. The escapement numbers for 2008 and 2009 are down from the peak in 2002 through 2004, but the ratio is 3.7 to 1 (averaging 2002-04 against the average of 2008-09). That's a big difference, for sure, and I would accept that as caused by poor ocean conditions. But look at the Sacramento Index for those same years. The ratio is 15:1. If the Sacramento Index had declined by the same ratio as the Russian River, then we would have kept fishing as the abundance would have fallen to "only" 350,000.
Why did the Central Valley Chinook fare so much differently than the Russian River Chinook, with substantially identical ocean conditions? Something else, far more pernicious than "ocean conditions," had a hand in the severe drop-off in abundance.
The scientific report notes poor ocean conditions for 2005 (affecting 2004 brood year and largely 2007 escapement) and localized and short-lived poor ocean conditions in 2006 (affecting 2005 brood year and largely 2008 escapement). Ocean conditions in 2007 were better than average, so that excuse is off the table for the 2006 brood year (when 268K fish returned to spawn). Historically, that escapement size has yielded (+3 years) abundances of 700K to over 1,000K fish. So the 2009 adult returns should have been HUGE, right? Well, no. (it is interesting to note that 1,801 adults were counted at the Russian River in 2009. That's about 31% of the peak years of 2002 and 2003. If the Central Valley had done this well, we would have seen an abundance of about 420,000 fish in 2009. We missed this by a huge margin.)
Poor ocean conditions in 2005-06 fail to explain both: (1) the extent of the abundance decline in 2007 and 2008; and (2) any abundance shortfall in 2009.
And then we have the 2009 jack returns. Way up at some hatcheries, not so much at others. Why such a large variation for common (and better than average) ocean conditions? Coleman released its 2007 fish in two groups, but at the same location. There are no 2009 jack returns from one group. Zippo. Given the large sample sizes and common ocean conditions, shouldn't we expect the same rate of jack returns?
In summary, poor ocean conditions negatively affected salmon abundance, but does not account for the extraordinary decline we have seen. Moreover, from 2007 forward, ocean conditions favored better than average abundance, which we should have seen in adult returns in 2009. The fact that returns fell further than they should have, and have kept falling despite the improvement in ocean conditions, demonstrates the consequences of California's irresponsible water policies.
Because of self-interest, the agricultural sector and their political supporters push the theory that the collapse is due solely or primarily to poor ocean conditions, an act of God. This shifts responsibility away from California water policies and the destruction of the Delta. There's even a scientific report that suggests that ocean conditions are at fault.
The report notes that offshore upwelling was largely absent in 2005 and initially delayed in 2006. This reduced the available forage for juvenile salmon as well as birds. Any of us who spent time on the water can confirm this. The scientists suggest that these conditions increased mortality for outmigrating salmon, thereby reducing their abundance as adults. Certainly true.
This can be seen by looking at Chinook on the Russian River. The escapement numbers for 2008 and 2009 are down from the peak in 2002 through 2004, but the ratio is 3.7 to 1 (averaging 2002-04 against the average of 2008-09). That's a big difference, for sure, and I would accept that as caused by poor ocean conditions. But look at the Sacramento Index for those same years. The ratio is 15:1. If the Sacramento Index had declined by the same ratio as the Russian River, then we would have kept fishing as the abundance would have fallen to "only" 350,000.
Why did the Central Valley Chinook fare so much differently than the Russian River Chinook, with substantially identical ocean conditions? Something else, far more pernicious than "ocean conditions," had a hand in the severe drop-off in abundance.
The scientific report notes poor ocean conditions for 2005 (affecting 2004 brood year and largely 2007 escapement) and localized and short-lived poor ocean conditions in 2006 (affecting 2005 brood year and largely 2008 escapement). Ocean conditions in 2007 were better than average, so that excuse is off the table for the 2006 brood year (when 268K fish returned to spawn). Historically, that escapement size has yielded (+3 years) abundances of 700K to over 1,000K fish. So the 2009 adult returns should have been HUGE, right? Well, no. (it is interesting to note that 1,801 adults were counted at the Russian River in 2009. That's about 31% of the peak years of 2002 and 2003. If the Central Valley had done this well, we would have seen an abundance of about 420,000 fish in 2009. We missed this by a huge margin.)
Poor ocean conditions in 2005-06 fail to explain both: (1) the extent of the abundance decline in 2007 and 2008; and (2) any abundance shortfall in 2009.
And then we have the 2009 jack returns. Way up at some hatcheries, not so much at others. Why such a large variation for common (and better than average) ocean conditions? Coleman released its 2007 fish in two groups, but at the same location. There are no 2009 jack returns from one group. Zippo. Given the large sample sizes and common ocean conditions, shouldn't we expect the same rate of jack returns?
In summary, poor ocean conditions negatively affected salmon abundance, but does not account for the extraordinary decline we have seen. Moreover, from 2007 forward, ocean conditions favored better than average abundance, which we should have seen in adult returns in 2009. The fact that returns fell further than they should have, and have kept falling despite the improvement in ocean conditions, demonstrates the consequences of California's irresponsible water policies.
Post a Comment
All comments are moderated by the administrators.All fields are required.
