Here's a long winded response to some of the above..
Response to WinterrunRon, JerryInLodi and slimfishing‘s comments
First, the 1966 striped bass study by Don Stevens et al is still very relevant as well as the 1995 study of Clifton Court predation.
To clarify what I said about delta stripers…First lets look at the state and federal fish screening facilities…This is a good web site to see what they’re all about:
http://science.calwater.ca.gov/pdf/w...yes_052805.pdf
You will note that the major difference is that the federal pumps take water directly from Old River while the state pumps from Clifton Court Forebay. The flow from Old River through the forebay is controlled by gates in the S/E corner. The fish salvage screens are between the forebay and the pumps not the forebay and river. A better fish trapping/killing system couldn’t be built if that was what you were trying to accomplish.
The way it operates is, as water is pumped from the forebay levels drop to a predetermined point. They then open the gates to Old River (generally during the highest tide cycle of the period) When the gates are opened a wall of water 4-6’ high or higher floods into the forebay and sucks every swimming critter in the south delta into the forebay. This includes adult striped bass, largemouth bass and other predatory fish as well as salmonid smolts (at the right time of the year) delta smelt, also millions of eggs and fry and who knows what all. Once the flow stops the gates are closed till the next cycle. Once entrained in the system the adult fish are there for the rest of their fat lives and a fat life it is, with fresh food delivered to their waiting mouths with every pumping cycle. The fish that leave the forebay are either eaten or removed through the “salvage process” (which is a whole other topic and a process that sorely needs a good fix!!)
The above pumping process is what I was referring to when I was talking about striped bass stomach samples. Inside the forebay where trapped predatory fish eat whatever comes along, courtesy of the opening of the gates to the forebay, is the only place in the delta where stomach sampling has shown smolts being eaten.
I have been on DFG boats fishing and catching striped bass around man made structures all around the delta (outside of the forebay) so the DFG biologists can pump their stomachs to identify what they’ve been eating ( taking remains back to the lab if to far along in the digestive process) and never saw any smolts nor has any ever been recorded in DELTA striper stomach studies, again outside of Clifton Court Forebay!
What this implies is (aside from the tributary rivers) smolts do not occupy water that striped bass use for feeding during the passage through the delta with the exception of their entrainment at Clifton Court along with all the other fish. My point was that there is no documented evidence of “natural “ smolt predation by striped bass in the delta proper.
For JerryInLodi and slimfishing’s comments, While the alluded to 5-7% predation of wild smolts by striped bass (in the rivers) is well within the norm and wouldn’t be a concern if we had a healthy system, as I said in my previous post, most of the studies that show striped bass predation of smolts is associated with hatchery releasing and the inane methods used in that process.
As a member of DFG’s Striped Bass Stamp Fund Advisory Committee I have approached DFG about affecting some changes in their release process. I haven’t made much progress in that effort however, due to the fact that there has only been one meeting of the Committee in the last year and a half. It seems like DFG is trying to ignore striped bass and probably has their eyes on “our” (anglers) 3.7 million dollars in the stamp’s dedicated fund. In December the Committee requested a sit down meeting with the Director of DFG which has been ignored up to this point. Which may or not be an indication of the Department’s “new” attitude with respect to striped bass. (ignore them and maybe they’ll go away??!!)
Someone above mentioned the value of the striped bass fishery to the state’s economy.. One other bit of “unfinished business” of the Striped Bass Fund Committee is that we commissioned an update of the 1986 study of the economic value of the three (striped bass, salmon and steelhead ) main anadromous fisheries in the Sac/San Joaquin River system. In 1986 this study showed the value of the fisheries was a little over 2 billion dollars….It gives me pause to wonder how the DFG can let our fisheries decline to the point they have considering the UNSUBSIDIZED value to our economy!!! ( as compared to Corporate Ag water diversions and the subsidized crops they raise !)
I did see that the “new” stamp committee (Bay Delta Sportfishing Enhancement Stamp) has allocated 50 thousand dollars for “acclimation pen for hatchery smolts which means someone is carrying on with my idea on that committee..A good thing!
The net pen acclimation of hatchery smolts would go a long way to solving “predation” problems with salmonid smolts and the associated slaughter of striped bass at the release points . Instead of dumping the smolts into the mouths of waiting predatory fish as is now done, the smolts would be placed in net pens to become acclimated to the new environment, then be drizzled out of the net pens as they get towed along. This, as opposed to just dumping fish that are somewhat in shock from the experience and thus ready prey at the smörgåsbord!
There seems to be no reason not to implement this system other than overcoming bureaucratic inertia which is a very difficult process!
Mike
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