DAVE SCHRECK holds one of the presumed culprits at DVL.

Fishermen are often criticized or even dismissed for relying on their personal observations to draw them to certain conclusions. Yet while the lake regulars may not actually work as “fishery biologists,” a consensus is being formed over the condition of Diamond Valley Lake.

Its called “anecdotal” evidence because it’s not finitely measured, but going back three Octobers, the amount of surface activity (as relates to bass foraging on shad) has dipped–significantly. And it’s not for a lack of bass, but by all accounts, it reflects a lack of threadfin shad.

They’re not observed on sonar; they’re widely unseen in early summer at the usual spawning time; and there is barely any available for guides or other anglers to net for bait–as there was just a few years back.

And why are there fewer shad?  Some argue it has to do with the original threadfin’s arrival in the lake–not by stocking–but rolling in with the water imports. They say these did not come in great enough numbers to offset predation.

Likewise, based on shad conditions on other clear water reservoirs and river systems, a lack of baitfish also can be attributed to infertile conditions that make it hard for the shad to thrive past the larval stages.

But the greater likelihood is that shad numbers are down because of predation by stripers–another gamefish rarely seen boiling near the surface anymore. The stripes have established a foothold and their numbers are unlikely to allow much of any shad spawn to make it to maturity.

Guide Gregg Silks says as much. “We can barely find any shad to net, and now we are catching stripers in 30 to 60 feet on cut anchovies or sardines. You have to meter a lot, but when you find them you can catch limits of 4- to 7-pounders. They are hungry.”

Of course, shad are not the only forage in the lake. There are smelt (Silks says three species) and there are shrimp, sculpin, crayfish, small bluegill and other young of the year. (Yeah, they still plant some trout, but those don’t help the one to three-year old bass). But it’s pretty obvious what the consequences can be if one major food source is eliminated.

“Predators eat what’s most available,” Silks reminds. He, and Bill Siemantel have both commented previously that the first trout plants of the season on any lake don’t draw the big fish to the ramp, or give them an instant taste for swimbaits. The bass (and stripers) stay with the shad schools until it’s expedient to eat the bigger meals.

But if the shad numbers cannot be restored (though I would invite DVL managers to do what Vail Lake did in the 1980’s–come and take a few 50-gallon drums full of shad from Lake Elsinore), then the stripes will be forced to eat what’s next most available on the menu. And they will do it well.

How much the striper presence will change the future of Diamond Valley bass fishing remains to be seen. But you don’t need a team of scientists to confirm the lake is changing.

 

 

 




8 Responses to “DVL: Anecdotal evidence points this way”


by Terry Battisti

Interesting topic George. I’ve had a number of conversations with Wayne Gustaveson (Lake Powell Fisheries Biologist) on this subject and he’s told me about the cyclic nature of threadfin shad populations. It’s been shown in a number of fisheries biologist reports that threadfin are on a seven-year cycle. Essentially, threadfin population booms for a few years and they eat themselves out of food (zooplankton). Because young-of-the-year bass and stripers feed on zooplankton too, their populations also fall. The threadfin then begin feeding on other sources but there generally aren’t enough of those to sustain their population.

What ends up happening is the shad boom for a few years then bust. The striper population follows the shad population. Then when the zooplankton population increases again, the shad come back as does the stripers. This takes about seven years to run full circle according to Wayne.

You may be at the beginning (or middle) of one of these cycles at DVL.

Terry

Threadfin shad are phytoplankton eaters; no plankton no food for the threadfin. Doesn’t matter how many threadfin you plant, without fertile water for the phytoplankton, the threadfin become prey quickly without anywhere to hide at night.
Tom

by Dave Schreck

The other White meat “Striper”

I wonder what the chances are for DVL to produce say, 20lb plus largemouths, now that they are no longer at the top of the food chain.

The best laid plans…..

by George Kramer

Chances? Homegrown or imported? 😉 But in truth, that’s a very, very good question, cc.

by Guy Williams

Imported? LMAO!! That’s the only chance!!

DVL was planted with FLMB during the initial filling period in 1999/2000, that would make those bass over 12 years old.
Those bass had everything in their favor and should have grown to be giants by now. Max life span is about 15 years, max weight period is around the 12 year mark, so this should be the year for DVL.
Tom

the sky is falling, the sky is falling…. The sad thing is I’ve been telling the bass fishing community for at least the prior 3-4 years this was coming and to harvest every striper they caught up to their limit, no matter what size. They mostly threw them back because they don’t eat fish or didn’t want to deal with them. You are either part of the solution or part of the problem.