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Article on Mokelumne Salmon, Threats of Hatchery Fish to Wild

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Sort of an unclear article here, not uusually so, on hatchery and wild salmon in the Moke. Basically, they have just found that a lot of hatchery fish are spawning in the wild and that this is harming the wild stock:

 

 

 

 

Paul Chinn / The Chronicle

 

About 90 percent of chinook salmon in the Mokelumne River are artificially produced, according to a genetic study.

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Wild chinook salmon are so outnumbered by hatchery-raised fish in the Mokelumne River that scientists fear they would die out if left to their own devices.

 

Only about 10 percent of the fall-run chinook that spawn in the river are naturally born fish, according to a genetic study released this past week. The dismal count of wild fish, which experts believe would be just as bad in other California rivers, means there are not enough native chinook to sustain a natural population in the river.

 

"We expected to find hatchery fish, but the sheer number of hatchery fish returning to spawn in the wild is surprising," said Rachel Johnson, a fishery biologist for UC Santa Cruz and the U.S. Bureau of Reclamation and a co-author of the study. "It looked like a healthy population of fish returning to spawn, but the reality is that without the hatchery fish the wild stocks are not sustaining themselves."

 

The study, published in the online scientific journal PLoS ONE, identified hatchery fish using a novel technique that detects traces of a hatchery diet preserved in the ear bones of adult fish. It was the first time biologists were able to quantify the percentage of farmed fish, most of which are unmarked and therefore undetectable in population surveys.

 

Genetic defects

 

The danger, experts say, is that the large number of artificially produced fish in the river could be masking health and fertility problems in the overall chinook population, which recent counts seem to indicate is recovering after several years of decline.

 

Studies by Oregon State University scientists in 2007 and 2009 found that hatchery-raised steelhead trout pass on genetic defects that hamper survival of their offspring. The study found that even hatchery fish whose parents were wild develop and pass on genetic defects severe enough to hamper the reproductive ability of their offspring. Not only did the hatchery fish leave far fewer offspring than their wild relatives, but they also reduced the fitness of wild populations when they interbred, according to the studies.

 

The Mokelumne study considered all coho that were spawned and grew up in the river to be wild regardless of whether their parents were produced in a hatchery.

 

The implication is that hatchery programs for salmonid species, including steelhead, chinook and coho, could actually be harming the natural balance and contributing to the demise of the once plentiful salmon runs in California, Oregon and Washington.

 

The Mokelumne, which is one of California's major salmon producing rivers, flows from the Sierra foothills and Camanche Dam and crosses the Central Valley. It ultimately meets the Sacramento-San Joaquin River Delta, a kind of watery crossroads for the largest run of salmon on the West Coast.

 

Population rebounds

 

The number of fall-run chinook this season has rebounded throughout the Central Valley, where pitiful returns forced a ban on commercial salmon fishing in 2008 and 2009. More than 18,000 chinook spawned in the Mokelumne in 2011 compared with 418 in 2008.

 

But Johnson said this season's count, bolstered as it is by hatchery fish, may not reflect the actual rate of fish productivity and survival.

 

"We might not be monitoring the right thing to evaluate the effectiveness of recovery efforts," Johnson said. "I can't extrapolate that this is the way it is everywhere, but at least on this river we found that the progeny from the wild fish aren't surviving enough to replace their parental generation."

 

The research team, which included scientists from the Lawrence Livermore National Laboratory, the U.S. Fish and Wildlife Service and the National Marine Fisheries Service, was able to identify hatchery fish by analyzing the otoliths, or ear bones, of fish. The bones carry a chemical signature from the marine fish meal that hatchery salmon are fed.

 

The fish in the study were collected in 2004, researchers said, so the percentage of hatchery fish in the river now may very well be higher.

 

Millions released annually

 

The Mokelumne River Fish Hatchery releases several million of the 40 million hatchery-raised chinook that are placed in California river systems every year. The Fish and Wildlife Service releases 12 million chinook smolt and the California Department of Fish and Game releases 20 million smolt annually into the Sacramento-San Joaquin River system. The rest are dumped into the Klamath River.

 

The vast majority of the chinook are farmed for the fishing industry as mitigation for construction of dams and other diversions by the state and federal water projects. It is a system that has been duplicated worldwide.

 

"We could be doing more harm than we recognize," Johnson said, "but I'm an optimist. I think this tool can be really useful in identifying wild and hatchery fish. If we can see how many wild fish there are, maybe we can start taking management actions that will help them recover."

 

 

 

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All those hatcheries were put in below dams to mitigate for the loss of spawning habitat upstream of the dams. I don't know what they thought was gonna happen. I guess this is newsworthy/journal worthy cause they can now put a better number on the percentage of hatchery fish spawning in the river channel(s).



 



BTW: I wonder if this type of data could be a possible avenue for ACWA, the "Coalition", etc to file a lawsuit to end all hatchery salmon production in the valley. headscratch.gif


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its the hatchery's fault for producing mutants and releasing them into the wild popluation

 

What "Wild Population"....you mean the anemic 10% ???....hardly enough to substain the species or a fishery....What I would like to see is the hatcheries, concentrate on collecting the "Wild" fish & promoting those genes....being that when salmon spawn, the wild genes are mixed with the hatchery fish by the mixing of the males sperm through-out the water/s column...The MAIN point being...be it Salmon, Trout, etc, etc,....NO FISH can spawn in a DRY creek bed....it's ALL ABOUT WATER!!!!.....Mark

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Quote:

Originally Posted by California Caster View Post

 

What I would like to see is the hatcheries, concentrate on collecting the "Wild" fish & promoting those genes.

 

They all did at one time, the first year each hatchery opened. Then they "promoted those genes" poorly, cause back in the day they just wanted numbers without much regard for strains or seasonal runs. Now it's all a convoluted mess... mixed runs from different watersheds, and mixed runs from within the same watershed (fall run spawning with spring run cause the dams don't allow for separation in space). ESA and ESU's are a fricking joke in the Central Valley imo. Hard to express those original genes now. Some are trying. The Feather River hatchery is one, maybe some others, I dunno.

 

 

 

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They all did at one time, the first year each hatchery opened. Then they "promoted those genes" poorly, cause back in the day they just wanted numbers without much regard for strains or seasonal runs. Now it's all a convoluted mess... mixed runs from different watersheds, and mixed runs from within the same watershed (fall run spawning with spring run cause the dams don't allow for separation in space). ESA and ESU's are a fricking joke in the Central Valley imo. Hard to express those original genes now. Some are trying. The Feather River hatchery is one, maybe some others, I dunno.

 

 

All very good points..With the salmon strain/s being so intermixed & deluted....the new name should be....."Rainbow Salmon".....Mark

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Quote:

Originally Posted by California Caster View Post

 

...the new name should be....."Rainbow Salmon".....Mark

 

No kidding, in the central valley anyhow. Nothing here is what it once was, cause the valley is nothing like what it was when these things started evolving...

 

 

 

- Most decent size rivers in the foothills are dammed.

 

- The hydraulic regime and seasonal flows of every one of those rivers has changed (as it has in the Sac/SJ of course).

 

- The valley rivers and delta have almost no riparian area or seasonal floodplains cause they're mostly strait-jacketed with riprap.

 

- There are more than 20 introduced fish species in the valley. The delta now resembles the Mississippi River in its fish assemblages.

 

- I don't know how many introduced invertebrates there are, but there are many, from clams to zooplankton. They matter... a lot!

 

- Introduced plants dominate the entire valley, most of the submerged aquatics are introduced too. Mostly from Asia, but the Mississippi fish like em... a lot!

 

- Chemicals are now in the water that weren't a few hundred years ago.

 

 

 

Sheesh, the valley and all of its waterways aren't native anymore, not even close. I don't see anything in the list above that makes me believe a "native" fish or strain of fish, from winter-run salmon to delta smelt, is going to continue to evolve naturally. Too late. Sorry for the rant, but I wish the fisheries managers in the valley would make lemonade from their lemons instead of trying to squeeze out orange juice.

 

 

 

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