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Thread: Pikeminnow Infestation On The American?

  1. #21
    Join Date
    Oct 2008
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    California
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    Default Origin of Russian River pike minnows

    Very nice pictures of pike minnows! By the way, the name was changed several years ago from squawfish to pike minnow to be more sensitive to Native Americans. The origin of some Russian River fishes is an interesting story. From research for our upcoming new book, California Winter Steelhead - "Pike minnow (a.k.a. squawfish) are native to the Sacramento/Sa Joaquin river drainage. The native fish assemblage of the Russian River is somewhat uniquely similar to that of the Sacramento-San Joaquin river drainage. The similarity is theorized to have occurred from a geologic linkage of the river to the Sacramento River via Clear Lake, located northeast of the Russian River in Lake County. It is thought that several million years ago, Clear Lake drained into the Sacramento River via Cache Creek as it does today. This early linkage allowed native fishes from the Sacramento River system to populate Cache Creek and Clear Lake. Cache Creek was subsequently blocked by a lava flow forcing Clear Lake to drain westward into Scott Creek via Cold Creek and the Blue Lakes, and then into the Russian River. This allowed several native fish species from the Sacramento/San Joaquin river drainage to populate the Russian River." Over 50 miles of the Russian River drainage was chemically treated many years ago by California Department of Fish and Game personnel reduce nongame fish populations to enhance salmon and steelhead. Nonetheless, nongame fishes eventually rebounded from the treatment.

    Dennis
    www.dennisplee.com

  2. #22
    Join Date
    Jul 2006
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    Petaluma Ca
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    686

    Default

    "several million years ago"
    Definitely not necessary to go back so far to find the most destructive period, environmentally, to the river. Several decades should do fine. Through pollution and water robbing we have damn near completely decimated ANY fish sustaining environs in the river. What will live after we eliminate even the squawfish?
    ....lee s.

  3. #23
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    Dec 2006
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    1,067

    Default

    Just because a fish is native, doesn't mean it cannot become a nuisance when the habitat it shares with other native species is drastically altered and/or destroyed.

    Unfortunately, the increase in range and numbers of native Sacramento Pikeminnows and hardheads is due to human intervention and habitat alteration and destruction.

    The trend toward lower, warmer water, which has occurred in part due to 5 years of drought but mostly because of excess water exports over the last 25 years, has certainly favored the biological success of these cyprinids while putting salmonids at an obvious disadvantage.

    Even in my lifetime, I have witnessed a steady increase in numbers of pikeminnows and more recently, hardheads on the American River.

    In comparison to striped bass, which are mostly seasonal predators in the American River, feeding on salmon and steelhead fry and smolts... pikeminnows are present year around and consume salmonids in nearly all phases of their respective life cycles. They are known to eat eggs, alevin, fry and smolts as well as young adult steelhead and can do so before and after the seasonal migrations of striped bass.

    Fecundity and biological fitness also put pikeminnows at an extreme advantage over salmon and steelhead.

    Female salmon and steelhead respectively lay 5,400 and 5,000 eggs on average. A female pikeminnow lays 15,000-40,000 eggs.
    Salmon and steelhead require water temps of 56°F or less for optimal survival of eggs. Pikeminnow eggs flourish in 64°F
    Salmon and steelhead eggs require the digging and monitoring of a redd or nest. Pikeminnows merely broadcast their eggs loosely on to a gravel substrate and the eggs fall into the interstitial spaces.
    Salmon eggs require approximately 7.4 weeks to hatch and steelhead require 4 weeks. Pikeminnow eggs hatch in 4-7 days.

    Now, I'm not a fisheries biologist nor am I an expert in predator/prey relationships between cyprinids and salmonids but a lot of time on the water and a bit of common sense has suggested to me that an increase in numbers of pikeminnows and hardheads and lower numbers of salmonids is at least in part causation and not just correlation.

    At what point do we intervene to mitigate for a population explosion caused by a prior, human intervention? I suppose that is the golden question here...

    I would prefer reestablishing higher and colder flows on the AR to putting a bounty on the pikeminnows but good luck with that one.

    On a recent tour of the Nimbus Hatchery by the Golden Gate Salmon Association, it was revealed that a temperature sensor and control device on the upstream side of Folsom Dam is broken. This apparatus is critical to providing cold water to both the hatchery and the lower American River in the fall when salmon migration and spawning is at its peak. The B.O.R. and Army Corps each task each other with the responsibility for fixing it.

  4. #24
    Join Date
    Sep 2010
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    Granite Bay, CA
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    Steelies/Mark, thanks for all the info, dire as it may be. Maybe the seals or stripers will gobble them up.

    Flows are about to start going up: https://cdec.water.ca.gov/dynamicapp...:40&span=7days
    DATE / TIME REL SCH
    05/13/2020 07:00 1500 cfs
    05/13/2020 08:00 1750 cfs
    Showing 1 to 2 of 2 entries

    ...But based on what you're saying, that won't flush them out.

    Better temperature management would be great. It would be nice if that new top release system on Folsom Dam could be employed in this regard.

    PS the wild 18" mykiss I caught below the hardhead pod was fat as hell -- probably gorging on eggs. At least one creature was benefitting...
    TroutSource.com
    we deliver the river

  5. #25
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    Dec 2006
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    Quote Originally Posted by Troutsource View Post
    Steelies/Mark, thanks for all the info, dire as it may be. Maybe the seals or stripers will gobble them up.

    Flows are about to start going up: https://cdec.water.ca.gov/dynamicapp...:40&span=7days
    DATE / TIME REL SCH
    05/13/2020 07:00 1500 cfs
    05/13/2020 08:00 1750 cfs
    Showing 1 to 2 of 2 entries

    ...But based on what you're saying, that won't flush them out.

    Better temperature management would be great. It would be nice if that new top release system on Folsom Dam could be employed in this regard.

    PS the wild 18" mykiss I caught below the hardhead pod was fat as hell -- probably gorging on eggs. At least one creature was benefitting...
    There's a lot more to it... The AR historically dried up in the fall. The dams and releases have changed the dynamic of flow regime considerably. I am certain the spawning gravel projects are also making the river wider and shallower in many areas along the river which is contributing to warmer temps especially during low flows. You cannot add tons of gravel without first excavating dirt and expect anything less. The steelie you caught was likely full of salmon and/or steelhead fry.

  6. #26
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    Sep 2010
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    Granite Bay, CA
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    Over the last 365 days, water temps on the A flipped from being below average to being above average in November. Now they're about 5 degrees above average. Most of the data is provisional so maybe this thermometer is broken, too.
    Click image for larger version. 

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    If you go back 10 years, it looks like 2015 was by far the worst -- peaking at about 72 degrees, 8 degrees above average.

    Click image for larger version. 

Name:	AR Temps 10 years.JPG 
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    TroutSource.com
    we deliver the river

  7. #27
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    Sep 2010
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    Granite Bay, CA
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    Quote Originally Posted by STEELIES/26c3 View Post
    I got on a 45 minute striper boil in the rain this evening that produced a fish per cast and some BEASTS!
    Doesn't get any better than that.

    I'm in a BWO state of mind today but unfortunately have to work.
    TroutSource.com
    we deliver the river

  8. #28
    Join Date
    Jun 2012
    Location
    SacOfTomatoes, CA, USA
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    Quote Originally Posted by STEELIES/26c3 View Post
    There's a lot more to it... The AR historically dried up in the fall. The dams and releases have changed the dynamic of flow regime considerably. I am certain the spawning gravel projects are also making the river wider and shallower in many areas along the river which is contributing to warmer temps especially during low flows. You cannot add tons of gravel without first excavating dirt and expect anything less. The steelie you caught was likely full of salmon and/or steelhead fry.
    Talk about wide runs..... boy are there a bunch now! Just flat water where no fish young could hide in... or adult for this matter.
    Aron-



    "I own a time machine, but it only moves forward at regular speed..."

    "So many rivers to fish so little time!"

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