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Thread: Hatchery Fish in Fishin Hole(Homer)

  1. #1

    Question Hatchery Fish in Fishin Hole(Homer)

    Just wondering if anyone knows if the stocked fish in the fishing hole have their adipose fins clipped. To my knowledge I thought all stocked salmon had the adipose fin clipped?

  2. #2

    Default

    Those stocked fish do not have their adipose fins clipped. The only stocked fish with ad-clips are Crooked Creek, Ninilchik, and Deception Creek. Those locations have wild stocks and hatchery reared fish. F&G only take eggs from wild fish, so the ad-clip is needed so F&G can readily distinguish a wild fish. All the hatchery fish have an otolith mark, but not always an external mark.

  3. #3
    Member homerdave's Avatar
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    Default otolith mark?

    could you explain what you mean?
    Alaska Board of Game 2015 tour... "Kicking the can down the road"
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  4. #4

    Thumbs up Homer Fishing Hole

    Thanks for the info on hatchery fish, I just wanted to make sure that the king I caught in the fishing hole was supposed to be there. No clipped fin, just like you said. The fish on average sure aren't very big down there are they. I would bet 15-20 pounds. But they are bright chrome colored and good to eat.

  5. #5

    Default Otoliths

    Otoliths are paired crystalline structures of the inner ear composed of calcium carbonate and protein that are located in the skull of teleost (bony) fishes that aid in balance, orientation, and sound detection. There are three pairs of otoliths that differ is size, shape, and function: the lapilli, asterisci, and sagittae. Because the crystalline matrix is laid down incrementally and deposition varies spatially and temporally, these structures provide a record of a fish's life history. The sagittae are the largest and are typically used for life history studies and thermal mark recovery.

    Exposing a fish to different temperature regimes causes distinct rings or "thermal marks" to appear in otoliths. By manipulating temperature profiles during early incubation, unique mark patterns can be created to identify the broodyear and hatchery of origin for hatchery-raised fish. This marking procedure is 100% effective, permanent, and has little or no impact on fish health. The fish, however, must be sacrificed in order to recover a thermal marked otolith. Thermal marks are varied by changing the number of rings and/or bands, as well as the spacing within and between them.


    Exposing a fish to a solution of strontium chloride hexahydrate (SrCl - 6H20) at approximately 3,000 ppm for 24 hours creates a fluorescent band in the otolith that is visable when viewed with a scanning electron microscope equipped with a backscatter electron detector. By subjecting the fish to a series of exposures, unique patterns are created in the otolith that can be used to identify broodyear and hatchery of origin. This marking procedure is 100% effective, permanent, and has little or no impact on fish health. The fish, however, must be sacrificed in order to recover a strontium-marked otolith.

  6. #6
    Member homerdave's Avatar
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    Default thanks

    i knew that that kind of otolith marking was possible, but i did not know we were using it here.
    i did CWT (coded wire tag) recovery in the homer area for 6 years, and was just curious if fish and game was using hatchery generated scale or otolith I.D.
    i'll ask nikki about it
    Alaska Board of Game 2015 tour... "Kicking the can down the road"
    http://www.alaskabackcountryhunters.org/

  7. #7
    Member fullkurl's Avatar
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    Default fascinating technology...

    Thanks for the technical breakdown, Akkona. I didnt know that salmonoid aging, etc. was so advanced.




    Frank

  8. #8

    Default Coded wire tags

    homerdave,

    Due to requirements by the Tag Lab, any fish that has an adipose clip must have a coded wire tag. So Ninilchik, Crooked Creek, and Deception Creek all still have CWT. The rest of the releases are all thermal marked otoliths with no ad-clips. As you can expect, CWT cost a lot more than marking otoliths.

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