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Thread: Is Deshka Chinook SEG too low?

  1. #21
    Member fishNphysician's Avatar
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    Quote Originally Posted by Nerka View Post
    Please define where on the production curves this is located? Are you talking about Maximum Abundance? If so if runs decrease Max Abundance will also decrease. Not sure how you define what you are promoting. Are you using something other than a production curve?.
    To keep it in terms of the entrenched paradigm, Ricker curve at R-max.... top of the roller coaster.... to the right of R-msy and to the left of equilibrium.
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  2. #22
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    As I recall, the peak of the curve represents the number of adults needed to maximize the number of recruits. On either side of that point, the number of recruits decreases, perhaps precipitously depending on the shape of the curve. That would be max abundance.

    It might not be max sustained abundance, but I'm not sure anything about a Ricker curve can be considered 'sustained". It's been shown that MSY can produce maximum yield but it is certainly not sustainable (largely due to external factors that limit productivity).

  3. #23
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    Any stock purportedly managed for a rec priority needs be managed for MSA.
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  4. #24
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    Quote Originally Posted by fishNphysician View Post
    Any stock purportedly managed for a rec priority needs be managed for MSA.
    OK, Please tell us what the MSA is for the Deshka. The truth is, you can't. Because there is no such critter. It changes from year to year due to the variety of external factors that Cohoangler mentioned. But go ahead, take a stab at it and tell us what you think that number is. And while you are at it, maybe explain why, if it works, it shouldn't be used for fisheries that are purportedly managed for commercial priority also or even a variety of priorities? It sounds like a panacea for all that ails salmon stocks.
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  5. #25
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    Quote Originally Posted by twodux View Post
    OK, Please tell us what the MSA is for the Deshka. The truth is, you can't. Because there is no such critter. It changes from year to year due to the variety of external factors that Cohoangler mentioned. But go ahead, take a stab at it and tell us what you think that number is. And while you are at it, maybe explain why, if it works, it shouldn't be used for fisheries that are purportedly managed for commercial priority also or even a variety of priorities? It sounds like a panacea for all that ails salmon stocks.
    See post #21.... for a harvested population, the MSA escapement occurs at the apex of the Ricker curve.

    The historic bias of fishery managers clinging to the MSY-mantra is because that is theoretically where the difference between escapement and recruitment is greatest.... allowing that difference to be "sustainably" removed from the pool of adult recruits. This is the essence of the "yield" concept.... the amount that can theoretically be removed (exploited/harvested) from the adult return... and managing to maximize that yield.

    MSA occurs at a higher spawner escapement where recruitment is greatest. This works better for a rec fishery dependent on opportunity. For an angler, opportunity starts with a bite. And since we know they all ain't biters, maximizing opportunity is predicated on maximizing abundance. In a rec fishery, more fish means more bites which means more opportunity. The theoretic "yield" in that scenario is admittedly less than at the MSY escapement.... but for someone fishing for recreation, the importance of dead fish in the box is not as great as in a commercial fishery where it is 100% all about the dead fish in the box.
    "Let every angler who loves to fish think what it would mean to him to find the fish were gone." Zane Grey
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  6. #26

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    This is a good thread to stimulate conversation-
    You use the term MSA but I believe the correct term is MSR or more recently MSP.
    The term MSR has traditionally been called “maximum recruitment” (Rm; Ricker 1975, pgs 283-285), more recently “maximum sustained production” (Fleischman et al. 2012). One way to define it is the maximum point of the stock-recruit model where average recruitment over time is at the peak.

    The state policy for escapement goal states- "maximum sustained yield" or "(MSY)" means the greatest average annual yield from a salmon stock; in practice, MSY is achieved when a level of escapement is maintained within a specific range on an annual basis, regardless of annual run strength; the achievement of MSY requires a high degree of management precision and scientific information regarding the relationship between salmon escapement and subsequent return; the concept of MSY should be interpreted in a broad ecosystem context to take into account species interactions, environmental changes, an array of ecosystem goods and services, and scientific uncertainty;"

    One of the key elements to MSY is maintaining harvest regardless of run strength to stay within the range.
    So should a sport fishery on Lake Creek or other streams with the only enumeration is after the season aerial index counts have a goal that requires the the precision that MSY states be the appropriate goal, in other words should be have a goal that we can't manage for? On a river like the Deshka we do have some real time counting( weir) but does the sport fishery have the harvest power to stay within the goal on large returns?

    I would love to hear thoughts on this.

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