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Fraser River sockeye and why Carl Walters is correct

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  • Fraser River sockeye and why Carl Walters is correct

    http://www.seafoodnews.com/Story/943...ong-the-Fraser

    The above link is story about Fraser River sockeye salmon and having worked with Carl Walters on the Exxon Valdez review of the Skilak Lake sockeye studies I can tell you he is spot on. His recommendation to harvest when stocks are abundant and lower the exploitation rate when stocks are low is correct - but closure is seldom needed. He is advocating an exploitation rate model combined with variable escapement objectives.

    The ADF&G is making the same mistake with the trade-off between late run chinook salmon and sockeye salmon. The cost of a few hundred chinook below the MSY goal is not worth it from a biological or economic view.

  • #2
    Originally posted by Nerka View Post
    http://www.seafoodnews.com/Story/943...ong-the-Fraser

    The above link is story about Fraser River sockeye salmon and having worked with Carl Walters on the Exxon Valdez review of the Skilak Lake sockeye studies I can tell you he is spot on. His recommendation to harvest when stocks are abundant and lower the exploitation rate when stocks are low is correct - but closure is seldom needed. He is advocating an exploitation rate model combined with variable escapement objectives.

    The ADF&G is making the same mistake with the trade-off between late run chinook salmon and sockeye salmon. The cost of a few hundred chinook below the MSY goal is not worth it from a biological or economic view.
    So basically just kill the last of the Chinook and be done with it is what you are saying?

    Comment


    • #3
      Originally posted by AaronP View Post
      So basically just kill the last of the Chinook and be done with it is what you are saying?
      Aaaargh!!! The Chinook he's talking about have NEVER missed the bottom side of their yield-based escapement goal, let alone a sustainability threshold. Never. A far cry from killing off the last of them.

      Comment


      • #4
        Originally posted by AaronP View Post
        So basically just kill the last of the Chinook and be done with it is what you are saying?
        I am going to assume you do not understand the difference in goals and management approach. There is a huge difference between an MSY goal and a sustainable threshold. The MSY goal is maximum sustained yield and therefore giving up a few fish below it to allow other species to be closer to their goal and provide economic gain is a reasonable tradeoff. MSY goals are yield goals not conservation goals. Not meeting them means future yields may be impacted but the stock will be fine.

        Comment


        • #5
          I understand perfectly. I also understand that goals have been lowered time and time again in order to "reach" them. My problem is that I don't believe in managing for maximum harvest.

          It just amazes me how some folks think it all fine and good when runs meet the bottom end of the "escapement goals". Seems like we should be aiming a little higher.

          Nerka, it is plainly clear that you are on the side of killing as much as possible and just allowing what you believe to be enough. My belief is much different.

          Comment


          • #6
            Originally posted by AaronP View Post
            I understand perfectly. I also understand that goals have been lowered time and time again in order to "reach" them. My problem is that I don't believe in managing for maximum harvest.

            It just amazes me how some folks think it all fine and good when runs meet the bottom end of the "escapement goals". Seems like we should be aiming a little higher.

            Nerka, it is plainly clear that you are on the side of killing as much as possible and just allowing what you believe to be enough. My belief is much different.
            You are showing your ignorance and I was trying to be kind to you in my response the first time. But if you want to get personal then that is your problem..

            First the minimum goal you mention is an MSY goal to maximize the harvest. Your comments above show clearly you do not understand this concept or that the bottom end of the range vs the top end give similar results in average yields Next the goals have not been lowered in order to reach them. The sockeye goals in all systems have been raised over the last three decades. Chinook goals are lower for early run but late run goals are higher. Coho goals are mixed depending on the system and available data.

            Also managers do not lower goals to meet them. If you read or knew anything about the process you would know the goals are set by a separate scientific team within ADF&G which is independent of managers from most areas. So your statement is just false.

            It is not clear I want to kill as much as possible as that would not be sustained fisheries management. Again a fairly ignorant statement. I tried to be kind to you in my response to your other posts which show you have little knowledge of fisheries science but if you want to debate fishery science then you better know what you are talking about if you are going to throw stones.

            Comment


            • #7
              I couldn't read the entire article since it was password protected. Perhaps someone could cut and paste.

              However, Nerka's summary of Carl Walters premise is similar to how fisheries are managed on the Columbia Rv. Salmon fisheries are managed on a "sliding scale" where the exploitation rate is high (as a percentage of the run) when the pre-season forecast is high (as compared to the 10 year average). Conversely, the exploitation rate is much lower when the pre-season forecast is low. But this only works well when there is a fairly accurate pre-season forecast. If the pre-season forecast has lots of variability (e.g., spring Chinook), setting the exploitation rate gets really dicey, especially when you have to manage under the incidental take limits of the ESA. I would disagree that complete closures may not be necessary, given the variability in the pre-season forecast. If the confidence intervals around the average result in the possibility of dipping below replacement levels, or are approaching ESA limits, precautionary principles suggest that a complete closure is a necessary management tool, as a starter. If the runs come in higher than expected, opening the fishery is an option. But if not, it should remain closed. I would agree that closures are rarely needed if your pre-season forecast is accurate, which for the Fraser Rv sockeye, it might be very accurate.

              As you might guess, everything depends on the pre-season forecast. Our ability to manage is only as good as that estimate, and the variability around it.

              Comment


              • #8
                Originally posted by AaronP View Post
                My problem is that I don't believe in managing for maximum harvest.
                You're confused. We don't manage for "maximum harvest". We manage for maximum sustainable harvest under our Alaska Constitution's sustained yield principle.


                Originally posted by AaronP View Post
                I also understand that goals have been lowered time and time again in order to "reach" them.
                No, goals are lowered to change the sustainable level of the stock, based on scientifically justified reasons. Remember, a return of two fish each year is a sustainable run - it just doesn't leave any harvest available (yield), and its not very conservative. You can't have a goal without sustainability - the two go hand-in-hand whether the goal is lowered or raised. So it's all about finding a balance for the level of sustainability we want for the run, given all the variables and mixed-stock factors that add in - like harvest, run fluctuations, productivity, other affected fisheries, economics, allocation issues, predation, urbanization, etc.


                Originally posted by AaronP View Post
                It just amazes me how some folks think it all fine and good when runs meet the bottom end of the "escapement goals". Seems like we should be aiming a little higher.
                Meeting the bottom end of the escapement goal is meeting goals - it is the threshold where sustainability occurs based on conservative models. So when we meet it, everything is fine and good - the run is sustained. Giving the goal a narrow range, or setting it higher than necessary has ramifications in regards to run fluctuations, productivity, lost yields, affects on other stocks, etc. So I have to ask why aim higher than the goals?

                Comment


                • #9
                  Originally posted by AaronP View Post
                  I understand perfectly. I also understand that goals have been lowered time and time again in order to "reach" them. My problem is that I don't believe in managing for maximum harvest.

                  It just amazes me how some folks think it all fine and good when runs meet the bottom end of the "escapement goals". Seems like we should be aiming a little higher.
                  The original Kenai Late Run King goal established in 1988 was centered around escapements between 15,500 and 22,300 fish, with the optimum spawning escapement being around 22,300 fish. The midpoint of our current 15,000-30,000 goal is 22,500. No part of our management plan aims toward the bottom end of the goal - fisheries are still restricted when escapements above 15,000 are projected.

                  The goal has not been lowered time and again. In fact, the midpoint of the goal is actually a couple hundred fish higher than the original goal. And we are supposedly better at counting them now.

                  Comment


                  • #10
                    Originally posted by Cohoangler View Post
                    I couldn't read the entire article since it was password protected. Perhaps someone could cut and paste.

                    However, Nerka's summary of Carl Walters premise is similar to how fisheries are managed on the Columbia Rv. Salmon fisheries are managed on a "sliding scale" where the exploitation rate is high (as a percentage of the run) when the pre-season forecast is high (as compared to the 10 year average). Conversely, the exploitation rate is much lower when the pre-season forecast is low. But this only works well when there is a fairly accurate pre-season forecast. If the pre-season forecast has lots of variability (e.g., spring Chinook), setting the exploitation rate gets really dicey, especially when you have to manage under the incidental take limits of the ESA. I would disagree that complete closures may not be necessary, given the variability in the pre-season forecast. If the confidence intervals around the average result in the possibility of dipping below replacement levels, or are approaching ESA limits, precautionary principles suggest that a complete closure is a necessary management tool, as a starter. If the runs come in higher than expected, opening the fishery is an option. But if not, it should remain closed. I would agree that closures are rarely needed if your pre-season forecast is accurate, which for the Fraser Rv sockeye, it might be very accurate.

                    As you might guess, everything depends on the pre-season forecast. Our ability to manage is only as good as that estimate, and the variability around it.
                    The approach of higher exploitation on good returns and lower on smaller returns is aslo the foundation basis for escapement goal management where exploitation is driven by the goals if they are fixed. However, as cohoangler points out there are a majority of stocks with no goals and therefore the forecast does become critical.

                    Comment


                    • #11
                      Originally posted by Funstastic View Post
                      You're confused. We don't manage for "maximum harvest". We manage for maximum sustainable harvest under our Alaska Constitution's sustained yield principle.
                      Not quite. Lots of people mistakenly think the constitution mandates MSY. The constitution speaks to maximum use and benefit (and sustained yield, of course). MSY can certainly fall within those parameters, but it's not the directive.

                      Here are the relevant sections:

                      http://www.legis.state.ak.us/basis/f...sa.dll/acontxt?

                      Section 8.1 - Statement of Policy. It is the policy of the State to encourage the settlement of its land and the development of its resources by making them available for maximum use consistent with the public interest.

                      Section 8.2 - General Authority. The legislature shall provide for the utilization, development, and conservation of all natural resources belonging to the State, including land and waters, for the maximum benefit of its people.
                      Section 8.3 - Common Use. Wherever occurring in their natural state, fish, wildlife, and waters are reserved to the people for common use.
                      Section 8.4 - Sustained Yield. Fish, forests, wildlife, grasslands, and all other replenishable resources belonging to the State shall be utilized, developed, and maintained on the sustained yield principle, subject to preferences among beneficial uses.
                      "Fishing relaxes me. It's like yoga, except I still get to kill something." --Ron Swanson

                      Comment


                      • #12
                        Originally posted by MRFISH View Post
                        Not quite. Lots of people mistakenly think the constitution mandates MSY. The constitution speaks to maximum use and benefit (and sustained yield, of course). MSY can certainly fall within those parameters, but it's not the directive.
                        Huh? I didn't say the Constitution mandates MSY, or that MSY was the directive. Read what I said closer...

                        "We manage for maximum sustainable harvest under our Alaska Constitution's sustained yield principle."

                        In other words, when we have sufficient data to establish biological escapement goals (BEG), our Alaska Constitution allows us to manage for maximum sustainable yield. And BEG is exactly how the Chinook being talked about in this discussion are managed - maximum sustained yield.

                        Comment


                        • #13
                          Recall that the Alaska Constitution is the only State constitution that mentions natural resources, beneficial uses, and the concept of sustained yield. A very enlightened document indeed. Also recall that it was written in the late 1950's when the concept of sustained yield was all the rage among natural resource planners. It was a major change from the "slash and burn", "boom and bust" that historically characterized natural resource management (particularly forestry where old growth timber was cut as fast as possible, and then the loggers moved onto find more old growth to cut). It recognized that society can, and should, manage it's natural resources to maximize the benefits to it's citizens over time.

                          What has changed since the 1950's is the concept of sustained yield as it relates to the recognition of risk. Harvest levels for salmon that we believe are "sustainable" may not be due to factors beyond our control (e.g., rapidly changing ocean productivity), or other unrelated human activity (e.g., habitat loss due to watershed development). That is, there is an unknown level of risk that we are currently managing our resources in a manner that may not be sustainable. But we just don't know it yet.

                          Chinook salmon stocks in the Great Land serve as a great example. Presumably, ADF&G has been managing for "sustained yield" since the beginning of their existence. If so, why have the Chinook salmon stocks declined so precipitously in the past couple years? Wasn't sustained yield supposed to eliminate that? We only thought so. In reality, sustained yield can reduce the booms and busts, but the vagaries of the natural world continue to challenge the concept of sustained yield. Major fluctuations in salmon abundance may always be with us.

                          More and better information on the factors that influence salmon productivity (for example) will help immensely but I'm not convinced we will ever have all the answers to basic questions such as: How many salmon are going to return this year? So, while the concept of "sustained yield" is correct, finding it remains a management challenge.

                          Comment


                          • #14
                            Originally posted by Cohoangler View Post
                            What has changed since the 1950's is the concept of sustained yield as it relates to the recognition of risk. Harvest levels for salmon that we believe are "sustainable" may not be due to factors beyond our control (e.g., rapidly changing ocean productivity), or other unrelated human activity (e.g., habitat loss due to watershed development). That is, there is an unknown level of risk that we are currently managing our resources in a manner that may not be sustainable. But we just don't know it yet.

                            Chinook salmon stocks in the Great Land serve as a great example. Presumably, ADF&G has been managing for "sustained yield" since the beginning of their existence. If so, why have the Chinook salmon stocks declined so precipitously in the past couple years? Wasn't sustained yield supposed to eliminate that? We only thought so. In reality, sustained yield can reduce the booms and busts, but the vagaries of the natural world continue to challenge the concept of sustained yield. Major fluctuations in salmon abundance may always be with us.

                            While we can’t be certain as to the reasons for the current decline in AK Chinook, one thing we can be certain of – in most systems at least - is that abundance is cyclical and declines like this have happened before. In most systems that I know of - at least the major ones - these declines in abundance are not so severe as to raise sustainability issues– so long as we don’t overharvest these stocks in lean times.

                            There are many who are overstating this “decline” to accomplish their self-serving goals.
                            Careful not to fall into their trap. 10 years ago we had record levels of kings in most of our rivers. The fact that even in the midst of these “record lows” in the Kenai and elsewhere we have still had strong enough returns to achieve historic escapement goals – even after reasonable harvest in most cases – in my mind speaks to the merits of sustained yield management.


                            That said, I don’t think that a cell-phone enabled unlimited commercial powerboat trophy fishery on top of the spawning beds like we have in the Kenai is sustainable.
                            But I think we all know that.

                            Comment


                            • #15
                              Just a slight technical correct on this subject. Sustained yields does not mean the same yield every year. The models used are to maintain average sustained yields so they have the uncertain nature of a given year build into the establishment of the goals. The idea we can take out the highs and lows is also not true for some species. For example Kenai River sockeye have returned in one year at 10 million fish and other years less than 2 million or a 5x difference. However, over the last three decades the average decade return has been fairly. This is also true for sockeye salmon for the whole inlet since Kenai and Kasilof River drive sockeye. In contrast Susitna sockeye are down because of in-river issues which changed the habitat and thus the sustainable level. Kenai and Kasilof habitat has been maintained, in large part thanks to the Federal Gov who control the land use patterns.

                              Comment

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