Steelhead management/biology questios

Discussion in 'Steelhead' started by Smalma, Feb 9, 2005.

  1. Smalma

    Smalma Active Member

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    Recently there seems to have a fair amount of interest in steelhead management and biology topics so I thought I would start a thread were we could bring our collective knowledge and interest to the topic and explore those interest. I'll attempt to share my own limited knowledge and experience Answering various questions beginning with the following:

    From Kerry regading Skagit steelhead escapement numbers-
    1) who sets the goal?
    The goal is established as a co-manager (WDFW and local tribes) goal and only exist when the two parties agree.

    2) How was/is the escapement number determined?
    The federal court has set the standard as the MSY level though the parties have the option of agreeing to something other than MSY. On the Skagit there has long been some uncertainity without river specific data what the best way to estimate the MSY level should be. As a result the parties had not agreed on a single number but rather agreed year to year on the management objective. With the sharp drop in wild steelhead returns in the Puget Sound region in general and the Skagit it became apparent that a specific goal was needed (for the much of the 1990s the co-managers had agreed to cap the fishing on the wild fish at no more than a combined 16% harvest rate). At that time (following the 2000/01) run there had been enough Skagit specific data collected to make an estimate of what the MSY level for the wild Skagit steelhead might be. Depending on the recruitment model chosen the estimates of MSY varied from a low of 2,800 to a high of 4,800. The co-managers after review that data and esitmates (developed by tribal, state and private consultant under contract with Washington Trout) they opted for a goal of 6,000 (higher than any estimates of MSY) and to further limited harvest they opted to retain the harvest rate cap of 16% for runs above the goal.

    It was thought that under such management the 6,000 goal would provide some cushion or protection during poor return periods. The cap on the harvest rate would continue to allow the population to show what they may be able to do. For example if the wild run was 10,000 fish rather than fishing down to 6,000 by taking 4,000 fish they agreed to the harvest cap which in this case would result in an escapement of 8,400. Such management over the next few years should continue to produce an range of escapements so that appropriateness of the established goal could continued to be tested and revised as the data dictated.

    Tight lines
    S malma
     
  2. Luv2flyfish

    Luv2flyfish Another Flyfisherman

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    There is NO POINT in managing this resource unless ALL parties concerned do something. A native net schedule of 6 days a week (confirmed by park ranger) on the OP is NOT CONDUCIVE to any type of management. :mad:
     
  3. Nailknot

    Nailknot Active Member

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    Boldt stands legally. Railing against it won't change anything. I'm glad to see sportfishers doing their part, as this is one way to put pressure on the tribes.

    Thanks for the insights Smalma.
     
  4. TomB

    TomB Active Member

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    Thank you Smalma- I can't think of any more questions right now, but if I do, I will certainly post them.
    -Tom
     
  5. Billbob

    Billbob must escape the warren

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    There is no sport harvest of steelhead on the Skagit, right? So is that 16% figure really only a cap on the tribes? 16% for the tribal nets, 0% + hooking mortality for the state? If so, then that looks and smells like an invocation of foregone opportunity. What am I missing? Presumably I am missing something - I really doubt the tribes would pick up the state's harvestable fish. Does expressing the cap as a total harvest percentage of run change something in that regard? And how do they know what percentage they have netted while they continue to net? Hard to say what percentage of the run has been netted without knowing how many fish are showing up. Are the estimates typically overstating the actual run size? Is there any rule about spreading the netting pressure throughout the season? Eliminating the early returning wild genetics wouldn't be smart. Unless that's the plan, so that it is easier to justify hatchery fish presence.

    I'm sure I'll think of more things that confuse me.

    Jeff
     
  6. Smalma

    Smalma Active Member

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    BillBob -
    The 16% harvest rate cap is used to determine the harvest number. The tribal fishery targets what would be their share - to date no talk of foregone opportunity on the Skagit.

    The number of harvest fish would be based on the pre-season forecast. And yes you are correct in that the forecast is often off target. As you suggest the forecast over estimates the actually run during periods of decreasing marine survivals and tends to under estimate the run size in periods of increasing survivals. The last 2 years runs in most of Puget Sound have been better than expected so the escapements are more than predicted

    For the Skagit having the escapement objective set well above MSY and the harvest rate cap provides a buffer on the fisheries (harvest) so that the escapements will be above (in good times well above) MSY level.

    Tight lines
    S malma
     
  7. Smalma

    Smalma Active Member

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    A new issue/question

    On a recent thread a statement was attributed to one of the local WDFW idiots about there being too many steelhead. It was in some sort of context regarding the CnR fishery on the Skykomish.

    Perhaps what was really said that with the recent down turn in marine survivals that the carrying capacities of the local rivers under those conditions have been reduced to levels below what was considered to the MSY level under the conditions 20 years ago. How can that be?

    While river systems and the fish populations they support can and are often very dynamic that makes them difficult to grasp perhaps a simple hypothetical example will illustrate how that may occur.

    Lets assume that the freshwater survival conditions of Lunker River are constant and the spawning and juvenile rearing environments consist of two parts with one in relatively good shape and one degraded. For this example let’s assume the one in good shape on the average has a productivity 40 smolts per spawning female (a reasonable high value) while the degraded one has a productivity of only 20 smolts per female. Lets further assume that the smolt capacity for the basin is 100,000; with 65,000 coming from the better habitat and 35,000 from the poorer habitat.

    Under average smolt to adult marine survival conditions we might expect a return of 10% or 10,000 adults. The adults would be distributed based on ratio of smolt production with 6,500 adults returning to the good habitat and 3,500 to the poor habitat. Please note that at 20 smolts/female or 10 smolts/spawner it would take 3,500 spawners to produce the 35,000 smolts in the poor habitat section while in the good habitat section at 20 smolts/spawner it would only 3,250 spawners to produce the 65,000 smolts. While it would only take 6,750 spawners to “seed” all the habitat to capacity to do so would require the spawners be distributed very precisely – hand placed? If the fish were allowed to spawn randomly it would take all 10,000 spawners to insure that enough spawners would be using the poor habitat to fully seed that habitat. In effect the carrying capacity of the system would be 10,000 spawners.

    Typically estimates of the MSY escapement of system under average environmental conditions is about 60% of its carrying capacity (it can vary a lot but for this simple example lets assume again that it is so). Which means that the MSY escapement goal for this population would be 6,000.

    Not less see what would happen to the population and its dynamics if marine survival were to crash like has been seen recently in Puget Sound and the Georgia Basin. What if the survival dropped from 10% to 5%. In our example on Lunker River the return (marine survival times the number of smolts) would 5,000 adults (3,250 returning to the good habitat and 1,750 returning to the poor habitat). Please note that under these poor conditions the fish using the poor habitat can no longer replace themselves. 3,500 spawners produced only 1,750 spawners which in turn will only produce 17,500 which the generation will produce only 875 adults – in short that habitat has become a population sink and no longer able to maintain a viable population. While the better habitat’s productivity is such that it continues to be able to replace itself (though barely).

    In event under the poor survival conditions of 5% marine survival the carrying capacity of the system has been greatly reduced. In fact it is now at a level less than what was MSY under favorable survival conditions. It also means that regardless of what management actions one may take the returns are not going to improve until those survival conditions improve. Is that failure of the management paradigm or the result of the natural variation of marine survival conditions that were likely compound by degradation of the freshwater habitat (reducing its productivity as measures as smolts/spawner)?

    Don’t know if any of this makes sense to anyone. However I’m sure that we often shot the messenger when we don’t like or understand the message.

    Tight lines
    S malma
     
  8. Bob Triggs

    Bob Triggs Stop Killing Wild Steelhead!

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    Is "MSY" working?
     
  9. Trevor

    Trevor New Member

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    Umm, what does MSY stand for? Color me ignorant...
     
  10. Smalma

    Smalma Active Member

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    Trevor -
    Sorry - I sometimes forget about the alphabet soup we sometimes communicate in confuses others.

    MSY = Maximum Sustained Yield: It is the escapement point on a the spawner/recruit curve that on the average produces the largest number of harvestable fish.

    Because it is the management point the produces the largest number of fish that in theory can be killed and still maintain the population at that level it is a popular place to manage for those who want as many dead fish as possible. In the past it was often considered to be a management failure if the full number of fish was not harvest which resulted in many populations being over fished. As a consequence many folks advocating for wild fish management and protection find MSY a distasteful to be managing. To make life more complicated the Federal Courts have mandate for the Boldt Case that unless the co-managers agree the escapement goal shall be MSY.

    Bob -
    Is MSY working? I guess that it depends on ones prespective. I'm sure that most tribal communities would say yes. Other and suspect you would fall into the camp of HECK NO!

    The point in my most recent posting was that under the extreme poor marine survivals we have been seeing in Puget Sound that having an escapement goal of MSY under average survival conditions is actually the same as having a goal of carrying capacity under poor conditions -neither are limiting the population.

    FRom my prespective I see a real difference between managing to achieve MSY harvest level and sitting an escapement objective at MSY and managing the resulting fisheries to insure that the escapements will be at or preferably above the MSY level.

    As an angler my interest are two fold - conservation of the resource and have abundant fish for my angling preference. With any kind of habitat productivity what I have read regarding consrvation biology a population at or above MSY would be above population viability. So meeting my test of conserving the resource would met with a MSY escapement objective though to reduce the risk of falling below that level I would prefer to see any manage using a MSY escapement objective be well buffered to reduce the probability of management error. As an angler catches and release the vast majortiy of all wild salmonids that I catch (release all resident trout, sea-ru cutts, Dollies, STeelhead) but do keep some salmon - mostly hatchery but the occassional wild pink, sockeye or even coho that I feel are robust I would prefer that manage be well above MSY but below carrying capcity - more fish to recreate on.

    Tight lines
    S malma
     
  11. wet line

    wet line New Member

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    In my ignorant view they are trying to sustain runs of fish based upon depressed runs after the problem of low returns became overly apparent.

    There is no consideration of what was there at one time nor what could be there now.

    It is based upon minimal returning spawners, with max harvest, and still keep the run off the endangered list.

    6000 spawners on the Skagit should be enough reason to close the river down for everybody. That is less than 25% of what the river used to kick out in caught fish! And it produced that number of fish for years until it was over harvested! and minimum escapement goals were instituted. It should be maximum escapement goals and minimal harvest if the runs are going to ever come back!

    Dave
     
  12. Trevor

    Trevor New Member

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    This sounds a lot like they are trying to sustain current levels (without much of a margin for error). Is that the current paradigm? Is there any effort to restore runs to levels seen in the past?

    Trevor
     
  13. Smalma

    Smalma Active Member

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    Wet line -
    A question for you - where you would set the escapement goal in my hypothetical example given the following?
    Carryinng capacity at low marine survival (5% marine survival) = 3,250
    Carying capacity at avg. marine survivl (10% marine survival) = 10,000
    MSY at avg marine survial = 6,000
    Carrying capacity at high marinve survival(15% marine survival) = 15,000
    Carrying capacity at high marinve survival and restored habitat = 20,250

    Ignoring the whole tribal thing for the monent which of the 5 options above best fit your thoughts for the best escapement objective?

    Others have any thoughts?

    tight lines
    S malma
     
  14. Nailknot

    Nailknot Active Member

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    We can't ignore the current real habitat restrictions, nor cherry pick past banner years (many based on huge initial hatchery success) when figuring capacity. I see MSY as problematic but hardly the evil- it is just a system negotiated for all the stakeholders. Obviously the sports don't gain max opportunity overall, but we are in the game. Sports can make steps to close areas to bait/barbs, do our part within the system to affect a little bit, or mitigate our harm. If we close them all as Wetline suggests nobody will be watching or caring I think. We need to maximize rec opps within reason and keep pushing other harvesters to mitigate their kill- including the developers and city planners, tribes, commercials etc. We lose our seat at the table if we close rivers to rec fishing.
     
  15. wet line

    wet line New Member

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    Smalma, you have more knowledge than I about this but I will jump at the question anyhow.

    I would opt for something between the average survival and max. survival rates say as in your example around 12,000 targeted escapement, though 10,000 as an average may be exceptable. There is a lot to consider between those two numbers, such as is the average number of survival the norm over a long period of time. Meaning that for a 20 year period the average number is actually the number for say better than 50% of the runs.

    Harvest by those user groups that do harvest, would be the number of fish expected over the carrying capacity of the system.

    Habitat restoration would also need to be addressed and as the carrying capacity increased then escapement goals could also be increased to some hypothetical number which would insure better opportunities for the user groups.

    Nailknot, I would not go along with a complete closure of all the systems at one given time. However I do think that to close 20% of the systems for say 6 or 7 years and then reopen them and then shut down another 20% would be benefitial. Continue doing this until all systems have gone through the cycle. If needed then repeat the process. This would have to be a cooperative effort between all user groups to be succesful. The intent would be to get the runs built up to over the maximum carrying capacity which allows a harvest by the user groups that do harvest.

    Dave