Fish Report 2/20/13
One Spot
WX CNX
A Ph.D's Thoughts On Rec Catch Estimates
A Ph.D's Thoughts On Rec Catch Estimates
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Greetings All,
Not why I'm writing, I do have one spot left for Friday's trip. Check my 2/18/13 report for particulars. Reservation a must. Forecast I'm looking at for Saturday has changed to ESE @ 25 & rain: Trip's Cancelled.
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My old friend Capt. Harry, a retired Air Force bird-colonel who had an SR 71 Squadron for a while; Harry would have spoken the letters WX CNX instead of saying weather cancelation. He would describe deteriorating weather conditions as 'Delta Sierra' meaning, ahh, dog poo. A hard man, easily among the the hardest I ever met, we scattered his ashes at sea buoy many years ago.
Still, I wonder if even Capt. Harry would have bucked the system as senior stock assessment scientist & statistician for MD, Dr. Alexi Sharov, has.
I've copied his letter below. It strikes at the heart of what we've been working on for years; Fairness in the use of recreational catch estimates.
Our state representatives are at the Atlantic States Marine Fisheries Commission meeting this week.
You need to fwd Dr. Sharov's letter to your state's ASMFC fishery representatives. You need to.. Sea bass are scheduled for Thursday morning 2/21/13.. Here's a list of contacts: http://www.asmfc.org/
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On Thursday, tomorrow as I write, ASMFC reviews the sea bass situation. Good that it's on the agenda in the morning. Catch estimates for 2012 show Massachusetts's private boat anglers must have lost all interest in striped bass, fluke, scup & bluefish and dedicated every trip to sea bass; That's what they must have done to catch more sea bass in 6 weekends than every partyboat from RI to TX caught all year..
No, Wait. Estimates show them catching more of those species too. Summer flounder landings for May/June are up 30% in MA - Striped Bass up 20% - Bluefish are about even - & Scup, just amazing considering all the effort on sea bass; Scup were up 457 percent. MA private boat catch estimates climbed from 108,000 scup in May/June 2011 to 493,000 in 2012 and they still had time for 665,500 (MRFSS) pounds of sea bass to Rhode Island's 7,600 (MRIP) pounds. That represents a 615% increase from Massachusetts' 108,000 pounds in May/June 2011.
With absolutely no concern for tests of accuracy because none have ever occurred, recreational catch estimates are treated as a military sniper's shooting: Perfect. That's why we're in such difficulty with sea bass, because managers treat the centerpoint of each estimate's spread as perfect.
That sniper has to show his superiors what he's got on paper, has to prove it with lead down-range.
We have many, many examples of estimate centerpoints that are nowhere near correct; could never be proven because they are not true. Yet these estimate centerpoints are accepted as perfect to streamline paperwork.
You'll recall the actual statistical answer wasn't "NJ shore caught 173,100 tautog" as the centerpoint would imply; rather, "We're 95% confident the answer is between 465,000 and zero tautog."
One of the points Dr. Sharov's letter stresses is that any point along that enormous span is equally likely, not just the centerpoint.
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The problem's growing worse; converting estimates to pounds is proving to act as an error-multiplier in rebuilt fisheries. Our estimates have now become economically crippling. I truly fear if Dr. Sharov's advise is not taken to heart in the whole of our coast's management system, we'll soon see the demise of several recreational fisheries despite biological abundance.
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Estimates create a maze of smoke & mirrors, are much ado about nothing. Close two weeks in summer, add an inch to whatever size limit; liberalize regulation when estimates go low; emergency closure while many can not recall such abundance: We're calculating the odds of regulatory impact from the next estimate as a gambler might, while blinded to true biological response of our managed species.
Fishery Restoration Needs To Happen At Sea Too, Not Just On A Computer Screen.
Rec estimates have so obfuscated managed species' factual reaction to regulatory measures, our restoration system won't trouble itself to see if our corals are real, can't be bothered to see if there really is reef habitat for our reef fish, remains unconcerned with southern Mid-Atlantic cbass's increasing age at maturity.
But it'll stomp a heel into party/charter crews' bank accounts with improbable statistics; it'll teach clients to go find something else to do after decades of work creating off-season fisheries; it'll force shorter & shorter seasons while growing size limits hinder natural production.
Recreational Catch Estimates Are, Literally, Destroying The Sea Bass Fishery.
We're wanting of regulatory truth in a system deceived by its own data.
Really Needs Fixing.
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Dr. Sharov's letter lies below, unchanged & intact. Highlighted sections in BOLD, italics, underlinings & combinations thereof are stresses I have created.
Write to your state representatives. http://www.asmfc.org/
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Regards,
Monty
Monty
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Capt. Monty Hawkins
mhawkins@siteone.net
Party Boat "Morning Star"
Reservation Line 410 520 2076
http://www.morningstarfishing.com/
Capt. Monty Hawkins
mhawkins@siteone.net
Party Boat "Morning Star"
Reservation Line 410 520 2076
http://www.morningstarfishing.com/
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01. 22. 2013
To: Bob Beal, Executive Director ASMFC
From: Alexei Sharov, Maryland Department of Natural Resources
Subject: Black Sea Bass Recreational Measures in 2013
I would like to bring to your attention a serious methodological issue identified during the MAFMC and ASMFC discussion of black sea bass stock status and recreational management measures for 2013. According to the Council Memo dated November 15, 2012, the 2012 recreational catch in waves 1-4 has already exceeded the 2012 annual catch limit. Although the introduction of accountability measures required by the Magnusson – Stevens Act are delayed by the NMFS Regional Office until 2014, there is an expectation of further ACL reduction of up to 49% to account for the presumed 2012 overage. However, this overage is likely to be overstated and is primarily a result of inappropriate data treatment and issues in assessment and management methodology.
The core problem in the current management of the black sea bass fishery is inappropriate use of the recreational harvest estimates. This is a common problem that applies to any species where recreational harvest is a significant portion of the total catch.
In the current process employed by both the Council and the Commission, a point estimate from the survey is treated as the true value of actual catch. Failure to treat recreational harvest as a statistical estimate incorporating measures of uncertainty is likely to lead to wrong conclusions about the level of removals and erroneous management actions. While stock assessment models routinely address uncertainty in absolute abundance and fishing mortality rates in the form of probability distribution or a likelihood of F being over threshold, the uncertainty in recreational catch estimates is totally ignored in the current process of fishery performance evaluation, specifically when the estimated catch is compared with the annual quota. As you well know, the MRFSS/ MPRIP survey produces an estimate of annual harvest with the corresponding measure of error in the estimate in the form of proportional standard error or PSE. Even a moderate PSE can lead to the event that simply by chance our estimate of catch per angler trip in any wave, mode or area could be well above or below the true value and result in very large inter-annual variability. Abundant examples of such estimates that were considered questionable were brought to the attention of the Council, ASMFC and state agencies by many stakeholders.
MRIP staff responded to stakeholders critique with a clear statement about the nature of a survey estimate: "For an estimate to have any real-world meaning, both of these numbers (point estimate and margin of error) have to be taken into account. That's because if there is a high PSE, then we are less certain that the point estimate reflects the true value, a fact that has to be accounted for when using the data."
As you can see, MRIP explicitly warns about a proper use of the estimate and advises caution when PSEs exceed 50%. While this is clearly understood and loudly voiced by our constituency, surprisingly, this advice is currently being completely ignored by the assessment scientists and managers in the current management process.
To: Bob Beal, Executive Director ASMFC
From: Alexei Sharov, Maryland Department of Natural Resources
Subject: Black Sea Bass Recreational Measures in 2013
I would like to bring to your attention a serious methodological issue identified during the MAFMC and ASMFC discussion of black sea bass stock status and recreational management measures for 2013. According to the Council Memo dated November 15, 2012, the 2012 recreational catch in waves 1-4 has already exceeded the 2012 annual catch limit. Although the introduction of accountability measures required by the Magnusson – Stevens Act are delayed by the NMFS Regional Office until 2014, there is an expectation of further ACL reduction of up to 49% to account for the presumed 2012 overage. However, this overage is likely to be overstated and is primarily a result of inappropriate data treatment and issues in assessment and management methodology.
The core problem in the current management of the black sea bass fishery is inappropriate use of the recreational harvest estimates. This is a common problem that applies to any species where recreational harvest is a significant portion of the total catch.
In the current process employed by both the Council and the Commission, a point estimate from the survey is treated as the true value of actual catch. Failure to treat recreational harvest as a statistical estimate incorporating measures of uncertainty is likely to lead to wrong conclusions about the level of removals and erroneous management actions. While stock assessment models routinely address uncertainty in absolute abundance and fishing mortality rates in the form of probability distribution or a likelihood of F being over threshold, the uncertainty in recreational catch estimates is totally ignored in the current process of fishery performance evaluation, specifically when the estimated catch is compared with the annual quota. As you well know, the MRFSS/ MPRIP survey produces an estimate of annual harvest with the corresponding measure of error in the estimate in the form of proportional standard error or PSE. Even a moderate PSE can lead to the event that simply by chance our estimate of catch per angler trip in any wave, mode or area could be well above or below the true value and result in very large inter-annual variability. Abundant examples of such estimates that were considered questionable were brought to the attention of the Council, ASMFC and state agencies by many stakeholders.
MRIP staff responded to stakeholders critique with a clear statement about the nature of a survey estimate: "For an estimate to have any real-world meaning, both of these numbers (point estimate and margin of error) have to be taken into account. That's because if there is a high PSE, then we are less certain that the point estimate reflects the true value, a fact that has to be accounted for when using the data."
As you can see, MRIP explicitly warns about a proper use of the estimate and advises caution when PSEs exceed 50%. While this is clearly understood and loudly voiced by our constituency, surprisingly, this advice is currently being completely ignored by the assessment scientists and managers in the current management process.
A proper use of statistical theory would be to generate a confidence limit interval at the selected level of confidence using sample point estimates and a measure of error. Such an interval is a true measure of our knowledge of the size of the catch. It is important to note that any point within the specified interval is equally likely to be a true value.
In addition to the issue of survey precision, there is still a possibility of bias in total effort and catch estimates due to the reliance of current survey on random digital dialing to landline phones only. This was indicated in several reports to the ASMFC by Dr Crecco from CT DEP. His concerns about potential bias (overestimation of catch) were never fully addressed, while the new effort assessment methodology based on saltwater angler registry has not yet been implemented and tested..
While there is no immediate simple solution to the problem, there are several steps that could be recommended to the Council and the ASMFC to address this problem.
1. The inappropriateness of the use of single point estimates in management should be acknowledged by the Council's SSC and the ASMFC Technical Committees.
2. The Council and the ASMFC should stop using point estimates of recreational harvest in a quota based management system.
3. The SSC and appropriate Technical Committees should initiate a discussion and develop alternatives to current treatment of recreational harvest estimates.
Potential interim options may include using a three year running average for recreational harvest estimates or other types of smoothers and use of trend analysis. Since the ultimate goal of the Act is to avoid overfishing, the monitoring data indicating population status (changes in size and age structure through the range of the species at sea as well as fishery dependent and independent CPUE measures) should be regularly considered when developing management advice and quota setting rather than relying solely on catch estimates in the absence of regular stock assessment updates. Whenever estimates of catch seemed to be particularly high or low, the Monitoring Committee or another appropriate group should review the MRIP data with great detail to identify sources leading to the outlier estimate and provide expert judgment on believability and applicability of the estimate to be considered in the development of management advice.
Applicability of alternative ad hoc methods (i.e. Bayesian modeling) should be investigated as well. Lastly, these comments are applicable to a number of other recreationally important species managed by both ASMFC and the Council.
This letter represents a summary of my personal perspective on problems in current assessment and management process. I hope you will find these comments useful and forward this letter to the appropriate Technical Committee(s) for further consideration. I am confident that collectively we should be able to improve substantially our management methodology.
Sincerely
Alexei Sharov, Ph.D.
Stock Assessment and Analysis Program
Fisheries Service
Maryland Department of Natural Resources
In addition to the issue of survey precision, there is still a possibility of bias in total effort and catch estimates due to the reliance of current survey on random digital dialing to landline phones only. This was indicated in several reports to the ASMFC by Dr Crecco from CT DEP. His concerns about potential bias (overestimation of catch) were never fully addressed, while the new effort assessment methodology based on saltwater angler registry has not yet been implemented and tested..
While there is no immediate simple solution to the problem, there are several steps that could be recommended to the Council and the ASMFC to address this problem.
1. The inappropriateness of the use of single point estimates in management should be acknowledged by the Council's SSC and the ASMFC Technical Committees.
2. The Council and the ASMFC should stop using point estimates of recreational harvest in a quota based management system.
3. The SSC and appropriate Technical Committees should initiate a discussion and develop alternatives to current treatment of recreational harvest estimates.
Potential interim options may include using a three year running average for recreational harvest estimates or other types of smoothers and use of trend analysis. Since the ultimate goal of the Act is to avoid overfishing, the monitoring data indicating population status (changes in size and age structure through the range of the species at sea as well as fishery dependent and independent CPUE measures) should be regularly considered when developing management advice and quota setting rather than relying solely on catch estimates in the absence of regular stock assessment updates. Whenever estimates of catch seemed to be particularly high or low, the Monitoring Committee or another appropriate group should review the MRIP data with great detail to identify sources leading to the outlier estimate and provide expert judgment on believability and applicability of the estimate to be considered in the development of management advice.
Applicability of alternative ad hoc methods (i.e. Bayesian modeling) should be investigated as well. Lastly, these comments are applicable to a number of other recreationally important species managed by both ASMFC and the Council.
This letter represents a summary of my personal perspective on problems in current assessment and management process. I hope you will find these comments useful and forward this letter to the appropriate Technical Committee(s) for further consideration. I am confident that collectively we should be able to improve substantially our management methodology.
Sincerely
Alexei Sharov, Ph.D.
Stock Assessment and Analysis Program
Fisheries Service
Maryland Department of Natural Resources
