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From the Asbury Park press:
More and more scientists are breaking out of the scientific defensive circle to question the summer flounder data being used to throttle the fishery.
A criticism of the "best scientific information" used by the National Marine Fisheries Service, Mid-Atlantic Fishery Management Council and Atlantic States Marine Fisheries Commission in the past is the secrecy surrounding it.
There always is the suspicion that bad or insufficient data are used to make decisions, and secrecy feeds distrust. Information coming out of the best computer models is only as good as the data fed into them.
Partnership for Mid-Atlantic Fisheries Science, a multi-state, multi-institutional alliance has some heavy hitters in its ranks, and they are asking important questions.
The scientists working with PMAFS include Eric Powell and Ken Able of Rutgers University, Emerson Hasbrouck of Cornell University, Brian Rothschild of the University of Massachusetts, Bruce Freeman of the Jersey Coast Anglers Association, and John DePersenaire of the Recreational Fishing Alliance.
They are concerned about the assessments of summer flounder stocks made in other years, and have asked Dan Furlong, executive director of the Mid-Atlantic Council, to help them prepare for a meeting Feb. 11-12 leading up to the NMFS assessment meeting in June.
Gregory P. DiDomenico, executive director of Garden State Seafood Association, along with Freeman and DePersenaire, wrote Furlong asking for information.
"The questions that we have relate to the use of survey data and landings data in the assessment, the methods for developing from the raw data the data sets to be input into the numerical models, and the documentation supporting the parameterization of the various models used," they began. "We have been unable to find this detailed in any literature so far supplied to the subcommittee."
Raw data comes from three primary NMFS surveys (fall, winter and spring) plus state surveys.
The scientists want to know if data from the federal survey indices are all strata used or is the survey index derived from a subset of all survey strata? If the latter, they want to know what strata are used to develop the survey index.
"To be productive, the participants in the upcoming meeting must have a thorough understanding of the raw data and the data analysis that are conducted prior to numerical modeling of the stock," they pointed out.
"We have received little documentation of what may be critical decisions as to how to approach and manipulate the data prior to the numerical modeling process," they continued. "A range of questions come to mind that a document detailing the methodology would likely answer fully."
They stressed that the virtual population analysis for summer flounder is based on a number-at-age data set that is ultimately derived from an age-length key and length measurements from survey and port sampling.
"We have been unable to determine from the information provided any details on the quality of the data used for the age-length relationship," they added. "What data are used? Are the number of samples for landings sufficient over the time series?
"How good is the estimate of catch given errors induced by the existence of several ports and sampling locations?" they asked. "What is the effect of the recreational catch estimate particularly given that the estimates have such a poor reputation?
"Are there temporal or other effects of changing mesh size in the fishery or the surveys or any other differential age-specific changes in the vulnerability or availability of which we should be made aware of?" they continued.
"Are the sexes differentiated in modeling the age structure of the population? If not, is this considered a significant uncertainty?"
They also pointed out that in going over the documentation it was observed that geometric means were used rather than arithmetic means in some cases, and in the case of forecasting recruitment, for example, median recruitment was used rather than arithmetic mean recruitment.
"What dictates the decision between the use of geometric and arithmetic means and why is the median rather than the mean used for recruitment?" they asked.
"With what we have at hand, we cannot evaluate the quality of the data or reproduce in any meaningful way the intermediate data sets, model parameterizations or commutations," they pointed out.
Fishermen ask: If scientists cannot do it, what about the rest of us?
More and more scientists are breaking out of the scientific defensive circle to question the summer flounder data being used to throttle the fishery.
A criticism of the "best scientific information" used by the National Marine Fisheries Service, Mid-Atlantic Fishery Management Council and Atlantic States Marine Fisheries Commission in the past is the secrecy surrounding it.
There always is the suspicion that bad or insufficient data are used to make decisions, and secrecy feeds distrust. Information coming out of the best computer models is only as good as the data fed into them.
Partnership for Mid-Atlantic Fisheries Science, a multi-state, multi-institutional alliance has some heavy hitters in its ranks, and they are asking important questions.
The scientists working with PMAFS include Eric Powell and Ken Able of Rutgers University, Emerson Hasbrouck of Cornell University, Brian Rothschild of the University of Massachusetts, Bruce Freeman of the Jersey Coast Anglers Association, and John DePersenaire of the Recreational Fishing Alliance.
They are concerned about the assessments of summer flounder stocks made in other years, and have asked Dan Furlong, executive director of the Mid-Atlantic Council, to help them prepare for a meeting Feb. 11-12 leading up to the NMFS assessment meeting in June.
Gregory P. DiDomenico, executive director of Garden State Seafood Association, along with Freeman and DePersenaire, wrote Furlong asking for information.
"The questions that we have relate to the use of survey data and landings data in the assessment, the methods for developing from the raw data the data sets to be input into the numerical models, and the documentation supporting the parameterization of the various models used," they began. "We have been unable to find this detailed in any literature so far supplied to the subcommittee."
Raw data comes from three primary NMFS surveys (fall, winter and spring) plus state surveys.
The scientists want to know if data from the federal survey indices are all strata used or is the survey index derived from a subset of all survey strata? If the latter, they want to know what strata are used to develop the survey index.
"To be productive, the participants in the upcoming meeting must have a thorough understanding of the raw data and the data analysis that are conducted prior to numerical modeling of the stock," they pointed out.
"We have received little documentation of what may be critical decisions as to how to approach and manipulate the data prior to the numerical modeling process," they continued. "A range of questions come to mind that a document detailing the methodology would likely answer fully."
They stressed that the virtual population analysis for summer flounder is based on a number-at-age data set that is ultimately derived from an age-length key and length measurements from survey and port sampling.
"We have been unable to determine from the information provided any details on the quality of the data used for the age-length relationship," they added. "What data are used? Are the number of samples for landings sufficient over the time series?
"How good is the estimate of catch given errors induced by the existence of several ports and sampling locations?" they asked. "What is the effect of the recreational catch estimate particularly given that the estimates have such a poor reputation?
"Are there temporal or other effects of changing mesh size in the fishery or the surveys or any other differential age-specific changes in the vulnerability or availability of which we should be made aware of?" they continued.
"Are the sexes differentiated in modeling the age structure of the population? If not, is this considered a significant uncertainty?"
They also pointed out that in going over the documentation it was observed that geometric means were used rather than arithmetic means in some cases, and in the case of forecasting recruitment, for example, median recruitment was used rather than arithmetic mean recruitment.
"What dictates the decision between the use of geometric and arithmetic means and why is the median rather than the mean used for recruitment?" they asked.
"With what we have at hand, we cannot evaluate the quality of the data or reproduce in any meaningful way the intermediate data sets, model parameterizations or commutations," they pointed out.
Fishermen ask: If scientists cannot do it, what about the rest of us?
