Ask An Expert

Taking Stock of New England Fish: Part 4

Fisheries biologist Mike Palmer

Mike Palmer is Research Fisheries Biologist in the Population Dynamics Branch of the Northeast Fisheries Science Center. Our laws indicate that the best available science be used to make fishery management decisions. How does the Northeast Science Center achieve this goal?

Mike Palmer: We take many steps to ensure that the science produced through the stock assessment process constitutes the best available science. One of the ways we do this is by ensuring that the entire stock assessment process is open to the public and by strongly encouraging fishermen and other interested stakeholders to participate. Keeping the process transparent ensures that all available ideas, data and methods can be considered.

Another way in which we ensure that the results constitute the best available science is by using working groups to develop stock assessments. While much of the actual assessment work is performed by Northeast Fisheries Science Center assessment scientists, the initial decisions about what data and which models to use, and the final assessment are the products of working groups that include a wide range of participants including NMFS scientists, policy analysts, state scientists, academic scientists, fishery management council staff, industry representatives, non-government organizations, and hired consultants.

Finally, almost all assessments undergo some form of external peer-review before they are used for fishery management. This means that the scientists in charge of reviewing the assessment, the external peer reviewers, were not involved in developing the assessment or in any of the working groups, and do not have a vested interest in the assessment results. These external peer-reviewers are typically well-respected stock assessment scientists, but they come from other countries or other parts of the United States. The external peer review helps ensure that the review is objective and based solely on the scientific merits of the assessment.

TF: In your opinion, what are the most challenging aspects of fisheries stock assessments and modeling?

MP: The most challenging aspect of stock assessments is ensuring the quality and completeness of the data that are used. The amount of work required to construct assessment data sets is underappreciated. Stock assessment scientists are generally not involved in the day-to-day collection of fisheries data, but we must fully understand the characteristics of the underlying data and data collection programs to ensure that we use this information correctly.

Also, we commonly do not have all of the data we need for an assessment. In these situations we must develop ways to estimate the necessary data. A good example of this is characterizing total fishery catches back in time. For many New England groundfish stocks, we have landings time series dating back 50 or more years. However, information on fishery discards only extends to 1989 when the Northeast Fisheries Observer Program began. If discards are an important component of fishery catches and we want to start our assessment before 1989, say 1977, we need to estimate discards from 1977 to 1989. These types of tasks are difficult and time consuming and add additional, but often times necessary, uncertainty into the assessment.

Another difficult aspect of stock assessments is effectively communicating the stock assessment process and results to the wide-range of potential end users. The stock assessment reports are by necessity hundreds of pages long and filled with jargon and technical terms that are not readily digested. The assessment report is focused on describing all of data, methods, and models used in a way that is useful for the peer reviewers and fisheries managers. However, we need to do a better job of getting the information out in a way that other, less technically oriented audiences, can understand.


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