Improving the Collection, Management, and Use of Marine Fisheries Data - Softcover

National Research Council ; Commission On Geosciences, Environment, And Resources ; Ocean Studies Board

9780309070850: Improving the Collection, Management, and Use of Marine Fisheries Data

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ISBN 10: 0309070856 ISBN 13: 9780309070850

Publisher: National Academies Press, 2000

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Congress has promoted fisheries science for over a century and its involvement in fisheries management took a great leap forward with passage of the Fisheries Conservation and Management Act of 1976. In the past decade, Congress has requested advice from the National Research Council (NRC) on both national issues (e.g., individual fishing quotas and community development quotas) and the assessments related to specific fisheries (Northeast groundfish). This report was produced, in part, in response to another congressional request, this time related to the assessments of the summer flounder stocks along the East Coast of the United States. Following the initial request, the NRC, National Marine Fisheries Service (NMFS), and congressional staff agreed to broaden the study into a more comprehensive review of marine fisheries data collection, management, and use.

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Ocean Studies Board, National Research Council

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IMPROVING THE Collection, Management, and Use of Marine Fisheries Data

NATIONAL ACADEMIES PRESS

Copyright � 2000 National Academy of Sciences
All right reserved.
ISBN: 978-0-309-07085-0

EXECUTIVE SUMMARY............................................................................................................................................................................11 INTRODUCTION...............................................................................................................................................................................9Data Collection..............................................................................................................................................................................12Biological Data..............................................................................................................................................................................12Social and Economic Data.....................................................................................................................................................................13Data Management..............................................................................................................................................................................14Data Use.....................................................................................................................................................................................15Assessments..................................................................................................................................................................................15Regulations and Management...................................................................................................................................................................17Content of Report............................................................................................................................................................................192 SUMMER FLOUNDER: REVIEW AND INSIGHTS.......................................................................................................................................................20Introduction.................................................................................................................................................................................20Summer Flounder Assessment Issues............................................................................................................................................................21Questions Related to the Biology and Population Dynamics of Summer Flounder..................................................................................................................22Do the summer flounder found in waters north of Cape Hatteras comprise a unit stock of fish?.................................................................................................23What natural mortality rate is appropriate to use in summer flounder assessment models?......................................................................................................25Are there differences between the growth and mortality of male and female summer flounder (sexual dimorphism) and, if so, how do the differences affect the assessment?.....................29Questions Related to Summer Flounder Sampling................................................................................................................................................30What are the appropriate survey and commercial catchabilities of summer flounder?............................................................................................................30Do problems with determining the age of summer flounder discredit age-based assessments?.....................................................................................................38Are effort data used appropriately and are the effects of effort changes incorporated properly?..............................................................................................40Is the observer program for summer flounder adequate?........................................................................................................................................41Can and should state surveys be standardized?................................................................................................................................................43Is the catch from recreational fishing estimated properly?...................................................................................................................................44Can the precision of data be improved?.......................................................................................................................................................46Questions Related to the Information Content of the Model and Model Assumptions Currently in Use.............................................................................................51What information does each model structure require and how do these requirements relate to information in the data?..........................................................................51Possible Improvements to the Summer Flounder Data Sets.......................................................................................................................................54Tracking and Management of Data Precision....................................................................................................................................................57A Role for Commercial and Recreational Fishermen in Data Collection..........................................................................................................................57New Sources of Recreational Fishery Data.....................................................................................................................................................573 GENERAL ISSUES IN THE COLLECTION, MANAGEMENT, AND USE OF FISHERIES DATA....................................................................................................................59What Are Fisheries Data?.....................................................................................................................................................................59Who Uses Fisheries Data?.....................................................................................................................................................................60Data Needed for Different Management Methods.................................................................................................................................................62Current State of the Fishery.................................................................................................................................................................62Management Goals and System Response.........................................................................................................................................................64Management Actions...........................................................................................................................................................................64Data Quality Required........................................................................................................................................................................65Methods of Data Collection...................................................................................................................................................................66Data from Ceremonial and Subsistence Users...................................................................................................................................................66Data from Fishery-Independent Surveys........................................................................................................................................................66Ecosystem Data...............................................................................................................................................................................79Environmental Data...........................................................................................................................................................................81Fishery-Dependent Data.......................................................................................................................................................................81Cooperation, Communication, and Review.......................................................................................................................................................102Data Management..............................................................................................................................................................................112Confidentiality..............................................................................................................................................................................112Institutional Arrangements for Data Management...............................................................................................................................................112Fisheries Data Management Systems............................................................................................................................................................113Commercial and Cooperative Data Management...................................................................................................................................................117Data Quality Control Procedures..............................................................................................................................................................118Technologies for Data Management.............................................................................................................................................................126Data Use.....................................................................................................................................................................................127Uncertainties of Data in Stock Assessments...................................................................................................................................................127Access to Data...............................................................................................................................................................................129Management Information Needed by Councils....................................................................................................................................................129Fisheries Data Discovery.....................................................................................................................................................................130Cooperation and Communication................................................................................................................................................................1304 FINDINGS AND RECOMMENDATIONS...............................................................................................................................................................131Improving Data Collection....................................................................................................................................................................133Matching Data Collection Costs to Benefits from Fisheries....................................................................................................................................133Greater Use of Fishery-Dependent Data........................................................................................................................................................135Minimizing and Accounting for "Data Fouling".................................................................................................................................................136Fishery-Independent Surveys..................................................................................................................................................................136Data from Commercial Fisheries...............................................................................................................................................................142Data from Recreational Fisheries.............................................................................................................................................................147Auxiliary Information........................................................................................................................................................................150Cooperation and Communication................................................................................................................................................................154Review.......................................................................................................................................................................................155Improving Data Management....................................................................................................................................................................156Defining User Groups and User Needs..........................................................................................................................................................156Databases and Data Management Systems........................................................................................................................................................156Institutional Arrangements...................................................................................................................................................................157Implementing Standards and Improving Quality Control.........................................................................................................................................158Improving Technologies.......................................................................................................................................................................158Review.......................................................................................................................................................................................159Improving Data Use...........................................................................................................................................................................159Data in Stock Assessments....................................................................................................................................................................159Access to Fisheries Data.....................................................................................................................................................................160Confidentiality..............................................................................................................................................................................160Matching Management to Data Available........................................................................................................................................................161Cooperation and Communication................................................................................................................................................................161Uncertainty in Data, Models, and Model Outputs...............................................................................................................................................163Review.......................................................................................................................................................................................164Research Needs...............................................................................................................................................................................165REFERENCES...................................................................................................................................................................................166APPENDIXESA Committee Biographies......................................................................................................................................................................177B Acronyms...................................................................................................................................................................................179C Evaluation of Summer Flounder Surveys......................................................................................................................................................181D Review of Summer Flounder Assessments......................................................................................................................................................197

Chapter One

Executive Summary

* * *

Marine fish are important as a source of food, an item of commerce, the focus of recreational opportunity, and an element of cultural tradition in the United States and worldwide. Data from marine fisheries can contribute to our understanding of the marine environment and how humans relate to and use living marine resources. A comprehensive understanding of the problems currently challenging marine fisheries science and management requires consideration of both the biological and human dimensions of the fishery management process.

The dynamics of marine fish populations are affected directly by climate change, habitat availability, and water quality, but also are affected by human-influenced factors such as fishing and environmental degradation. In turn, human fishing practices are affected by the dynamics of the marine ecosystem and fluctuations in fish abundance. Thus, a complex relationship exists between fish and fishermen that must be maintained to foster the existence of both. At the intersection of these complex interactions are fishery managers, who are required by the Magnuson-Stevens Fishery Conservation and Management Act of 1976 (the Magnuson-Stevens Act) to preserve both fish populations and the human harvesters who depend on these fish. Fisheries management requires high-quality observations and well-supported predictions about the status and dynamics of fish populations, and these will be influenced by and influence human activities. Stock assessment scientists, economists, and social scientists must work with managers to design appropriate methods to collect, manage, and use accurate and precise biological, economic, and social data to accomplish their management responsibilities.

Fisheries management responsibilities are shared among several partners in the United States. Most of the available information is collected and analyzed by the National Marine Fisheries Service (NMFS) in cooperation with state and interstate agencies. Some international fishery treaty organizations also collect and assess similar types of information. Eight regional fishery management councils formed pursuant to the Magnuson-Stevens Act work with interstate fishery commissions, treaty organizations, and states to implement fisheries management based on "best scientific information available" (required by National Standard 2 of the Magnuson-Stevens Act). Commercial and recreational fishermen participate to varying degrees in different fisheries by helping NMFS collect data. Participants in fisheries management often refer to fishery-independent data (collected by a resource agency, independent from fishing activities and using scientific sampling methods) and fishery-dependent data (measures of directed commercial and recreational fishing activity).

ORIGIN OF STUDY AND COMMITTEE APPROACH

This study reflects NMFS' desire to have the National Research Council assess methods for improving data for stock assessments and fisheries management, and a more specific interest by Congress to have the summer flounder stock assessments reviewed. The two objectives formed the two parts of this study.

Congress requested a one-time study of summer flounder stock assessments by the National Academy of Sciences as part of a conference report that accompanied the Departments of Commerce, Justice, and State, and the Judiciary and Related Appropriations Act of 1998 (PL 105-119). The following statement of task was developed to make the committee's work more useful nationally and to address the issue of data quality, which the NRC (1998a) identified as a major factor in the performance of stock assessment models:

This study will evaluate the use of data in fish stock assessments and fishery management, including a variety of issues that range from those specific to summer flounder to more generic topics of data use for assessments of marine fish stocks. These issues will include methods of commercial data collection; accuracy and precision of fishery-independent surveys; institutional arrangements for data collection, analysis, and sharing among state and federal agencies; and appropriateness of data quality control procedures.

The congressional request to review the summer flounder assessments resulted from industry concern that NMFS had underestimated summer flounder stock size. Such a review also serves as an example of how fisheries data are used to provide assessment advice in general, how the quality of the data may affect the advice, and how public perceptions of data and assessments can affect their acceptance. Thus, the report first reviews the 1996 and 1999 assessments of summer flounder and then uses the insights this review provides to help develop ideas on the appropriate collection of fisheries data more generally. Of course, not all stocks are distributed, exploited, or managed in the same way as summer flounder, nor are they all assessed with similar data sets. For example, groundfish in East Coast fisheries (including summer flounder) are sampled more frequently than fish in other regions, so it is important to recognize that summer flounder data are more extensive than those for many other species on the East Coast and fish species from other regions. Some species on the U.S. West Coast are surveyed only once every three years, whereas some U.S. fish stocks are not surveyed at all. Data requirements may be different for other species, but a practical example provided by the summer flounder fishery provides insight and force to the committee's broader recommendations later in the report.

Evaluation of the Summer Flounder Assessments

The summer flounder fishery was used as a case study for broader data issues of greater interest to NMFS. Summer flounder is a particularly appropriate focus of a case study because this species supports a fishery that spans the state waters from Maine to North Carolina together with the U.S. exclusive economic zone adjacent to the waters of these states. This area is targeted by both commercial and recreational fishermen, and has an abundance of data available for assessments. The committee fully reviewed the summer flounder stock assessments of 1996 and 1999 and held public meetings to learn the concerns of commercial fishermen, recreational fishermen, and environmental advocacy groups related to the summer flounder assessments. The committee evaluated the summer flounder assessments using different stock assessment models as a means to explore issues related to the summer flounder data.

Broader Data Collection and Analysis Issues

The broader issue of the need to improve the quality of data used in stock assessment was highlighted in the NRC report entitled Improving Fish Stock Assessments (NRC, 1998a), which showed that the quality of data used in five stock assessment models was more important than the particular model used. The present committee examined all forms of data available for stock assessments and fisheries management, including data from fishery-independent surveys, fishery- dependent data from commercial and recreational fishermen, and auxiliary data collected from a variety of other sources. The committee also examined traditional and new methods for collecting data, and discussed the current state of data management and several new developments in data collection and management.

FINDINGS AND RECOMMENDATIONS

Review of Summer Flounder Stock Assessments

Three analyses of summer flounder data by three individuals using three stock assessment models yielded the same general trends indicated by the 1999 NMFS assessment. These analyses showed that the spawning stock biomass had recovered substantially from a trough in the early 1990s, and that fishing mortality dropped substantially in the same period. The committee believes that both changes are probably due to strict management measures implemented in 1992.

The models yielded some differences in predictions that are relevant to summer flounder management. These differences probably arose because there are assumptions in each modeling method that are not explicitly stated, but that affect model results. Thus, it is especially important to document all assumptions made within these complex models-whether explicit or implicit.

First, the model predictions of spawning stock biomass vary somewhat over time, especially in the most recent years. Some models indicate that the biomass has peaked and is falling again. This variability in the estimates of summer flounder biomass should be considered in managing the fishery, taking into account the range of possible spawning stock estimates from the models. All model biomass estimates are lower than the NMFS estimate.

Second, estimated fishing mortality rates varied greatly among the models. This result has implications for fishery managers in terms of how well they may be able to meet quantitative management targets, called biological reference points, based on fishing mortality rates. In the last year of the series, each method produced almost the same estimate of fishing mortality, all of which are above the fisheries management target level of fishing mortality (0.24 [year.sup.-1]). The bottom-line conclusion of the committee's review of the summer flounder assessments is that the managers responsible for this species should be aware of the uncertainty that arises from the choice of model and should manage more cautiously (e.g., reducing fishing mortality) in the presence of such uncertainty. This will generally require that they be somewhat more protective of fish stocks. Stock assessment scientists responsible for summer flounder should investigate how differences among model estimates arise and whether such differences indicate changes needed in the models or assumptions used.

These model runs were performed using most of the explicit assumptions used in the NMFS analyses, and assumed that NMFS and state surveys accurately portray the summer flounder population. But, what if the assumptions used by NMFS are incorrect? The committee addressed this possibility by analyzing the summer flounder data using the virtual population analysis method a number of times, changing single assumptions for different runs. Through these model runs, the committee came to the following conclusions:

There is little direct evidence for the existence of a large number of unsurveyed large summer flounder, as claimed by some in the industry. Nevertheless, it is plausible that NMFS survey methods could miss such fish if larger fish are less susceptible than smaller fish to capture using NMFS trawl gear and methods. The committee demonstrated that this is an important issue in terms of the fishing mortality targets and total allowable catch, and suggested ways that NMFS could try to determine whether there are a significant number of unaccounted-for large summer flounder. If the NMFS surveys are less likely to catch larger fish than smaller fish, the previously documented size difference between female and male summer flounders will also need to be considered in assessments.

The age structure of the summer flounder population is important and its determination will require that NMFS and fishermen work cooperatively. The first stage should be joint trawling exercises by NMFS and commercial fishermen, using both traditional and adaptive sampling techniques, to test the effects of trawl gear and methods on catch. This would be the most direct approach. NMFS could also take additional, less direct steps, such as conducting egg surveys and tagging studies, but these actions could be more expensive and would take years to gather meaningful data. Observers could assist in tagging and recovering tags from fish.

Another major need in stock assessments for summer flounder is for NMFS and industry to improve reporting of the discard rate. Because of the effect of discards on estimation of biomass and fishing mortality rates, industry and NMFS need to work together to devise means to encourage accurate reporting. One short-term solution would be to increase observer coverage to a high enough level to provide statistically meaningful estimates of discards. This could be accomplished by allowing fishermen on observed trips to catch more flounder to pay observer costs.

Recreational fishing for summer flounder has been contentious during the past several years because of catch overruns in the recreational portion of the fishery. Recreational fisheries have been allotted 40 percent of the total allowable catch, but have taken more than 50 percent in the past two to three years. In part, this has occurred because the population of young fish, those more likely caught by inshore anglers, has rebounded in response to strict management controls. Because recreational data have a several-month lag time between collection and availability for management, overfishing can occur before fishery managers are aware of the problem. This problem is not unique to summer flounder; it is shared with most fisheries that have a significant recreational sector. Effective management cannot be achieved if only commercial fishermen are regulated strictly, while little control is exerted over recreational catches. Anglers, states, regional councils, and NMFS should work together to solve this particularly difficult problem. The ultimate goal should be data collection and management systems that allow in-season management of summer flounder fisheries, if this goal can be achieved cost effectively. In the absence of such a capability, the populations of summer flounder can be sustained only by more conservative management of recreational fisheries.

The actions recommended here may seem too extensive to be justified on the basis of the benefits of better data for the summer flounder fishery alone, particularly considering that NMFS must collect data for many other species. The premise of this study, however, is that lessons from the examination of the summer flounder data and assessments can be applied more broadly because summer flounder stocks, like those of many other groundfish species, are subject to both commercial and recreational fishing and cross legal boundaries of many states and the federal exclusive economic zone. The committee recommends that NMFS and the regional councils implement the recommendations of this report as a test of new ways of cooperating with commercial and recreational fishermen to improve both data quality and acceptance of stock assessment results.

Broader Data Collection, Use, and Management

The committee believes that all the participants in fisheries management should take actions to improve the collection, management, and use of fisheries data. The committee developed the following recommendations to Congress, NMFS, the regional councils, interstate commissions, and commercial and recreational fishermen with the objective of improving fisheries data and thereby fisheries management.

Recommendations to Congress

The U.S. Congress affects fisheries science and policy in two primary ways. First, Congress is the architect of the centerpiece of federal fisheries legislation, the Magnuson-Stevens Act. At present, Congress is formulating legislation to reauthorize the Magnuson-Stevens Act, whose funding authority expires on October 1, 2000. The committee recommends several ways in which the reauthorization could improve fisheries data collection, management, and use in the United States.

Second, Congress appropriates funding for NMFS, the regional councils, and interstate and international commissions to carry out their activities related to fisheries science and management. The committee highlights several items for which additional funding could improve fisheries data collection, management, and use and, consequently, fisheries management. Funding for more capable research vessels and for planning a Fisheries Information System are recent examples of positive congressional steps toward modernization of fisheries data.

(Continues...)

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