Decision-Making Under Uncertainty

Transcription

1 1. Correspondence (January 29-31, 2019) M #5a Decision-Making Under Uncertainty (A Report from the National Aquarium) Steve Cadrin, Panel Member University of Massachusetts Dartmouth School for Marine Science and Technology January New England Fishery Management Council Objectives to understand sources and treatment of uncertainty advance best practices for reducing or managing with uncertainties in fisheries management systems 1

2 Expert Panel Eric Schwaab, National Aquarium (Chair) Dr. Steven Cadrin, University of Massachusetts Dartmouth John Henderschedt, Fisheries Leadership and Sustainability Forum Dr. Pamela Mace, New Zealand Ministry for Primary Industries Dr. Steven Murawski, University of South Florida Dr. Joseph Powers, Louisiana State University Dr. Andre Punt, University of Washington Dr. Victor Restrepo, International Seafood Sustainability Foundation Dr. Richard Methot, NOAA Fisheries (special advisor) Themes Identifying and Communicating Sources and Treatments of Uncertainty Best Practices for Reducing Uncertainty Managing Fisheries in the Context of Environmental Change Risk-Based Management Decisions: Prioritizing Responses to Uncertainty 2

3 Identifying Uncertainty Recommendation 1: Clearly communicate sources, treatment and impacts of uncertainty Sources of Uncertainty Scientific Sources Data measurement error Model estimation error Ecosystem process error Management Sources implementation error Uncertainty in Data (Measurement Error) Fishery Monitoring (commercial and recreational landings and discards) Accuracy and precision of catch estimates and age/size composition by stock Improved with better sampling (e.g., observer coverage, electronic monitoring) Resource Monitoring Accuracy and precision of stock indices and age/size composition Improved with survey design, greater frequency, sampling ratio and technology 3

4 Uncertainty in Models (Estimation Error) Model assumptions: natural mortality, selectivity, recruitment, maturity Precision can be evaluated by fit to the data and accounted for in buffers between the overfishing limit (OFL) and acceptable biological catch (ABC) Accuracy can be evaluated through simulation Estimation error can be reduced by best practices in modeling field estimates of predation, consumption, selectivity and maturity Uncertainty in the Ecosystem (Process Error) Changes in productivity (natural mortality, growth, recruitment) Re-evaluation of reference points (maximum sustainable yield) may be needed Process errors can be reduced by understanding the system and ecosystem approaches 4

5 Management Uncertainty (Implementation Error) Imprecise or biased catch monitoring (misreporting, misrepresentative samples) Annual Catch Target (ACT) can be less than the Annual Catch Limit (ACL) Implementation error can be reduced by in-season monitoring and enforcement. Identifying Uncertainty Recommendation 2: Define stakeholder roles and responsibilities Scientists and managers should work collaboratively to in the fisheries science and management process so that they understand and their responsibilities, and interactions relating to uncertainty. 5

6 Identifying Uncertainty Annual Catch limits are based on short-term projections, including the overfishing limit and imprecision. Fishery management plans involve longer-term objectives and strategies. Fisheries Ecosystem Plans and Integrated Ecosystem Assessments provide longterm information on the marine climate. Communicating Uncertainty Similar to meteorologists predictions of weather, fishery scientists predict fish abundance Both predict future events and evaluate risks and consequences for affected populations. Meteorologists have the advantage of eventually knowing the true outcomes. Most people understand that weather forecasts are uncertain and account for uncertainties in their decisions. 6

7 Reducing Uncertainty Strategic allocation of investments in fisheries dependent and independent data, modeling and assessment processes can reduce uncertainty. Recommendation 3: evaluate benefits and costs of additional research, alternative investments in data, or application of new technologies and methods for stock assessment. A prioritization plan should focus resources to reduce uncertainty and risk. Management Strategy Evaluation (MSE) can be particularly useful in this process. Recommendation 4: Congress and the Administration should support the Magnuson-Stevens Act with greater investments in the science needed to achieve the goals of the Act. Particular attention is needed for recreational fisheries and data-limited situations. Reducing Uncertainty Recommendation 5: Prioritize improved catch accounting When the benefits outweigh the costs, managers should prioritize accurate catch accounting for all managed fisheries. Recommendation 6: Focus on cooperative research Managers and policy makers should only divert existing resources to cooperative research in cases where cooperative approaches are cost-neutral or beneficial. Recommendation 7: Explore new technologies Application of advanced technologies can provide cost-effective improvements in collection of fisheries-dependent and independent data. 7

8 Reducing Uncertainty Recommendation 8: Address frequency of stock assessments Adopt clear check points and sets of indicators that trigger use of new information in advance of a complete stock assessment Recommendation 9: Evaluate methodologies for data poor stocks Considering Environmental Change Recommendation 10: Expand fisheries oceanography research. Understand mechanisms, trends and effects Recommendation 11: Integrate ecosystem science into stock assessments Increase emphasis on broader ecosystem trends and their effects on fisheries science and management decisions. Failure to adapt models and strategies to account for climate change may undermine fishery performance. Recommendation 12: Prepare for environmental shifts through education, control rules and reference points prepare for a potential environmental or ecosystem shift by educating all participants about the possibility and the potential need to amend reference points and other aspects of control rules or management measures as stock productivity changes. 8

9 Considering Environmental Change Councils that have more explicit processes and tools in place to explore and incorporate larger system uncertainties have been more proactive in considering and responding to longer-term challenges such as ecosystem variability. Ecosystem status reports should be used to incorporate multi-species interactions and environmental conditions into assessments and management decisions. The next step would be to use this information to change reference points and other aspects of control rules and resulting management schemes. Sea Surface Temperature (C) Shifting Distribtutions 9

10 Ecosystem Approaches Comprehensive Fisheries Oceanography Program Ecosystem Consideration Reports Maximum ABC Reference Point Allocations Based on Distribution Harvest Control Rules that Incorporate Environmental Change Risk-Based Management Recommendation 13: Adopt explicit risk policies Incorporate considerations of risk (likelihood and severity of consequences) into fisheries management actions and explicitly communicate those risks. Many ABC control rules include an implicit risk tolerance, but other risks in the fisheries management system are confronted in a much more ad hoc manner. Recommendation 14: Adopt formal procedures to communicate risk Adopt explicit risk policies based on stock vulnerability, availability of data, and the perspectives of fishery participants (e.g., stability of the fishery from year to year). 10

11 Risk-Based Management Tiered approach to Acceptable Biological Catch (ABC) based on availability of data to assess risk Structured ways to respond to risk outside of the ABC process Decision tables to communicate risk NEFSC 2012 Management Strategy Evaluation Recommendation 15: Test control rules for robustness to uncertainty Management Strategy Evaluation workshops improved communication about uncertainty MSE reduced impacts to stakeholders, considered effects of environmental change, selected preferred management option Harvest control rules can incorporate environmental effects, etc. 11

12 Themes Identifying and Communicating Sources and Treatments of Uncertainty Best Practices for Reducing Uncertainty Managing Fisheries in the Context of Environmental Change Risk-Based Management Decisions: Prioritizing Responses to Uncertainty 12