A Systems Approach to Fisheries Science and Management: Beyond Management Strategy Evaluation

INTERNATIONAL COUNCIL FOR ICES CM 2010/R:02 THE EXPLORATION OF THE SEA Delivering more science with fewer resources A Systems Approach to Fisheries Science and Management: beyond management strategy evaluation Steve Cadrin, Brian Rothschild, Azure Westwood, Cate O’Keefe, Greg DeCelles, Emily Keiley and Dan Georgianna University of Massachusetts, School for Marine Science and Technology, USA Abstract: Operations research is typically applied to fisheries science in the form of either adaptive management or ‘management strategy evaluation.’ Adaptive management implements alternative approaches to address specific problems and monitors effectiveness of actions. Management strategy evaluation uses an operating model to simulate fishery and survey data; the data are analyzed by a stock assessment model; assessment results are used for pre‐defined management decisions; management decisions iteratively feed‐back on the operating model; and performance of the harvest control rule is evaluated with respect to stated objectives. A systems approach to fisheries science and management combines the flexibility of adaptive management with the quantitative simulation of management strategy evaluation to provide a more holistic approach in which scientific and administrative investments can be optimized and objectives can be iteratively refined. The last two decades of global fishery management illustrate a series of evolving objectives: 1) avoiding recruitment overfishing; 2) incorporating uncertainty in a precautionary approach; 3) achieving maximum long‐term yield by avoiding growth overfishing; 4) achieving optimal yield for multiple socioeconomic utilities; and 5) considering ecosystem approaches and utilities. Despite the substantial changes in system requirements associated with these developments, investments in fishery science have remained remarkably static, continuing conventions for fishery sampling and resource surveys that were designed in the context of past objectives and obsolete technologies. Application of new technologies are typically evaluated and implemented within the narrow objectives of each program rather than in the broader context of related programs and performance of the entire system. A systems approach to fisheries science and management offers a more strategic tool for maximizing investments in fisheries beyond the evaluation of alternative harvest rules. Keywords: systems analysis, operations research, management strategy evaluation Steven X. Cadrin, University of Massachusetts School for Marine Science & Technology, 200 Mill Road, Fairhaven MA 02719 U.S.A. tel: +001 508 910 6358, email: [email protected] 1 INTRODUCTION Fishery management systems attempt to achieve many objectives with modest operational budgets, so effective fishery science must optimize multiple utilities within ecological and societal constraints. When the environment changes (e.g., climate) or societal values change (e.g., international environmental policies), fishery science and management systems must respond to achieve optimal allocation of limited resources. Systems analysis is an approach that considers all system components and their linkages to evaluate performance toward meeting objectives, identify areas that need improvement, optimize allocation of resources, and even re‐evaluate objectives (Quade and Boucher 1968). Historical and recent episodes in global fishery management show how objectives evolve. For example, the ICES advisory system illustrates a series of successively refined objectives and increasing demands from monitoring programs, routine stock assessments and fishery management: Optimum yield – prior to the 1980s, ICES advice was based on maximizing yield per recruit, by recommending that fishing mortality (F) be equal to Fmax or F0.1 (Lassen 1999). Yield per recruit analysis requires relatively simple life history information (size at age or growth parameters) and size or age selectivity of the fishery (Thompson and Bell 1934, Beverton and Holt 1957). Stock assessments were primarily required to provide estimates of F, which could be achieved with samples of fishery size or age composition. Management involved size limits for landing fish or gear restrictions, and limiting fishing effort. Avoiding recruitment overfishing – In the 1980s, the basis of ICES advice was focused on ‘safe biological limits’ determined by the minimum biologically acceptable level of stock size and fishing mortality (Serchuk and Granger 1992). Safe biological limits were typically defined according to stock‐recruitment estimates and associated F that would allow replacement (Fmed; Sissenwine and Shepherd 1987). Stock assessment was required to provide estimates of a time series of F, stock size (e.g., spawning biomass) and recruitment (e.g., age‐1 abundance), which typically involved a time series of fishery catch‐at‐age estimates as well as indices of relative abundance (fishery catch rates or standardized surveys). Fishery management needed to include rebuilding plans to conserve adequate spawning biomass and associated mid‐term projections. A precautionary approach – In the late 1990s, uncertainty in limit reference points was incorporated into the ICES advisory framework in the form of precautionary reference points (Fpa and Bpa; ICES 1998). The precautionary approach required a more formal statistical model to synthesize fishery and survey information and provide measures of precision. The focus on uncertainty also required evaluation of all potential sources of bias (e.g., discarded catch, catchability of abundance indicators, stock identity), which in turn demanded more of fishery monitoring, resource surveys and analytical methods. Fishery management needed to consider risk tolerance. Achieving maximum long‐term yield – For the past few years, ICES advice has considered long‐ term yield, and 2010 advice is based on achieving maximum sustainable yield (MSY; ICES 2010c). 2 A MSY‐based advisory system requires a broader understanding of stock and fishery dynamics, often needing to extrapolate beyond observed time series of F and stock size (Brodziak et al. 2008). Fishery management now relies heavily on long‐term projections. Ecosystem conservation – A parallel development that is independent to the refinement of single‐species advice is more integrated ecosystem‐based advice (ICES 2009a). Implementing integrated ecosystem assessments requires monitoring all biological components of the system, some of which have not been traditionally monitored by fishery science and management systems (ICES 2010a). Management is based on multiple indicators and multiple sets of stakeholders. Optimal yield for socioeconomic utilities – In addition to requiring expanded consideration of natural components of the system, integrated ecosystem assessment also involves integrated management of all human impacts (ICES 2009c). Management of fisheries in the context of other human uses requires a broadening of the definition of optimum yield, and an investment in social sciences to confront societal tradeoffs (Hilborn 2007). These successively refined objectives in the ICES advisory system reflect global trends in fisheries science and management. Each new set of objectives influences a wide range of research and monitoring programs that produce data for stock assessment, and they present substantial new challenges for fishery management programs. Each successive change can be viewed as an adaptive revision to address previous system failures. For example, maximizing yield‐per‐recruit ignored the negative feedback of F on stock size, recruitment and total yield, so advice was re‐focused on avoiding recruitment overfishing. The focus on avoiding recruitment overfishing ignored the gains that could be achieved by optimizing long‐term yield, etc. STRATEGIC ANALYSES IN FISHERIES SCIENCE Despite the fundamental changes in fishery management objectives that have occurred in the last three decades, allocations of investments in fishery science have remained remarkably static. Traditional monitoring and management programs have been continued, rather than revising the system design to meet the new system requirements. Applications of new technologies are usually slow to develop. When new technologies are applied, they tend to address relatively narrow program objectives, rather than system requirements. Strategic analyses are needed to support decisions about investments and system design (e.g., Rothschild 1973). In fisheries science, strategic analysis of fisheries systems typically takes the form of adaptive management or management strategy evaluation. Adaptive management (Walters 1986) implements alternative strategies and evaluates how well they meet objectives. The adaptive management cycle (Figure 1) includes: 1) definitions of objectives, including communication with all stakeholders; 2) system description, including subsystems, components and linkages; 3) identification of system failures, including feedback from stakeholders; 4) identification of possible solutions from brainstorming; 5) implementation of alternative system configurations; and 6) monitoring system response (Jones 2005). Although identification of failures, 3 development of alternatives, and implementation of new strategies are common, problems and solutions are often not considered within the entire system, and evaluating effectiveness of alternatives for meeting objectives is rare. Figure 1. The adaptive management cycle (from Jones 2005). Management strategy evaluation is

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