Climate Change, Predator-Prey-Harvesting (PPH) and Policy Cycle Management (PCM) Models, and Sustainable Fisheries in Changing Supply Conditions

By Alexander Woodcock and Allan Falconer.

Published by The International Journal of Climate Change: Impacts and Responses

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Article: Print $US10.00
Article: Electronic $US5.00

The 2009 World Bank study “The Costs to Developing Countries of Adapting to Climate Change: New Methods and Estimates” clearly states that the costs of Climate Change to global fisheries may reach an estimated US$ 9.64 billion in the year 2050. The estimated cost to developing countries could be as high as US$ 7 billion. These revenue projections reflect climate induced changes in ocean ecology and their impact on fish stocks. The complex relationships involved include management practices and therefore offer the potential for actual recovery in fish stocks if governments and/or managers implement appropriate controls on fishing activity. Worm et al. in Rebuilding Global Fisheries (2009) describe how merging different management approaches can facilitate the rebuilding of fisheries in diverse locations.

An adaptable harvesting policy for fish stocks responding to climate change and other stressors is clearly needed. Meeting this need appears possible through integration of a prototype policy cycle model (Woodcock, 2008) with prototype density-dependent growth and predator-prey harvesting models implemented in systems dynamics software. The policy cycle model simulates the major processes in the development and implementation of public policies (Lester and Stewart, 2000 and Anderson, 2003, for example).

Predator and prey populations may exhibit sustained oscillations, which can be altered by changing the rate of harvesting of the prey species in the models. There is room to add additional relationships with chlorophyll levels, ocean temperatures, and bait fish activity in order to create clearer links between the expected changes in ocean ecology and the predicted response of fish stocks. It appears that the working models of the population dynamics and policy cycle permit an informed manager to anticipate population behavior and avoid catastrophe.

The policy cycle model shows that rapid events can affect timely changes in harvesting rates while slower events impede the recovery process of a fishery under climate change and harvesting stresses. This echoes other applications of the policy cycle model to military conflict and causes of societal violence (Woodcock, Christensson, and Dockery, 2009). Those models have demonstrated that slow changes in policy responding to military or societal challenges can lead to the undermining of friendly forces or to increased levels of societal violence. Based on this prototype systems-dynamics-based policy-cycle-models have been implemented to examine the impact of harvesting levels and policy dynamics on the availability of fish stocks.

Results of a series of preliminary model-based experiments involving responses to notional fish growth and harvesting are presented and discussed in the context of the harvesting-related behavior of actual fisheries. A brief look at the Eastern Canadian fishery over the period 1950-2000 provides some illustration of the concept. Application of the model to the Tuna fishery of the Warm Pool North-East of Australia (a large marine ecosystem), and specifically the use of the model in the management of the North-Eastern Australian Yellow Fin Tuna fishery was considered. These activities provide a basis for defining adaptable harvesting policies that would promote self-sustaining fisheries in fragile environments.

Keywords: Fisheries Management, Climate Change Impacts Ocean Fish Stocks, Policy-related Management Models, Predator-Prey Models, Managing Sustainable Fish Stocks in a Changing Environment

The International Journal of Climate Change: Impacts and Responses, Volume 3, Issue 1, pp.1-30. Article: Print (Spiral Bound). Article: Electronic (PDF File; 1.100MB).

Dr. Alexander Woodcock

Affiliate Professor, The School of Public Policy, George Mason University, Fairfax, Virginia, USA

Alexander Woodcock Ph.D. is a consultant to several US government entities and an Affiliate Professor in the School of Public Policy at George Mason University (GMU). Since 1980 he has specialized in development of small agile computer models that provide new insight into the dynamical behavior of complicated societal systems. He led development of the Deployable Exercise Support System (DEXES) for US Southern Command. DEXES has been used to support over 15 humanitarian assistance and disaster relief exercises in South and Central America. He also led development of the Strategic Management System (STRATMAS®) for the US Joint Staff and the Supreme Commander of Swedish Defence. STRATMAS® has been used to support international exercises on Afghanistan and Iraq. He is the author of Assessing Iraq’s Future which has been published by the Royal Swedish Academy of War Sciences. He is the Chair and Proceedings Editor for the Cornwallis Group, which is involved in analysis of peace operations and related areas. He was a Senior Research Professor at GMU and Chief Scientist and Vice President at BAE Systems-Portal Solutions. He is a Foreign Member of the Royal Swedish Academy of War Sciences and a Fellow of the Royal Society of Medicine.

Prof. Allan Falconer

Professor of Geography and Director of Corporate Engagement, Office of the Vice-President for Research and Economic Development, George Mason University, Fairfax, Virginia, USA

Allan Falconer is Professor of Geography at George Mason University and former Chair of the Department. He has worked with the application of geospatial technology to natural resources management and mapping since the ERTS-1 (Landsat) simulation studies of 1970. He has been employed by governments, businesses and universities around the world to work in environments ranging from deserts (Kalahari, Mojave, Sahara and South Australian) to oceans (Arctic, Atlantic, Indian and Pacific). From 1978-1989 he was a member of the project team establishing the Regional Remote Sensing Facility for East and Southern Africa where he advised on natural resources applications of remote sensing in that region. He has designed and directed geospatial projects for US Federal Agencies (DoD, Department of Interior, USDA, USAID, NASA) and been a consultant to UN/FAO, UNECA, UNESCO, UNEP, UN-COPUOS and World Bank in many aspects of natural resources mapping and management. He is a Fellow of the Royal Geographical Society, the Remote Sensing and Photogrammetry Society and the American Society for Photogrammetry and Remote Sensing.


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