Robert McKelvey

Specialist and Generalist: Roles for Coping with Variability

Abstract Two behavior patterns of fishermen, specialist and generalist, are evaluated as ways of coping with market and natural variability. Changes in these behaviors predicted by an analytical model are evaluated against data from several fisheries. The predictions and the data suggest that a mix of specialist and generalist fishing behavior is a way of coping with unpredictability. Management usually regards fishing behavior as homogeneous; as a result, many management rules discriminate against one type of behavior or the other.

The fishery in a fluctuating environment: Coexistence of specialist and generalist fishing vessels in a multipurpose fleet

Abstract The fishery is a prime example of a common property renewable resource industry. A second prominent feature is the extreme variability of its environment, both biologic and economic. Traditionally fishing vessels have harvested a single species or aggregation, but now powerful multipurpose vessels have been introduced which switch targets as opportunities arise. These vessels represent an adaptation to the fluctuating environment: they give up efficiency of specialized operation for flexibility under changing conditions. We analyze, from the point of view of economic efficiency, the common property operation of a mixed fleet of generalist and specialist fishing vessels in a fluctuating environment.

Decentralized regulation of a common property renewable resource industry with irreversible investment

Abstract The effectiveness of output controls for rationalizing a common property renewable resource has been called into question by the theoretical work of J. R. Gould [Economica, Nov., 383–402 (1972)]. A proper examination of this question requires an intertemporal analysis, one that takes into account that asymmetries between persistent factors of production (“immaleable capital”) and factors that are instantaneously consumed (“labor” or ldharvest effort”). We present here a nonlinear intertemporal model of a renewable resource industry, under conditions of irreversible capital investment, and undertake to analyze its dynamics, both at open access and under centralized optimal management. We then examine the theoretical possibility of decentralized regulation by Pigouvian taxes, and reconsider the proposition of Gould.

Viability analysis of endangered species: a decision-theoretic perspective☆

Abstract The concept of population viability is probabilistic in nature, usually being expressed through such indicators as ‘expected extinction time’, or ‘probability of survival for 1000 years’. Such one-dimensional indicators might be adequate to characterize empirically-derived extinction risk in steady-state circumstances, such as in a long-established and undisturbed reserve. But they do not serve as well for evaluating viability in dynamically changing environments, nor for appraising the circumstantial evidence of risk provided by computer simulation of a stochastic population model. To characterize risk adequately in these circumstances requires describing a qualitative pattern of risk, sorting out short-term effects, due to initial population size and environmental state, from longer-term effects related to the character and quality of habitat. Furthermore, the relevant time-scales for the analysis depend upon the processes of change present in the habitat, including persistent effects from deliberate or inadvertent anthropogenic habitat manipulation. In the present study, alternative extinction risk indices and sustainability profiles are suggested, appropriate for formulating a risk management strategy in a dynamically changing environment. The concepts presented are applied to the problem of viability assessment of the endangered northern spotted owl, in the harvested temperate rainforest landscape of the U.S. Pacific Northwest.

Fur Seal and Blue Whale: The Bioeconomics of Extinction

Common property exploitation repeatedly has been implicated in instances of mismanagement of marine biological resources, resulting in depletion, even exhaustion, of stocks, and in dissipation of the economic benefits that the harvest might entail. Here I shall re-examine historical patterns in the competitive exploitation of two marine mammals, examining the interplay between common property harvest practices and inertial effects that result, among other things, from irreversible capital investment (“sunk capital”) in the harvesting industry. I find that common property exploitation tends to exaggerate the swings and overshoots that inertial features introduce into the temporal pattern of harvesting, leading to an excessive buildup of capital capacity, followed by an excessive depletion of the resource stock. Under some conditions these exaggerated swings can result in stock extinctions which optimal management might have avoided. The formal model is set up as a differential game, and analyzed by control theory methods.

The Effects of Incomplete Information in Stochastic Common-Stock Harvesting Games

Here the dynamic fishery harvesting game is generalized to a stochastic environment in order to examine the implications of incomplete and asymmetric information. The main emphasis is on a split stream version of the game: At the beginning of each harvest season the initial fish stock (or “recruitment”) divides into two streams, each one accessible to harvest by just one of the two competing fishing fleets. The fleets simultaneously harvest down their streams, achieving net seasonal payoffs for the catch. After harvest, the residual sub-stocks reunite to form the broodstock for the subsequent generation. The strength of this subsequent generation is determined by a specified “stock-recruitment relation,” and the cycle repeats. In this cyclic process, both natural environmental factors (stream-split proportions and stock-recruitment relation) and economic factors (harvest costs and benefits) will incorporate Markovian stochastic elements. At the beginning of each season, both fleets know the current recruitment and also have some (generally incomplete or delayed, and often asymmetric) knowledge of the current values of the stochastic elements. The knowledge structure of each specific game version is held in common by the competitors. In the dynamic game each fleet sets its harvest policy with the objective of maximizing the expected discounted sum of seasonal payoffs, and conditional on the extent of its current knowledge and of the anticipated policy of its competitor.

Common Property and the Conservation of Natural Resources

Biological resource modeling is a blend of population biology and resource economics. The choice of the word “resource” suggests that the emphasis is on use (presumably conservative and efficient use), rather than on permanent preservation.

Groundwater-Based Agriculture in the Arid American West: Modeling the Transition to a Steady-State Renewable Resource Economy

In the years since World War II, a flourishing large-scale irrigation agriculture has developed in the arid American West, based on the pumping of groundwater from vast underground pools. Water withdrawals, far in excess of natural recharge, had seemed to make inevitable a cyclic “bust” following the present agricultural “boom”, much as happened in the earlier gold-silver-copper “rush” in the Mountain West. However, remarkable technological advances, in irrigation techniques and in the development of genetically-adapted dryland crops, now offer at least the hope of a “soft” transition to a steady-state renewable-resource based economy. Whether this occurs, or whether on the other hand the marvelous technological gains are dissipated away and only briefly delay agricultural collapse in this harsh and erratic climate, may depend on whether farmers and agricultural planners continue to ignore basic economic institutional forces: the destructive effects of uncoordinated common property exploitation of water, compounded by the high degree of irreversibility in capital investment in pumping and distribution systems and in regional infrastructure. These issues are explored with the aid of simple mathematical models.

Analyzing the Harvesting Game or Why are There So Many Kinds of Fishing Vessels in the Fleet

Harvesting of commercial marine fish stocks can be thought of as a game, with free entry of all kinds of players (the fishing vessels), and freedom for these vessels to choose their target species, and to switch targets at will. The result is a complicated and confusing mix of vessel types and activities. One is led to seek general principles, with which to bring some order into this chaos.