Colin Whitcomb Clark

• Ph.D. University of Washington, 1958
• University of British Columbia

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This article reviews the authors' earlier attempts to incorporate the theories of capital and investment into fisheries economics and argues that such dynamic analysis is now of immediate policy relevance. It also discusses some limitations to the earlier analysis and means of addressing them. It then goes on to point to two areas of potential futu...

We discuss the current global economic crisis as an analog of short-term harvesting of a biological resource, in which motives of short-term profit over-ride sustainability considerations.

Many natural resources that are not privately owned are exploited as common property. Important examples include ocean fisheries, the ocean itself, and the global atmosphere. Theory suggests that common-property resources will be overexploited in the sense that long-term conservation (investment) in the resource stock will be well below the socio-e...

We present a bioeconomic model, of an intermediate degree of complexity and realism, of the prawn fishery of the Gulf of Carpentaria and adjacent waters in Northern Australia. The model employs 21 parameters to describe the performance of two classes of vessels exploiting several stocks of prawns. The model predicts the number of vessels of each cl...

The problem of optimal regulation of a fishery is discussed. Of special interest is the problem of regulating an overexploited fishery by reducing effort to allow the fish population to build up to a suitable level.We first argue that the problem requires an economic analysis based on the concept of maximization of present value. From this concept...

A model of the commercial fishery, incorporating the microeconomic decisions of individual vessel operation, is developed and employed to predict the consequences of various methods of regulation, including: (i) total catch quotas; (ii) vessel licenses; (iii) taxes on catch (or effort); (iv) allocated catch (or effort) quotas. Among the principal p...

A debate is emerging over the extent to which privatization of fishery resources is socially desirable. The "pessimists" argue that there are strict limits to socially optimal privatization of such resources. The "optimists" maintain that there are no effective limits to privatization and that the decades old fear that privatization could, in some...

A debate is emerging over the extent to which privatization of fishery resources is socially desirable. The "pessimists" argue that there are strict limits to socially optimal privatization of such resources. The "optimists" maintain that there are no effective limits to privatization and that the decades old fear that privatization could, in some...

Marine fisheries throughout the world continued to be severely overexploited throughout the 20th century and beyond. Even under intensive ‘scientific’ management many important fisheries have collapsed, some never to recover. Vast overcapacity of fishing fleets is also widespread. Both outcomes can be attributed to the common-pool aspect of fishery...

The public perception of fisheries is that they are in crisis and have been for some time. Numerous scientific and popular articles have pointed to the failures of fisheries management that have caused this crisis. These are widely accepted to be overcapacity in fishing fleets, a failure to take the ecosystem effects of fishing into account, and a...

This paper deals with the time consistency problem associated with buyback schemes, arising from the fact that the schemes may be anticipated by vessel owners. After reviewing and elaborating upon the key results of our recently published article on buybacks and limited-entry programs, we discuss the consequences of combining buybacks with ITQ sche...

Members of breeding groups face conflicts over parental effort when balancing antipredatory vigilance and feeding. Empirical evidence has shown disparate responses to manipulations of parental effort. We develop a model in which we determine the evolutionarily stable effort of partners given their body conditions, allowing the benefits of shared ca...

The world's marine fisheries are in trouble, as a direct result of overfishing and the overcapacity of fishing fleets. Despite intensive management efforts, the problems still persist in many areas, resulting in many fisheries being neither sustainable nor profitable. Using bio-economic models of commercial fisheries, this book demonstrates that ne...

Experiments indicating learning in the context of courtship in fruit flies challenge the prevailing views that male insects are either indiscriminate or rely on innate rules for courtship. We investigated the conditions favouring learning during courtship in insects by using a model that compared a learning strategy to two alternatives, indiscrimin...

Many fisheries management systems, even when based on apparently sound science, have failed to prevent severe overfishing. And even when successful in this sense, such systems have frequently resulted in a large degree of excess fishing capacity. The reason for these failures can often be found in a lack of consideration of the economic incentives...

The world's marine fisheries are in trouble, as a direct result of overfishing and the overcapacity of fishing fleets. Despite intensive management efforts, the problems still persist in many areas, resulting in many fisheries being neither sustainable nor profitable. Using bio-economic models of commercial fisheries, this book demonstrates that ne...

The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries: inapprop...

The failures of traditional target-species management have led many to propose an ecosystem approach to fisheries to promote sustainability. The ecosystem approach is necessary, especially to account for fishery-ecosystem interactions, but by itself is not sufficient to address two important factors contributing to unsustainable fisheries —inapprop...

Most fisheries subsidies, which on a worldwide scale are immense, are probably detrimental to resource conservation. However, payments used to buy out excess fishing capacity are often represented as useful subsidies, on the grounds that overcapacity encourages overfishing and causes economic waste. Some commentators, on the other hand, assert that...

Using examples from more than a dozen fisheries, we highlight the failures of ‘command control’ management and show that approaches that empower fishers with the incentives and the mandate to be co-custodians of the marine environment can promote sustainability. Evidence is provided that where harvesters share well-defined management responsibiliti...

This paper shows that increases in the minimum wage rate can have ambiguous effects on the working hours and welfare of employed workers in competitive labor markets. The reason is that employers may not comply with the minimum wage legislation and instead pay a lower subminimum wage rate. If workers are risk neutral, we prove that working hours an...

Limited attention may constrain animal behavior in situations in which the rate of relevant information exceeds the threshold processing capacity of the brain. In the present study, we examine why attention is limited by quantifying how attention affects the ubiquitous problem of balancing foraging and antipredator activity. We analyze how a given...

Overcapacity of marine fishing fleets is common everywhere, leading to recommendations for the reduction of capacity. One approach, vessel buybacks, has a mixed record of success, as the remaining, licensed vessels tend over time to attain increased fishing power as a result of 'capital stuffing'. The present paper analyzes the economics of overcap...

Many food hoarding animals live in small groups structured by rank. The presence of conspecifics in the hoarding area increases the risk of losing stored supplies. The possibility of stealing from others depends on a forager's rank in the group. Highly ranked individuals can steal from subordinates and also protect their own caches. Since storing i...

Many food hoarding animals live in small groups structured by rank. The presence of conspecifics in the hoarding area increases the risk of losing stored supplies. The possibility of stealing from others depends on a forager’s rank in the group. Highly ranked individuals can steal from subordinates and also protect their own caches. Since storing i...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

This book introduces readers to a set of powerful and extremely flexible modelling techniques, starting at "square one" and continuing with carefully chosen applications. Some of these applications of methodology include insect oviposition behavior, overwinter survival of birds and fish, avian migration, resource management, conservation biology, a...

The idea of using marine reserves, where all fishing is banned is not new to fisheries management. It was first formally considered by Beverton and Holt but rejected in favour of approaches such as fleet and gear control. Since that analysis, many fisheries have collapsed worldwide, illustrating the vulnerability of fishery resources and the ineffe...

Overexploitation of marine fisheries remains a serious problem worldwide, even for many fisheries that have been intensively managed by coastal nations. Many factors have contributed to these system failures. Here we discuss the implications of persistent, irreducible scientific uncertainty pertaining to marine ecosystems. When combined with typica...

Using stochastic dynamic programming we modeled the hoarding and foraging behavior of tits and chickadees, Pandas, that are resident in the boreal forest at high latitudes. Here autumns have a rich supply of seeds and temperatures are relatively mild, while winters are cold with short days and a low food supply. We assumed that parids have a memory...

Guidelines for submitting commentsPolicy: Comments that contribute to the discussion of the article will be posted within approximately three business days. We do not accept anonymous comments. Please include your email address; the address will not be displayed in the posted comment. Cell Press Editors will screen the comments to ensure that they...

We present a dynamic model to examine sequential foraging decisions of predators searching for cryptic prey. We identify key elements of information processing and ecological factors determining the costs and benefits of two foraging alternatives. On the one had, specializing on a single prey type while ignoring other types increases the distance a...

Psychological studies have established that the central nervous system cannot sustain vigilance for an extended period of time. The consequent vigilance decrement implies a gradual reduction in the ability to process information effectively. This may result in a reduced ability to detect hidden predators, locate cryptic food items or make successfu...

Species in the avian family Alcidae show enormous inter- and intraspecific variation in age and mass at nest departure (hedging). We develop a dynamic programming model of the nest departure decision that incorporates the differential growth benefits and mortality costs of the pre- and postfledging habitats (nest and ocean). The model's most basic...

We model overwinter fattening strategies of dominants and subordinates as a stochastic dynamic game, basing our model on data pertaining to willow tits in Sweden. In the model the birds have two foraging habitats, one (outer branches) relatively rich in resources but also high in predation risk, the other (inner branches) less productive and less r...

Regular censuses conducted over a long time allow the calculation of both extinction and immigration rates. We present formulae for estimation of those rates. We use them on bird censuses of three British islands. These formulae improve on previous estimators of extinction but reaffirm that smaller populations have a higher probability of becoming...

Many species of animals face the continual problem of balancing the trade-off between reducing predation risks and maintaining or increasing their reproductive fitness. The terms of the trade-off are often asymmetric: each separate behavioral decision may lead to only a marginal increase in fitness, but may place the organism's entire future reprod...

We discuss a simple method, based on maximum likelihood, to estimate the rates of extinction and recolonization of a species, for example, on an island. Our method applies to both regular and sporadic surveys and thus allows one to use time series with missing data. When only a few surveys have been conducted, it may be possible to lump data from s...

Guidelines for submitting commentsPolicy: Comments that contribute to the discussion of the article will be posted within approximately three business days. We do not accept anonymous comments. Please include your email address; the address will not be displayed in the posted comment. Cell Press Editors will screen the comments to ensure that they...

The effects of variations in population size may be important in the evolution of individual behavior. We use simulation models to study the stochastic evolutionary contest between two behavioral strategies affecting individual survival and reproduction, one conservative (low fecundity and low mortality risk), the other risky (high fecundity and hi...

Life history theory and behavioral ecology, two branches in the study of adaptation, have relied extensively on mathematical models, but have tended to employ different types of models, and different currencies of fitness. Recently, a new approach based on dynamic, state variable models has been increasingly applied to the study of behavioral adapt...

What is maximized by natural selection? A general answer is the expected reproductive success of the individual; i.e. mean individual fitness. This basic fitness maximization principle underlies much of the modern evolutionary theory of adaptation (Fisher 1930, Williams 1966, Maynard Smith 1978). Criticism of the hypothesis of fitness maximization...

The interplay of demographic and environmental variance is considered in a behavioral context involving foraging in the presence of uncertain, fluctuating risk of predation. The evolutionary contest between two strategies — high risk and high fecundity versus low risk and low fecundity — is considered. Often the risky strategy will be dominant when...

We use dynamic-optimization models to assess the relative fitness consequences of inducible versus constitutive defense strategies. Our models assess the cost of defense in terms of reduced growth and reproduction of the defended organism. Resources are assumed to be allocated to growth, defense, or reproduction via a time- and state-dependent stra...

Many natural populations undergo radical and unpredictable fluctuations, associated with stochastic environmental conditions. Under such circumstances, fitness of a genotype (or ‘strategy’) is defined as the geometric mean of the intergenerational genotypic population growth ratel(t). Unfortunately, this population-level criterion has proved diffic...

Optimization models have often been useful in attempting to understand the adaptive significance of behavioral traits. Originally such models were applied to isolated aspects of behavior, such as foraging, mating, or parental behavior. In reality, organisms live in complex, ever-changing environments, and are simultaneously concerned with many beha...

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Previous work has demonstrated the value of dynamic programming models for the analysis of parental decision making. In the present paper we extend this approach to analyse conflicts between parents and their offspring, and develop a dynamic ESS model of feeding and fledging of nestling birds. In order to simplify the formulation and solution of th...

We use contemporary life history theory to analyze parental decisions concerned with the defense of offspring, and with the provisioning of offspring in the presence of risk. In achieving the optimal level of parental investment, the parent faces a tradeoff between present and future reproductive success. Our models, which are based on stochastic d...

The author presents an introduction to the theory of biologial conservation, including a wealth of applications to the fishery and forestry industries. The mathematical modelling of the productive aspects of renewable-resource management is explained, including both economic and biological factors, with much attention paid to the optimal use of res...

Within a brooding season, female fitness increases with time, clutch size, and body size. Fitness is very sensitive to the probability of attack by a potential predator. Nest defense generally maximizes female fitness only if the female is large enough to sustain the energetic demands of defense and has relatively few eggs remaining in her clutch,...

It is widely assumed that anaerobic diving is inefficient, and yet anaerobic dives are regularly observed in nature. We develop a model of diving, using a dynamic programming approach, that assumes dives are made to capture food. The essence of the model is that while aerobic diving is energetically efficient (in terms of glucose expended per mol o...

These notes developed from a series of lectures given originally at the University of Bremen in June 1986. They provide an introduction to the modeling of biological resource exploitation. Some of the material is covered in considerably greater detail in my books (Clark 1976a, 1985), but other topics represent more recent research. A numerically or...

The use of mathematical models in natural resource management has increased greatly over the past two or three decades, both in response to the perceived need for a more careful shepherding of the renewable resource base upon which life itself depends, and also as a result of improvements in analytical and computational techniques. In this review I...

The maximization of fitness is often used to analyse the action of natural selection on the life history of animals but short periods of behaviour receive ad hoc treatment. This article describes a dynamic, stochastic model for analysing behaviour in terms of the maximization of fitness.

Diel migrations between habitats containing different levels of food abundance is a common phenomenon among marine organisms, both vertebrate and invertebrate. We hypothesize that in many cases this behavior constitutes a response to diel changes in the relationship between potential feeding rates and predation risks in the different habitats. For...

In this book, Jon Conrad and Colin Clark develop the theory of resource economics. To begin, they provide an introduction to the required techniques of dynamic optimization. Throughout the book they build the reader's understanding with many fully-worked problems and numerical examples. The authors have written this text in the belief that the theo...

A Markovian decision model of the group foraging behaviour of lions, Panthera leo, in the Serengeti was formulated. The Markovian model predicts that, unless they have failed to eat for several days, lions maximize their fitness by a ‘satisficing’ type of behaviour, in which the size of foraging groups is such that each lion simply obtains its dail...

In this book, Jon Conrad and Colin Clark develop the theory of resource economics. To begin, they provide an introduction to the required techniques of dynamic optimization. Throughout the book they build the reader’s understanding with many fully-worked problems and numerical examples. The authors have written this text in the belief that the theo...

The problems facing a foraging animal have been studied on the basis of a variety of mathematical models. MacArthur and Pianka (1966) used marginality arguments familiar in economics to study optimal patch selection and optimal prey selection within patches. Fretwell (1972) discussed the equilibrium distribution of foragers among patches. Charnov (...

The application of stochastic dynamic programming, or Markov Decision Processes (MDP) to the modelling of behavior is discussed. Two examples are described: the hunting behavior of Serengeti lions, and the oviposition behavior of parasitic wasps. The MDP approach appears to explain the published data for these examples much more satisfactorily than...

A resource stock may be termed ‘renewable’ if constant periodic removals from it can be indefinitely prolonged. A renewable resource may be further classified as depletable or nondepletable, according to whether or not its productivity is affected by the level of exploitation. Biological resources such as fish, bird and animal populations, forests,...