Reconciling economic and biological modeling of migratory fish stocks: Optimal management of the Atlantic salmon fishery in the Baltic Sea

The paper puts forward a model of the Atlantic salmon fishery in the Baltic Sea that integrates the salient biological and economic characteristics of migratory fish stocks. Designed to be compatible with the framework used for actual stock assessments, the model accounts for age-structured population dynamics, the seasonal harvest and competing harvesting by commercial and recreational fishermen. It is parameterized for the Simojoki River stock. The socially optimal policy for maximizing discounted net benefits from the fishery within an uncertain environment is determined using a dynamic programming approach and numerical solution method. Our results indicate that substantial economic benefits could be realized under optimal management without compromising stock sustainability.     

Preference for Landings’ Smoothing and Risk of Collapse in Optimal Fishery Policies: The Ibero-Atlantic Sardine Fishery

Several world fish stocks are being explored at unsustainable levels and require management plans to rebuild stock abundance. Defining a management plan is, however, a complex task that entails multidisciplinary work. In fact, while it requires solid scientific knowledge of fish stocks, the inclusion of economic and social objectives is crucial to a successful management implementation. In this paper we develop an age-structured bioeconomic model where the objective function is modified to accommodate preferences from different stakeholders. In particular, we consider important characteristics that a management plan should take into account: profit maximization, fishermen’s preference for reducing landings’ fluctuations and risk of fishery collapse. Modeling preferences for reducing landings’ fluctuations is accomplished by defining a utility function with aversion to intertemporal income fluctuations. Building upon biology literature, we model precautionary concerns by incorporating a probability of collapse that depends on current spawning biomass. We illustrate how this framework is able to assist in the analysis and design of harvest control rules applying it to the Ibero-Atlantic sardine stock.     

Fisheries Management in Congested Waters: A Game-Theoretic Assessment of the East China Sea

Environmental and Resource Economics - Fisheries in the East China Sea (ECS) face multiple concerning trends. Aside from depleted stocks caused by overfishing, illegal encroachments by fishermen...     

Aquaculture,capture fisheries,and wild fish stocks

This paper employs a general equilibrium model to examine how the rise of aquaculture and changes in wild fish stocks are related for herbivorous fish species. Two influences, human population growth and technological improvement in aquaculture, are studied. Both of these factors raise aquaculture production, but human population growth reduces wild fish stocks, while technological progress in aquaculture raises wild stocks.     

Ecological and economic sustainability in fishery management: A multi-agent model for understanding competition and cooperation

Recent studies have shown that many marine ecosystems are experiencing an accelerating loss of population and biodiversity. It is apparent that there is a growing disparity between the available supply of fish and the desire of the growing world population to catch them. Although studies have begun to question the ecological sustainability of managed fishery systems, they often omit the corresponding effects on the economic sustainability of fishery industries. This is particularly important in rural coastal areas where the fishing industry is often a dominant employer. In this article, we analyze the interactions between economic and ecological dynamic systems using a multi-agent dynamic model of fishery management. Multiple agents (fishers) harvest multiple fish species and adapt the amount and allocation of their effort to their value functions, which are given as net profits of the fish harvest sold for a market price. This is largely unique in fishery models, since many econometric studies view fishers as represented by homogenous ‘average’ agents. We introduce and compare two different decision rules governing the behavior of fishers engaged in a competitive market. We demonstrate a situation where both behaviors lead to a decline of all fish stocks, as well as profits for most fishers. As an alternative, we introduce a cooperative approach in which fisheries jointly set sustainable limits for total harvest and effort that are then distributed to the fishers according to distribution rules. The simulation reveals that fish stocks and profits can stabilize at significantly higher levels in the cooperative case, leading to a continuous accumulation of capital for all fishers. This model demonstrates key aspects of overfishing conflicts that can be overcome through planned fishing quotas and cooperative market mechanisms. It also demonstrates a novel approach for simulating the dynamic behavior of heterogeneous fishers.     

A model for estimating fish population and optimal fishing effort in lakes and rivers

We developed a model for estimating the fish population for various species in lakes and rivers. Our estimation focuses, in its first step, on fish species that breed outside the lake. Using the annual outside supply of fingerlings, natural survival rate and reported amounts of fish caught, we estimated fish stock. Given the estimated stock for fish bred outside the lake, we can evaluate the catch rate. Assuming equal catch rates for other species, and given the amount caught for each species, we are able to evaluate each species stock. Using the proposed technique, we evaluated various species stocks in the Sea of Galilee (Lake Kinneret) in Israel. Using our suggested technique for evaluating fish stock, we calculated the optimal effort of fishing needed for maximizing steady state profit of the fishers.     

Volatility and stock price indexes

The stochastic approach to index numbers has been successfully applied to the estimation of inflation, the world interest rate and international competitiveness.?One distinct advantage of this approach is that it provides the whole distribution of the index, not simply one value. In this article, we extend the stochastic approach to the estimation of a stock market index. We demonstrate how this approach can be used to identify ‘redundant stocks’ that do not contribute significantly to the overall index.?For index tracking purposes, these stocks can be safely excluded.     

ITQ’s in Chile: Measuring the Economic Benefits of Reform

In 2001 an individual (operationally transferable) quota system was introduced for all the most important industrial fisheries in Chile. This system was put in place after years of declining stocks and over investment. In this paper we describe this reform and estimate related allocative efficiency benefits for the most important industrial fishery in the country, the southern pelagic fishery. Benefits were estimated using a bioeconomic model estimated using data for the 1985–2004 period. The estimated model was then used to generate simulated scenarios of the evolution of this fishery in a 20 year horizon with and without the ITQ system in place. The benefits of the reform can then be estimated by comparing the fishery’s costs in the scenarios with and without ITQs. This approach allows benefits to be estimated using more realistic counterfactual scenarios than just comparing the fishery before and after the reform. Estimated discounted net benefits reach US $166 million in the period 2001–2020. Fleet size fell from 149 active boats in 2000 to 57 in 2004 as a direct consequence of the reform. Among the interesting features of the Chilean experience is the way the political economy of the reform was facilitated by the prior introduction of de facto individual quotas within the framework of fishery experimental activities. When the authorities closed the southern pelagic fishery because of biological problems between 1997 and 2000, they organized ‘experimental’ fishing expeditions in which participant boats were given the right to fish a certain amount of resources per expedition. This pseudo quota system allowed fishermen to experience directly the benefits of individual quotas and that was instrumental to the political agreement leading to the reform. It is important to note that the Chilean southern industrial pelagic fishery has average catches of over 1.4 million tons a year, making it one of the largest fisheries in the world to be regulated by individual quotas.     

Methods for Environmental and Economic Accounting for the Exploitation of Wild Fish Stocks and their Applications to the Case of Icelandic Fisheries

The paper discusses methods for estimating the value of commercially exploited fish stocks and the cost of exploiting them. Methods which are recommended in the System of National Accounting (SNA) satellite system and the System for Integrated Environmental and Economic Accounting (SEEA) and relevant for this task are discussed. The paper questions the relevance of some of these methods. It argues for the integration of economic accounting for wild fish stocks with estimation of efficient management of them. Using biological and economic data makes it possible to produce consistent estimates of the value of fish stocks and the cost of exploiting them. These estimates are useful for national accounting and for guiding management of fisheries. This method allows estimation of the cost of inefficiency of fisheries management besides estimation of the cost of depletion. The different methods are illustrated using data on commercial fisheries in Iceland and the fish stocks that they exploit. It is shown that even if all methods are based on market valuation and use only objective data they lead to very different outcomes.     

Factors influencing the adoption of ICT tools in Kerala marine fisheries sector: an analytic hierarchy process approach

Adoption of a new ICT tool in the fisheries sector depends on several factors such as ease of use, affordable cost, information, and time. All these factors determine the preference of an existing tool over others for productivity enhancement. Which ICT tool is more beneficial than others is a continuing debate among researchers. However, the literature currently lacks detailed studies of fishermen criteria for selecting the best ICT tools in the marine fisheries sector. This paper is based on a framework which explains the factors influencing the adoption of ICT tools for the better fish catch, with the help of a multi-criteria decision making approach, called Analytic Hierarchy Process. Also, in the study we have compared the results of analysis using AHP with popular method TOPSIS and the obtained results were validated. The Study also assesses scientifically, which is the most important ICT tool for fishing through a case study in Northern and Southern parts of Kerala, a state in the southern India. The Study finds that Global Positioning System (GPS) is the most beneficial and important ICT tool in marine fishing. In contrast to the earlier studies, the results show that wireless set is important than other tools like mobile phone and echo-sounder for multi-day fishing. The cost-benefit analysis also supports findings of the study.     

An Enforcement-Coalition Model: Fishermen and Authorities Forming Coalitions

The paper sets up a four-stage enforcement model of fish quotas. The purpose of the paper is to show how the level of enforcement set by the authorities affects the way fishermen form coalitions. We show that a high level of control effort yields less co-operation among fishermen, while in the case of low control effort, coalitions are somewhat self-enforcing. The paper further discusses how the optimal enforcement level changes when the coalition formation among authorities changes: centralised, partly centralised and decentralised authorities. We show that decentralised authorities set a lower level of control effort compared to the centralised authorities. The theoretical results are illustrated by simulations of the Baltic Sea cod fishery.The authors acknowledge valuable comments and suggestions from Frank Jensen and Niels Vestergaard.     

Open access,common property and scarcity rent in fisheries

Open access resources are frequently not managed efficiently, resulting in falling stock levels and a declining income for fishermen. In the late 1970's, the policy response to this problem was the implementation of 200-mile fishing zones, which enabled the European Union to formulate and implement the Common Fisheries Policy, aimed at (among other things) conservation and distribution of available stocks. In Germany, this shift from an open access regime towards a common property regime had favourable outcomes. The trend of falling prices was reversed. The conclusion was that intertemporal efficiency had increased as a result of (inter)governmental policy. Apparently, a wedge was formed between price and marginal harvesting costs, implying that scarcity rent had returned as a component of prices.     

Bioeconomic Analysis of By-Catch of Juvenile Fish in the Shrimp Fisheries – an Evaluation of Management Procedures in the Barents Sea

A bioeconomic model on the management ofby-catch of juvenile fish in the shrimp fisheryin the Barents Sea and the Svalbard Zone,presented by the Norwegian Directorate ofFisheries to the Joint Norwegian RussianFisheries Commission in 1993, is evaluated. The model is based on management of by-catchthrough closure of areas when the by-catch ofjuvenile fish from commercially importantspecies exceeds a critical number. It isargued that although the model may prove usefulin bringing economic rationale into themanagement of by-catch, care must be taken whenstocks are in poor shape. This is illustratedby using the high mortality rates and low stocklevels experienced for cod and haddock in 2000,and which is expected for the next couple ofyears. It is therefore discussed when it isappropriate to use the model with reference tothe Code of Conduct provided by FAO in 1995.     

PRIVATE PROPERTY RIGHTS AND CRISES IN WORLD FISHERIES: TURNING THE TIDE?

This paper addresses the crises in the world's fisheries involving dwindling stocks, overcapitalization, and jurisdiction disputes from a property rights perspective. In particular, it examines the causes of the problems fishers face and explores the potential of privatizing the right to catch fish as a means to address the crises. The analysis assesses experiences of private harvesting rights with reference to monitoring and enforcement, allocating rights, economic benefits, adjustments in the fishery, and resource rents. It also examines issues such as fluctuating fish stocks, straddling stocks and high seas fisheries, and the endemic poverty of many artisanal fisheries in the context of current fisheries practice.     

The economic costs to fisheries because of marine sand mining in Ongjin Korea: Concepts, methods, and illustrative results

We illustrate a methodology for estimating the damages to commercial fisheries from entrainment and from temporary loss of seafloor habitat productivity because of marine sand mining. A Beverton-Holt, year-class model is used to estimate illustrative short-term, long-term, and indirect (food web) effects from the inception of mining through the time to recovery of the injured resource stocks. A Base Case analysis evaluates hypothetical mining for a 4 km² mining site with biological recovery of the mined area beginning seven months after mining ceases and the bottom excavation fills in. Sensitivity analyses also are used to illustrate damages for alternative recovery paths and for 20 hypothetical mining sites for one year of mining and for recurring mining for 5 and for 10 years. Important qualifications and directions for further research are outlined.     

Property rights regimes in complex fishery management systems: A choice experiment application

The Tonle Sap wetland fishery was previously divided into 3 different management zones for conservation, open access fishing and private fishing. Rights to the private fishing zone involved auctions for exclusive rights to temporarily designated plots. This paper aims to explore the auction-based system by investigating how this fishery management system affects different groups of small scale fishermen and how different characteristics of the fishing lots affect the bidding. A choice experiment approach was used to model fishermen's choices in a hypothetical auction market by offering fishermen the choice between purchasing different potential fishing lots and a no purchase option, implying fishing only in the communal fishing grounds. The preferred latent class model with two segments of fishermen showed that the bidding behavior of the more privileged group out-competes the other group irrespective of the lot characteristics. This result suggests that it is unlikely that the redesign of the auction system itself would be an effective way of securing access to fishing resources for the two observed groups of fishermen. This implies that open access fishing grounds and/or other regulations may also be needed in future management as they serve an important role for the poorer segments.     

上市公司股权结构、激励制度及绩效的实证研究

股权结构的分散性与国家股的大小呈负相关,与流通股的大小呈正相关。公司经营绩效与股权结构分散性、经理人员拥有的公司股权大小、职工持股呈正相关,与国家股的大小、经理人员薪金等呈负相关。     

Optimum reserve size,fishing induced change in carrying capacity,and phenotypic diversity

Fish stocks around the world are heavily overexploited in spite of fishing policies in several parts of the world designed to limit overfishing. Recent studies have found that the complexity of ecological systems and the diversity of species, as well as negative impact of fishing activities on environmental carrying capacity of fish stocks—all contribute to the problem. A number of biologists, managers, and practitioners strongly support the use of marine reserves as a management strategy for marine conservation. This paper contributes to this line of research by seeking an optimum reserve size and fishing effort for situations where species diversity decrease at fishing grounds and fishing activities impact carrying capacity. We found that a reserve size which maximizes economic rents could ruin a fish stock if fishing impacts are not accounted for. On the other hand, the reserve serves as a bifurcation term which could improve the resilience of a marine ecosystem.     

Bioeconomic Analysis and Management

This article discusses bioeconomic analysis and different management strategies in fisheries. It reviews recent developments, which show the need to expand the analysis to multispecies fisheries and management. Significant gains can be made if the interdependencies between species and/or jointness in inputs for many fisheries are identified. Both common property resource management and individual transferable quotas (ITQs) can be fruitful strategies in different settings. The article suggests that there is scope for the development of a multiple use management approach of marine resources. Besides the aim of an efficient use of fish stocks, equal attention should be given to other values from aquatic ecosystems, like ecological services, biodiversity and recreation possibilities.     

Boundary conditions for the sustainable use of major fish stocks in the Baltic Sea

The history of the management of Baltic fishery resources suggests that both biological and non-biological factors influence management decisions and that both types of information are essential for management which promotes sustainability. There is a direct link between the exploitation level and the risks for fishing as an economic activity due to fluctuations in the resource. This paper analyses the sustainability of the present catch levels of major Baltic fish stocks. By examining the rate of fishing mortality and recruitment variability, the possibility of sustaining present catch levels can be investigated. Current catch levels of Baltic cod and some salmon stocks are not sustainable whereas sprat and herring catches are. High rates of fishing mortality of cod and salmon may endanger stocks if a drop in the recruitment causes an increase of the fishing mortality rates in order to sustain short-term catches. By analysing the trade off between exploitation level and risk of stock decline, managers can obtain a basis for quota negotiations.