Olivier Thébaud

Modeling fleet response in regulated fisheries: An agent-based approach

Understanding the dynamics of fishing effort plays a key role in predicting the impacts of regulatory measures on fisheries. In recent years, there has been a growing interest in the use of bio-economic models to represent and analyze the short-term dynamics of fishing effort in response to regulation in the fisheries management literature. In this literature, fishing firms are usually modeled as autonomous decision-making units determining their harvest strategies so as to maximize profit, given technical and institutional constraints. The overall dynamics of a fishery is modeled as the result of these individual choices, and of interactions between individual choices due to the impacts of harvesting on the fish stock and/or problems of congestion. Applications have, for example, been related to the discussion of closed areas as fisheries management tools. A multi-agent model of a fishery targeting different species in different areas was developed to analyze the implications of taking into account the response of fishing fleets to such regulatory controls. The model is based on the Cormas platform developed for the simulation of the dynamics of common resource systems. An advantage of the multi-agent approach is that it allows a greater degree of complexity than standard bio-economic modeling tools, by focusing on local, rather than global, interactions. Simulation results are presented to illustrate how the model can be used to analyze the consequences of regulatory measures such as temporary fishing bans on the allocation of fishing effort between target species and areas, and the ensuing economic impacts of these measures.

Distributional issues in the operation of rights-based fisheries management systems

Rights-based management regimes are considered by economists as an important solution to the problems of excess capacity and biological over-harvesting of fisheries. In practice, adoption of such regimes, and particularly of those relying on individual quota allocations, has often met with resistance from within the fisheries concerned. A key reason for this resistance appears to be the distributional conflicts which arise in the process of implementing the regimes. An economic analysis of the nature of these conflicts in the different contexts in which they have been observed is proposed. The approach centres on the way in which distributional conflicts can influence the operation of management systems and their impacts on fisheries, from the country to the individual firm level. As an illustration, an analysis of the economic processes at firm level is developed based on the simulation of a fishery managed under individual transferable quotas.

Use of Incentive-Based Management Systems to Limit Bycatch and Discarding

In most fisheries, a number of species are unintentionally caught as bycatch while attempting to catch the targeted species. While much of the bycatch problem is technological in nature due to imperfect selectivity of the fishing gear, fisher behaviour also plays a major role. How, when and where fishers choose to fish can influence catch composition and thereby the quantity of bycatch. Behavioural changes can be encouraged through the development of an appropriate set of incentives — both economic and social — to avoid bycatch and reduce discarding. In this paper, a number of alternative incentive-based bycatch management systems are reviewed. The potential applicability of these systems to quota species, non-commercial species and threatened or conservation-dependent species (such as turtles, seals, dolphins) is reviewed, and examples of their application are presented. The review concludes that incentive-based approaches can reduce the level of bycatch and discarding in most fisheries.

Price integration in the Australian rock lobster industry: implications for management and climate change adaptation

Rock lobster fisheries are Australias most valuable wild fisheries in terms of both value of production and value of exports. Different states harvest and export different lobster species, with most of the landings being sent to the Hong Kong market. A perception in the Australian lobster industry is that the different species are independent on the export market, such that a change in landings of one species has no impact on the price of the others. This study investigates the market integration of Australian exports to Hong Kong for the four species and different exporting states. Our results indicate all four species and producers/export states are perceived to be substitutes for one another, so that, in the long run, prices paid to operators in the industry will move together. The integrated nature of the Hong Kong export market for Australian lobster suggests that the potential impacts of alternative fisheries management and development strategies at state and species levels cannot be considered in isolation, at least from an economic perspective. In addition, impacts of external shocks affecting production in one state (e.g. climate change) can be expected to affect all Australian lobster fisheries.

From anecdotes to scientific evidence? A review of recent literature on catch share systems in marine fisheries

In response to concerns regarding the global status of living marine resources, there has been a worldwide tightening of fishery access regulations. This has led to growing interest in individual transferable catch share programs, a market-based allocation approach to distribute fishing rights. However, the economic, ecological, and social benefits of these systems are the subject of continued debate. Here, we review empirical studies of transferable catch share systems published over the past decade. Our results show that, despite some of these systems having been in place for more than 20 years, systematic empirical assessments of their impacts are still rare. Furthermore, methods used to assess the impacts of catch share systems to facilitate comparisons remain under development, making it difficult to derive general conclusions from existing studies.

Facing the wave of change: stakeholder perspectives on climate adaptation for Australian seafood supply chains

Climate change is one of the most important issues confronting the sustainable supply of seafood, with projections suggesting major effects on wild and farmed fisheries worldwide. While climate change has been a consideration for Australian fisheries and aquaculture management, emphasis in both research and adaptation effort has been at the production end of supply chains—impacts further along the chain have been overlooked to date. A holistic biophysical and socio-economic system view of seafood industries, as represented by end-to-end supply chains, may lead to an additional set of options in the face of climate change, thus maximizing opportunities for improved fishery profitability, while also reducing the potential for maladaptation. In this paper, we explore Australian seafood industry stakeholder perspectives on potential options for adaptation along seafood supply chains based on future potential scenarios. Stakeholders, representing wild capture and aquaculture industries, provided a range of actions targeting different stages of the supply chain. Overall, proposed strategies were predominantly related to the production end of the supply chain, suggesting that greater attention in developing adaptation options is needed at post-production stages. However, there are chain-wide adaptation strategies that can present win–win scenarios, where commercial objectives beyond adaptation can also be addressed alongside direct or indirect impacts of climate. Likewise, certain adaptation strategies in place at one stage of the chain may have varying implications on other stages of the chain. These findings represent an important step in understanding the role of supply chains in effective adaptation of fisheries and aquaculture industries to climate change.

Ecological-economic modelling for the sustainable management of biodiversity

Terrestrial and marine biodiversity provides the basis for both ecosystems functioning and numerous commodities or services that underpin human well-being. From several decades, alarming trends have been reported worldwide for both biodiversity and ecosystem services. Therefore the sustainable management of biodiversity requires a double viewpoint balancing ecological conservation with the welfare of human societies. Understanding the underlying trade-offs, synergies and interactions imposes the development of interdisciplinary researches and methods. In that respect, bio-economic or ecological economic modeling is likely to play a major role. The present paper intends to elicit the key features, strengths and challenges of bio-economic approaches especially in mathematical and computational terms. It first recall the main bio-economic methods, models and decisional instruments used in these types of analyses. Then the paper shows to what extent bio-economic sustainability lies between equilibrium, viability and optimality mathematical frameworks. It ends up by identifying new major challenges among which the operationalization of ecosystem based management, the precautionary principle and the implementation of governance are especially important.

EXTERNALITIES, INSTITUTIONS AND THE LOCATION CHOICES OF SHELLFISH PRODUCERS: THE CASE OF BLUE MUSSEL FARMING IN THE MONT-SAINT-MICHEL BAY (FRANCE)

ABSTRACT Most marine aquaculture activities remain strongly dependent on coastal ecosystems. In the case of shellfish farming, this dependency is related mainly to water quality and to the various ecological interactions resulting from the dynamics of coastal food webs. Such ecological constraints have influenced the overall evolution of blue mussel farming in the Mont-Saint-Michel Bay, leading producers to negotiate collective arrangements regarding production capacity and techniques and to develop production strategies at the farm level. This article presents an analysis of the location choices of mussel farmers in the Mont-Saint-Michel Bay based on an empirical investigation conducted in 2002. A typology of farms with respect to their land structure is developed in which some farms choose to concentrate their activity in a single part of the bay while others distribute their activity more widely. Determinants of the location choices of each farm category, including distance to port, natural productivity differentials, and predation of mussel stocks, are analyzed. The role of the institutional arrangements allowing mussel farmers to develop these location strategies is also discussed.

Keeping Humans in the Ecosystem

The World Ocean presents many opportunities, with the blue economy projected to at least double in the next two decades. However, capitalizing on these opportunities presents significant challenges and a multi-sectoral, integrated approach to managing marine socio-ecological systems will be required to achieve the full benefits projected for the blue economy. Integrated ecosystem assessments have been identified as the best means of delivering the information upon which marine resource management decisions can be made. By their nature, these assessments are inter-disciplinary, but to date have mostly focused on the natural sciences. Inclusion of human dimensions into integrated ecosystem assessments has been lagging, but is fundamental. Here we report on a Symposium, and the articles emmanating from it that are included in this Theme Set, that address how to more effectively include human dimensions into integrated ecosystem assessments. We provide an introduction to each of the main symposium topics (governance, scenarios, indicators, participatory processes, and case studies), highlight the works that emerged from the symposium, and identify key areas in which more work is required. There is still a long way to go before we see end-to-end integrated ecosystem assessments inclusive of all the major current and potential ocean use sectors that also encompass multiple aspects of human dimensions. Nonetheless, it is also clear that progress is being made and we are developing tools and approaches, including the human dimension, that can inform management and position us to take advantage of the multi-sectoral opportunities of sustainable blue growth.

Estimating Proxy Economic Target Reference Points in Data-Poor Single-Species Fisheries

Abstract Bioeconomic models have been developed and applied to a range of fisheries around the world. However, an even greater number of fisheries are relatively data poor, and development of traditional bioeconomic models is not feasible. For small-scale fisheries, the cost of data collection and model development may exceed the additional value these models may generate. Fisheries biologists have grappled with similar issues and have developed a range of data-poor methods for estimating reference points related to fishing mortality based on life history characteristics and other indicators. In other cases, catch and effort data may be sufficient to estimate sustainable biomass levels. However, model-derived economic target reference points require robust biological models as well as appropriate economic information, both of which are often unavailable. In this paper, we extend the data-poor work to move from biological to economic target reference points for single-species fisheries. We show that the relationship between economic (maximum economic yield) and biological (maximum sustainable yield) reference points depends primarily on the cost : revenue ratio, and that, where unavailable, these can be inferred from fisheries characteristics. We show that good estimates of biomass- and effort-based economic target reference points can be achieved with limited data.