Bioeconomic model of the dynamics of fisheries facing global economic and environment changes: the French Guyana shrimp fishery
In the past two decades, the French Guyana shrimp fishery has known dramatic evolutions, largely driven by global changes. On the economic side, two major driving factors are the globalization of the shrimp market, with a decreasing trend in real prices, an d the long-term increase in fuel prices worldwide. On the environmental side, recruitment of the two main species of shrimp targeted in the fishery seems to have decreased over the last decade. This decrease is probably related to hydroclimatic modifications linked to global change. It is important to assess the adaptive capacity of the fishery facing such changes, as well as the
relevance of past and future public policies to improve this capacity.
A key component of this adaptive capacity is the way in which fishing firms assess tradeoffs and make decisions regarding alternative fishing strategies. In the French Guyana shrimp fishery, of particular interest is the comparison which firms make between maximizing catch volume and maximizing catch value. Because of the strong relationship between size and price per kg for shrimps, a maximum value strategy leads to significantly different exploitation choices than the maximum catch strategy, in terms of effort allocation in space and time, and of gear selectivity. The existence of a volume-based subsidy in the fishery however influences this trade-off, as it creates an incentive to maximize catch volume rather than catch value.
A bioeconomic model of the French Guyana shrimp fishery was developed in order to analyze the dynamics of the fishery. The aims of the modeling exercise were: 1) to account for the changes observed in the fishery over the past ten years and major drivers of those changes; 2) to simulate possible responses of the fishery to economic changes but also to environmental perturbations or regime shifts; and 3) to assess the consequences of past and possible future public policies on the bioeconomic viability of the fishery.
The aim of this paper is to present the key results derived from this modeling exercise, as regards assessment of the adaptive capacity of the fishery to global changes, and the role of public policies in this respect. The paper is structured as follows. Section 1 provides a brief introduction to the shrimp fishery and its evolution over the past decade. Section 2 presents the general characteristics of the simulation model. Section 3 presents the adjustment of the model to historical data and the probable future trends in the fishery given the current status of major driving fact ors, showing that strong adaptations are necessary in the fishery if the recent trends in economic parameters still hold in the future. Section 4 assesses the role of harvesting strategies in explaining the changes observed and the influence of public policies on these strategies. Section 5 discusses these results, in the light of alternative public policies which could facilitate adaptation of the
fishery to its changing environment, and concludes.
This research was carried out as part of the “Chaloupe” program (http://www.projet-chaloupe.fr) funded by the French National Agency For Research (ANR). The objective of the program is to study the adaptation capacity of exploited marine communities and fisheries, facing environmental and economic global changes, based on the comparative analysis of different case studies.
Keyword(s)
bioeconomic modeling, fishery management, subsidies, shrimp, French Guyana
Chaboud Christian, Thebaud Olivier (2009). Bioeconomic model of the dynamics of fisheries facing global economic and environment changes: the French Guyana shrimp fishery. Anderssen, R.S., R.D. Braddock and L.T.H. Newham (eds) 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation. Modelling and Simulation Society of Australia and New Zealand and International Association for Mathematics and Computers in Simulation, July 2009, pp. 2078-2086. ISBN: 978-0-9758400-7-8. https://archimer.ifremer.fr/doc/00243/35473/