Protecting endemic species from African Catfish invasion when community behavioral responses get in the way

Abstract

Exotic invasive fish species, when introduced into pristine natural environments, threaten the survival of many endemic species. Management challenges associated with controlling their further spread and protecting endemic species can be exacerbated when the same exotic fish species also provide gastronomical benefits to humans. Local human populations can switch their consumption preferences toward the exotic fish species, leading to an increase in their spread rate and control costs. Using the example of the African Catfish invasion in a freshwater lake, we develop a bioeconomic model of its optimal control, which also incorporates the behavioral challenges arising from a gastronomical preference for the exotic fish species. In particular, the cost of catfish control increases with its consumption demand, which, through altering the inter-species dynamics, threatens the survival of endemic fish species. The manager has at his disposal the market and non-market values of the endemic fish species to invest toward their preservation efforts. The non-market value of the endemic species is further modeled as endogenous to the community’s preference switching. Results suggest that a late detection of the exotic fish species in freshwater bodies can increase their control costs enough to make their eradication challenging, especially when the manager faces financial resource constraints. The presence of behavioral effects adds to this challenge — directly, through increasing the control costs, and indirectly, through lowering the non-market value of the endemic fish species.