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

Ram Ranjan,Vassilis G Aschonitis

doi:10.1371/journal.pone.0209009

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.

Highlights

Exotic species invasion, in combination with habitat degradation, poses significant threats to global biodiversity through causing large-scale extinction of endemic species [1]
Using the example of the African Catfish invasion in a freshwater lake, we develop a bioeconomic model of its optimal control, which incorporates the behavioral challenges arising from a gastronomical preference for the exotic fish species
Protecting endemic species from African Catfish invasion value of 2 would make the cost of control highly non-linear, thereby creating significant tradeoffs between current eradication efforts spent on invasive species control and future values derived from the endemic fish species

Summary

Introduction

In combination with habitat degradation, poses significant threats to global biodiversity through causing large-scale extinction of endemic species [1]. The African Catfish (Clarias Geriepinus), which threatens the survival of multiple endemic species globally, has been difficult to eradicate due to its increasing preference and commercial breeding for consumption purposes [2]. The economic rewards from commercial breeding of catfish are far higher compared to endemic species, given the former’s ability to grow rapidly (yielding more weight per fish) irrespective of the quality of the habitat or feed [3]. When such invasive species provide economic and culinary benefits to local communities, the cost of their control and eradication increases due to a lack of cooperation and resistance from the local communities. Using gastronomy to control the invasive species population may not be an effective tool, as it could lead to their further commercial breeding and spread into new areas [4,5]

Methods

Results

Discussion

Conclusion