This paper deals with the economic impact of the
invasion of a scallop fishery by an exotic shellfish that was accidentally
imported some decades ago. The invasive alien species, a slipper-limpet,
Crepidula fornicata, is a space competitor for local scallops, and its spread threatens the
sustainability of the ongoing scallop restocking program. Facing this
invasion, the local fisheries committee has initiated a containment project
intending to make the restocking program consistent with the exotic species
presence in the fishery. The issue is complicated by the occurrence of
occasional toxic micro-algae blooms affecting the scallop fishery. The paper
presents a model dealing with the economic impact of the invasive process,
and a methodology for cost-benefit analysis of invasion management.
According to numerical simulation, the invasion is a serious threat to the
economic viability of the restocking program, and invasion management would
help maintaining the long term sustainability of the fishery. Sensitivity
tests highlight the importance of long term equilibrium scallop catches on
the program result, depending on scallop farming technical performance and
ecosystem disturbance.