A bioeconomic optimization approach for rebuilding marine communities: British Columbia case study

Abstract

SUMMARYMany marine ecosystems are depleted of living resources as a result of long-term overexploitation. Restoration plans should perhaps consider the entire ecosystem as opposed to single species, yet there is currently no suitable framework available for the design and comparison of whole-ecosystem restoration trajectories. This paper presents a novel addition to Ecopath with Ecosim's policy search routine, the ‘specific biomass’ objective function, which allows gaming scenarios to be run using selective fishing as a tool to rebuild depleted marine ecosystems or modify them into a preferred state. In this paper, restoration scenarios aimed to restore an ecosystem in Northern British Columbia to a state similar to the historic ecosystem of 1950 AD. Restoration plans that achieve restoration quickly tend to require a large sacrifice in fishery profits, while slower plans allow for continued harvest benefits. A convex relationship between profit and recovered biodiversity suggests that there may be an optimal rate of restoration. Cost-benefit analysis demonstrates that conservative restoration plans can offer a rate of return superior to bank interest when viewed as an investment in natural capital. Increasing the selectivity of fishing gear improves the economic outlook.