The Green Band: Using Production and Catch to Judge Distortive Pressure on an Ecosystem

Abstract

Ecosystem based fisheries management is an increasingly accepted approach for many fisheries management agencies. Indicators and methods that can usefully support the aspiration of making ecosystem based fisheries management decisions on tactical time frames are slowly accumulating, but have primarily focused on biomass status and trends. We first verify that fishing can distort the cumulative distribution of connections within an ecosystem, and then show (via theoretical testing and application to four contrasting case study locations) how relating catch with production by defining an acceptable band of exploitation pressure - the "Green Band" - can help inform fisheries decision makers as to whether an ecosystem is under distortive patterns of fishing pressure that will ultimately undermine the structure of the ecosystem.