The economic value of fisheries harvest supported by saltmarsh and mangrove productivity in two Australian estuaries

Abstract

Broad-scale links between productivity of estuarine habitats (such as saltmarsh and mangrove) and the exploited species that rely on them have often been used to build a case for habitat conservation and repair. Stable isotope composition can provide a temporally and spatially integrated measure of trophic connectivity with which to quantify habitat-fishery linkages, allowing primary producers that comprise these habitats to be linked with harvested biomass with relatively few assumptions. We present a novel model that applies this approach to estimate the economic value of fisheries harvest derived from dominant estuarine habitats, in two eastern Australian estuaries. Estimated values of fisheries harvest supported by habitats within the model regions ranged from ∼AUD100,000y−1 to ∼AUD7,200,000y−1. Saltmarsh in the Clarence River had by far the greatest economic value per-unit-area, with an average estimated Total Economic Output (from fisheries harvest) of AUD25,741ha−1y−1, whereas mangrove was estimated to be AUD5,297ha−1y−1. Average Total Economic Output in the Hunter River was AUD2,579ha−1y−1 and AUD316ha−1y−1 for saltmarsh and mangrove habitats respectively. Estuarine habitats are key ecological indicators of fisheries productivity, and the framework presented here will be broadly useful in estimating the potential economic impacts associated with changes in these indicators.