Setting sustainable limits on anchoring to improve the resilience of coral reefs

• Published in: Marine pollution bulletin 2023-04, Vol.189, p.114721-114721, Article 114721
• Main Authors: Mason, Robert A.B., Bozec, Yves-Marie, Mumby, Peter J.
• Format: Article
• Language: English
• Subjects: Anchoring; Animals; Anthozoa; Benthic impacts; Carrying capacity; Climate; Climate Change; Conservation of Natural Resources; Coral reef; Coral Reefs; Ecological modelling; Ecosystem
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2023.114721

Boat anchoring is common at coral reefs that have high economic or social value, but anchoring has received relatively little attention in reef resilience studies. We developed an individual-based model of coral populations and simulated the effects of anchor damage over time. The model allowed us to estimate the carrying capacity of anchoring for four different coral assemblages and different starting levels of coral cover. The carrying capacity of small to medium-sized recreational vessels across these four assemblages was between 0 and 3.1 anchor strikes ha−1 day−1. In a case study of two Great Barrier Reef archipelagos, we modelled the benefits of anchoring mitigation under bleaching regimes expected for four climate scenarios. The partial mitigation of even a very mild anchoring incidence (1.17 strikes ha−1 day−1) resulted in median coral gains of 2.6–7.7 % absolute cover under RCP2.6, though benefits varied temporally and depended on the Atmosphere-Ocean General Circulation Model used. •Anchoring impacts on a coral reef were simulated with an individual-based model.•The model allowed the carrying capacity of anchoring at coral reefs to be estimated.•Carrying capacity ranged between 0 and 3.1 strikes ha−1 day−1.•Anchoring impacts were modelled under heat stress regimes of four climate scenarios.•Mitigation of even very mild anchoring impacts increased reef resilience under RCP2.6.