A Coral-Safe Diving Reminder Reduces Reef Contacts by Ashton
PROTECTING GUAM’S CORAL REEFS BY IMPROVING SCUBA DIVER BEHAVIOR: A CORAL-SAFE DIVING REMINDER REDUCES REEF CONTACTS BY ASHTON N. WILLIAMS A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE IN BIOLOGY SUPERVISORY COMMITTEE Dr. Laurie Raymundo, Chair Dr. Alexander Kerr, Member Dr. Romina King, Member UNIVERSITY OF GUAM DECEMBER 2019 Abstract Coral reefs are a critical resource for the culture and economy of the American territory of Guam, but the island’s coral reef resources are increasingly imperiled by climate change, particularly bleaching caused by rising seawater temperatures. Severe bleaching events in 2013, 2014, 2016, and 2017 have caused mass mortality of corals and made evident the critical need to reduce local stressors to protect the future of Guam’s reefs. An estimated 300,000 people scuba dive on Guam’s reefs annually, but the impacts of these divers are unknown. This study examines the impacts of scuba diving activity on highly trafficked coral reefs and tests a low-effort approach to reducing diver impacts by using a coral-safe diving reminder. Comparisons of benthic cover, genus diversity, and health impacts did not reveal any significant differences between pairs of often dived and rarely dived sites, although it is likely that the damage and mortality caused by recent bleaching events may be masking the smaller impacts of scuba divers. A single-sentence coral-safe diving reminder delivered as part of the standard pre-dive briefing was highly effective in reducing both accidental and intentional contacts with reef. Divers who received a coral-safe diving reminder made 72% fewer contacts with the reef, and about 60% fewer contacts with live corals specifically, than divers who did not receive a reminder.
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