Benthic community structure on coral reefs exposed to intensive recreational snorkeling

Abstract

Chronic anthropogenic disturbances on coral reefs in the form of overfishing and pollution can shift benthic community composition away from stony corals and toward macroalgae. The use of reefs for recreational snorkeling and diving potentially can lead to similar ecological impacts if not well-managed, but impacts of snorkeling on benthic organisms are not well understood. We quantified variation in benthic community structure along a gradient of snorkeling frequency in an intensively-visited portion of the Mesoamerican Barrier Reef. We determined rates of snorkeling in 6 water sections and rates of beach visitation in 4 adjacent land sections at Akumal Bay, Mexico. For each in-water section at 1–3 m depth, we also assessed the percent cover of benthic organisms including taxa of stony corals and macroalgae. Rates of recreational snorkeling varied from low in the southwestern to very high (>1000 snorkelers d-1) in the northeastern sections of the bay. Stony coral cover decreased and macroalgal cover increased significantly with levels of snorkeling, while trends varied among taxa for other organisms such as gorgonians, fire corals, and sea urchins. We conclude that benthic organisms appear to exhibit taxon-specific variation with levels of recreational snorkeling. To prevent further degradation, we recommend limitation of snorkeler visitation rates, coupled with visitor education and in-water guides to reduce reef-damaging behaviors by snorkelers in high-use areas. These types of management activities, integrated with reef monitoring and subsequent readjustment of management, have the potential to reverse the damage potentially inflicted on coral reefs by the expansion of reef-based recreational snorkeling.

Fluctuations in coral reef fish densities after environmental disturbances on the northern Great Barrier Reef

“…We acknowledge an important caveat in the present study: we were unable to incorporate information about the benthic habitat structure and benthic communities. This information would provide more insight into the fluctuations in reef-dependent fish communities (Goren & Spanier, 1985; Holbrook, Schmitt & Stephens, 1997; Russ & McCook, 1999; Wismer, Hoey & Bellwood, 2009; Pizarro et al, 2017; Prazeres, Roberts & Pandolfi, 2017; Renfro & Chadwick, 2017). Also, due to the absence of data on the benthos, the significant effect of “site” in our model is virtually impossible to interpret (see Figs.…”

Investigating Reef Contact Rates of Snorkel Visitors at Koh Sak, Pattaya on Guided and Non-guided Coral Reef Tours

“…Studies investigating snorkeler's contact rates with the coral reef substratum are scarce in the literature; most studies instead focus on the overall impact of snorkelling. High-use reef sites experience more damage than low-use sites [19][20][21] showing that Koh Sak is no different to other reef sites around the world [12]. Contact rates in this study are lower than rates measured for snorkelers in Puerto Rico [22]; in that study, snorkelers contacted the reef at a rate of 0.26 min -1 but 39 % of contacts were made by snorkelers wearing fins suggesting that it was accidental contact.…”

Fisheries and Tourism: Social, Economic, and Ecological Trade-offs in Coral Reef Systems

“…However, tourism-related threats such as enhanced sedimentation from changes in land use, loss of habitat due to land reclamation, expulsion of sewage and solid waste, and overuse by snorkelers and divers ( Fig. 13.4) can contribute to reduced ecosystem resilience or phase shifts away from coral-dominated ecosystem states (Hawkins and Roberts 1994;Redding et al 2013;Lamb et al 2014;Renfro and Chadwick 2017), thereby jeopardizing tourismbased livelihoods (Smith et al 1981).…”

“…Managers and conservationists should consider the ecological trade-offs between tourism and fisheries industries. Overuse through heavy fishing, land-use change, or poor waste management can all lead to coral reef degradation, phase shifts, and even reef fishery collapse (Hawkins and Roberts 1994;Cesar et al 2003;Mumby et al 2006;Fenner 2012;Redding et al 2013;Lamb et al 2014;Bozec et al 2016;Renfro and Chadwick 2017). While balancing the ecological trade-offs between coral reef fisheries and tourism, management strategies must also align with the social and economic interests of workers.…”