Science and Mathematics Faculty Presentations

Title

Does Recreational Diving Impact Hawksbill Sea Turtle Sighting Rates? Preliminary Analysis for a Marine Protected Area, Honduras

Document Type

Poster Session

Conference/Event

35th Annual Symposium on Sea Turtle Biology and Conservation

Location

Dalaman, Mugla, Turkey

Event Date

4-19-2015

Keywords

Sea turtles, Hawksbill sea turtles, recreational diving, Honduras

Abstract

Recreational diving is a form of ecotourism that is traditionally viewed as an ecologically sustainable activity prompting increased awareness for the marine environment. Still, recent studies indicate that recreational diving may cause increased spatio-temporal variability within coral ecosystems and unintended behavioral changes in marine macrofauna. Few studies however, have looked specifically at the effect of recreational diving on sea turtles. The purpose of this study was to determine if differences in dive site use and habitat composition can affect the rate of Hawksbill sea turtle (Eretmochelys imbricata) sightings in a marine protected area. From June 3 – August 31, 2014 we collected turtle sightings data from 14 different dive shops within the Roatán marine Park (RMP), a marine protected area around the western tip of the island of Roatán, in the Bay Islands of Honduras. We also collected daily dive logs from 2 dive shops to calculate the rate of turtle sightings per dive for each site. To quantify benthic habitat we conducted habitat transects at 12 different sites within the RMP. For each site, we delineated 6-7 transects at random, and photographed 1m2 quadrants at 5m intervals along a 30m transect. We analyzed habitat data for 10 of the 12 sites using Coral Point Count with Excel Extensions 4.1 (CPCe) and calculated percent abundance and percent coverage for different species. Using ArcMap 10.1, we plotted habitat composition, turtle sighting rate, and number of divers over 4 months for dive sites in the RMP. A total of 644 hawksbill, 406 green (Chelonia mydas), 4 loggerhead (Caretta caretta), and 17 unknown sightings were gathered from 686 dives at 46 dive sites. Total algal abundance within the RMP was high (> 60%) for 5 sites, and moderate (10%) for 9 sites. High algal abundance, however, which can be indicative of degrading habitat, did not correlate with low coral abundance, and turtle sighting rate did not correlate with either metric indicating that algae and coral abundance alone are not adequate predictors of turtle sighting rate. Sightings survey effort was unevenly distributed over the 3 months with peak intensity occurring in July, the height of tourist season. We found a slight positive correlation between the number of divers per visit and the rate of turtle sighting suggesting that more turtles are spotted on dives with more divers. Due to the limited time frame of the study, however, we were unable to determine if this trend was seasonal or not. Based on these preliminary findings, we recommend that long-term studies incorporating sightings from additional dive shops and habitat analysis for more sites, should be conducted in the RMP to determine if diving pressure impacts hawksbill sighting rates.

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