Impacts of Recreational Diving on Hawksbill Sea Turtles (Eretmochelys imbricata) in the Roatán Marine Park, Honduras: Summer 2014

This report represents the ongoing work of the Protective Turtle Ecology Center for Training, Outreach, and Research, Inc. (ProTECTOR Inc.) in Honduras during the 2014 season and is provided in partial fulfillment of research agreements with the Roatán Marine Park

Impacts of Recreational Diving on Hawksbill Sea Turtle (Eretmochelys imbricata) Behaviour in a Marine Protected Area

The hawksbill sea turtle (Eretmochelys imbricata) is a critically endangered species encountered by recreational divers in marine protected areas (MPAs) circumtropically. Few studies, however, have examined the impacts of recreational diving on hawksbill behaviours. In 2014, we collected turtle sightings surveys and dive logs from 14 dive operations, and conducted in-water observations of 61 juvenile hawksbill turtles in Roatán, Honduras, to determine if differences in dive site use and diver behaviours affected sea turtle behaviours in the Roatán Marine Park. Sightings distributions did not vary with diving pressure during an 82-day study period. We found the amount of time turtles spent eating, investigating and breathing decreased when approached by divers. Our results suggest diver interactions may negatively impact sea turtle behaviours, however it is unknown if recreational diving has a cumulative effect on turtles over time. We recommend that MPA managers should implement monitoring programmes that assess the impacts of tourism on natural resources. We have established monitoring of hawksbills as representatives of the marine habitat in an MPA, which has the potential to be heavily impacted by dive tourism, and provide recommendations for continued monitoring of the resource

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

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 (\u3e 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

HotSpotter: Using a Computer-Driven Photo-ID Application to Identify Sea Turtles

© 2020 Elsevier B.V. Photo identification (PID) in animal studies has been a widely used method for identifying individuals of many species based on unique natural markings and patterns. The use of PID has facilitated investigations in which residency, home ranges, and growth rates have been assessed. However, many PID studies in the past have relied heavily on manual photo matching. More recently, computer-assisted PID programs have been used to identify individuals of different sea turtle species, and reduced time investment in identifying individuals within specific populations. Still, some computer-based PID programs require significant time investment in ensuring photos are captured at consistent angles and lighting conditions, pre-processing image manipulations, and post-processing manual matching confirmation of potential matches provided by the program. For PID to be an effective time and money saving mechanism for wildlife research and conservation, these common drawbacks need to be addressed with a computer-assisted PID program that reduces manipulation and time investment burden, and consistently provides accurate and reliable results. In this study, we evaluated the accuracy of matching individual face images using the HotSpotter (HS) PID program by building a database of 2136 images of hawksbill (Eretmochelys imbricata) turtles, then querying the database with 158 new images to find matches for individual turtles. Overall, we found that with almost no pre-processing manipulation, and with images from highly variable underwater conditions, qualities, and angles, HS correctly matched individuals in the first choice 80% of the time, increasing to 91% in the first six choices. When assessing in-water images only, accuracy for matching increased from 84% in the first choice, to 94% by the sixth choice. We suggest that the integration of HS technology into a global, web-based PID system will increase the ability to remotely identify individual marine organisms on a global scale, and improve usability for community scientists who may have little to no technical training