Harnessing Recreational Divers for the Collection of Sea Turtle Data Around the Cayman Islands

Abstract

Here we present data from a 26-month program "Caribbean Turtle Watch," initiated as part of the "Turtles in the Caribbean Overseas Territories" (TCOT) program and designed to harness recreational divers to assess in-water populations of marine turtles in the Cayman Islands. We recorded 521 dives in Grand Cayman and Little Cayman between September 1, 2002 and November 29, 2003. Data, presented as the mean number of turtles sighted per dive, provide insight into spatiotemporal patterns of sightings as a proxy of abundance. Widespread sightings were recorded of two marine turtle species, green turtles Chelonia mydas and hawksbill turtles Eretmochelys imbricata, around both islands. There was no obvious relationship between the existence of Marine Protected Areas (MPAs) and the abundance of turtle sightings. Diving is allowed in Marine Park Zones and dive pressure may impact overall habitat quality in these areas. The vast majority of sightings of both species (94% in each case) were considered to be juvenile or subadults. While turtle sighting potential was not a major influence on dive site choice, actual turtle sighting greatly enhanced dive enjoyment. Spatiotemporal and morphological analyses of data collected by volunteers compared favorably with those based on data collected by scientists. This technique is transferable to other countries and may hold particular value in areas where resources assigned to marine turtle research are low.