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Description:
Title:
Densities and drivers of sea turtle populations across Pacific coral reef ecosystems
Alternate Title:
Densities and drivers of sea turtle populations across Pacific coral reef ecosystems
Author(s):
Becker, Sarah L.
Brainard, Russell E.
Van Houtan, Kyle S.
United States. National Marine Fisheries Service,
Pacific Islands Fisheries Science Center (U.S.),
Office of Habitat Conservation (U.S.)
United States, National Oceanic and Atmospheric Administration,
Coral Reef Conservation Program (U.S.)
National Marine Protected Areas Center (U.S.)
Corporate Name:
United States. National Marine Fisheries Service,
Pacific Islands Fisheries Science Center (U.S.),
Office of Habitat Conservation (U.S.)
United States, National Oceanic and Atmospheric Administration,
Coral Reef Conservation Program (U.S.)
National Marine Protected Areas Center (U.S.)
Dates of Publication:
2019
Abstract:
Sea turtle populations are often assessed at the regional to sub-basin scale from discrete indices of nesting abundance. While this may be practical and sometimes effective, widespread in-water surveys may enhance assessments by including additional demographics, locations, and revealing emerging population trends. Here, we describe sea turtle observations from 13 years of towed-diver surveys across 53 coral islands, atolls, and reefs in the Central, West, and South Pacific. These surveys covered more than 7,300 linear km, and observed more than 3,400 green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) sea turtles. From these data, we estimated sea turtle densities, described trends across space and time, and modelled the influence of environmental and anthropogenic drivers. Both species were patchily distributed across spatial scales, and green turtles were 11 times more abundant than hawksbills. The Pacific Remote Island Areas had the highest densities of greens (3.62 turtles km(-1), Jarvis Island), while American Samoa had the most hawksbills (0.12 turtles km(-1), Ta'u Island). The Hawaiian Islands had the lowest turtle densities (island ave = 0.07 turtles km(-1)) yet the highest annual population growth (mu = 0.08, sigma = 0.22), suggesting extensive management protections can yield positive conservation results. Densities peaked at 27.5 degrees C SST, in areas of high productivity and low human impact, and were consistent with patterns of historic overexploitation. Though such intensive surveys have great value, they are logistically demanding and therefore have an uncertain budget and programmatic future. We hope the methods we described here may be applied to future comparatively low-cost surveys either with autonomous vehicles or with environmental DNA.
Keywords:
Conservation biology
Science
Sea turtles
Technology
Temperature
Place Keywords:
United States
Local Corporate Name:
NMFS (National Marine Fisheries Service)
PIFSC (Pacific Islands Fisheries Science Center)
OHC (Office of Habitat Conservation)
CoRIS (Coral Reef Information System)
MPA (Marine Protected Areas)
Type of Resource:
Journal Article
Note:
Sea turtle populations are often assessed at the regional to sub-basin scale from discrete indices of nesting abundance. While this may be practical and sometimes effective, widespread in-water surveys may enhance assessments by including additional demographics, locations, and revealing emerging population trends. Here, we describe sea turtle observations from 13 years of towed-diver surveys across 53 coral islands, atolls, and reefs in the Central, West, and South Pacific. These surveys covered more than 7,300 linear km, and observed more than 3,400 green (Chelonia mydas) and hawksbill (Eretmochelys imbricata) sea turtles. From these data, we estimated sea turtle densities, described trends across space and time, and modelled the influence of environmental and anthropogenic drivers. Both species were patchily distributed across spatial scales, and green turtles were 11 times more abundant than hawksbills. The Pacific Remote Island Areas had the highest densities of greens (3.62 turtles km(-1), Jarvis Island), while American Samoa had the most hawksbills (0.12 turtles km(-1), Ta'u Island). The Hawaiian Islands had the lowest turtle densities (island ave = 0.07 turtles km(-1)) yet the highest annual population growth (mu = 0.08, sigma = 0.22), suggesting extensive management protections can yield positive conservation results. Densities peaked at 27.5 degrees C SST, in areas of high productivity and low human impact, and were consistent with patterns of historic overexploitation. Though such intensive surveys have great value, they are logistically demanding and therefore have an uncertain budget and programmatic future. We hope the methods we described here may be applied to future comparatively low-cost surveys either with autonomous vehicles or with environmental DNA.
Grant no. e0214972
URL:
DOI:
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