Global Atlas User Guide
In SWOT Report, vol. 20, you will find articles that describe the status of sea turtle regional management units (RMUs) in six of the world’s major ocean basins. Each article is followed by a detailed two-page overview of that region’s eight RMUs. Each of the eight RMU insets (as depicted below) includes a map showing the overall distribution of turtles from that RMU and their known nesting beaches, as well as detailed information about the RMU’s conservation status, primarily from the CPP publication. The following diagram explains how to interpret the information provided on each inset.
For more information on IUCN Red List status, visit www.iucnredlist.org. For more information about CPP assessment status, visit SeaTurtleStatus.org/atlas-references.
RMU Maps
The 48 RMU maps in this Atlas incorporate data from more than 6,200 nesting sites (including 339 key nesting sites) for the six sea turtle species that were included in the most recent RMU and CPP analyses: green, hawksbill, leatherback, olive ridley, Kemp’s ridley, and loggerhead. The nesting data were sourced from SWOT/OBIS-SEAMAP; see seaturtlestatus.org/atlasreferences for data citations.
Known nesting sites are indicated by black dots, while key nesting sites (those with nesting abundance in the top 5% of their RMU, or more than 1,000 clutches in the most recent year for which data are available) are shown as crosses. When other nesting data types were provided, conversion factors (ranging from 2.2 to 5.0 clutches per female and from 0.55 to 0.81 crawls per clutch) were used to convert the provided data into an estimated number of clutches.
Risk and Threat Charts
A risk/threat matrix, like the one shown here, appears at the top of each region’s two-page overview of RMU status. It illustrates where the region’s RMUs fall on the spectrum of risk and threat. The y-axis (vertical) depicts overall threat, and the x-axis (horizontal) depicts risk. Each numbered dot on the matrix corresponds to the RMU of the same number listed below it, and is colored according to species. Dots that fall in the upper right quadrant represent RMUs that are high-risk, high-threat, whereas those in the lower left quadrant are low-risk, low-threat; RMUs in the other quadrants are high-risk, low-threat (lower right) or low-risk, high-threat (upper left). In the example to the left, the region had six RMUs scored as low-risk, low-threat (lower left); one RMU (#6) as high-risk, low-threat (lower right); and one RMU (#7) as high-risk, high-threat (upper right).
Risks and Threats Defined
The CPP scores for each RMU are based on expert evaluations of relative risks and threats. Risk is defined by CPP as the overall viability of a population, specifically those characteristics that make an RMU more or less resilient to negative impacts. For example, high abundance, increasing trends, and high genetic diversity are considered to make an RMU more resilient and healthy, whereas those with low abundance and declining trends are more vulnerable. Threats are assessed based on their relative impact on an RMU’s abundance, measured in terms of adult-equivalent mortality. Threats that affect adults carry greater weight than those impacting hatchlings or juveniles.
This article originally appeared in SWOT Report, vol. 20 (2025). Download this entire article as a PDF.