Guidelines for Oil Spill Response and Natural Resource Damage Assessment: Sea Turtles

May 21, 2019

These guidelines provide an in-depth review of considerations for response and NRDA for sea turtles and incorporates knowledge gained from previous oil spills, especially the 2010 Deepwater Horizon (Macondo 252) spill within the northern Gulf of Mexico. Included in this document are essential tools and information pertinent to sea turtles found within U.S. waters to aid preparations for future oil spills, promote an effective spill response, and facilitate damage assessment.

NOAA Technical Memorandum NMFS-OPR-61

Sea turtles are vulnerable to oil spills on land and at sea. All six species found within U.S. and territorial waters are listed as threatened or endangered under the Endangered Species Act of 1973, as amended (16 USC § 1531 et seq.). Sea turtles have complex life histories and rely on a variety of habitats that may be negatively affected by oil and response to oil spills. Effective response to oil spills and assessment of injury under Natural Resource Damage Assessment (NRDA), as provided by the Oil Pollution Act of 1990, should integrate the unique biology of each species and consider the specific risks to each life stage. Oil on nesting beaches can affect adult female turtles, eggs, and hatchlings, whereas sea turtles of all sizes, from hatchlings to adults, can be exposed to oil at sea. Smaller life stages of turtles (i.e., post-hatchlings and oceanic phase juveniles) spend much of their time at the surface and associate with oceanographic features that tend to accumulate oil, making them especially at-risk during some spills. Exposure to oil and dispersants occurs via direct contact, inhalation, or ingestion. Many of the demonstrated effects of oil on sea turtles are related to physical fouling. High rates of oil ingestion documented during previous spills and high risk of inhalational exposure are concerns with regard to toxicological effects. Response activities, such as controlled burns, shoreline cleaning, oil boom deployment, use of dispersants, oil skimming, and vessel traffic, pose additional hazards.


Effective response to oil spills requires early identification of species and life stages at risk, timely deployment of knowledgeable personnel and other assets, efficient preparation of emergency responders, and judicious collection of information that will only be available during and shortly following a spill. These measures also are critical for informing a damage assessment. Tools available to understand the magnitude of potential injuries to sea turtles as a result of an oil spill include: surveys of nesting beaches and marine habitats (e.g., vessel-based and aerial) to document sea turtle presence, abundance, and oil exposure; evaluation of oiled turtles and nests encountered during rescue efforts, stranding response, and other activities to document exposure and effects (including those caused by response activities); and for larger spills, integration of field observations, remote sensing data, and other information over time to evaluate the magnitude and persistence of injuries to sea turtles and their habitats.

Last updated by Office of Protected Resources on 05/22/2019