Marine Mammals & Sea Turtles

Marine Mammals & Sea Turtles

Green turtle
Green turtle. Photo credit: Mark Sullivan/NOAA.

29 species (28 cetaceans and 1 manatee) of marine mammals are found in the Gulf of Mexico.

The Cetaceans include minke, sperm, pygmy sperm, dwarf sperm, Cuvier’s beaked, Blainville’s beaked, and killer whales, as well as Risso’s, bottlenose, rough-toothed, pantropical spotted, spinner, striped, and Fraser’s dolphins. Several of these species are protected as either threatened or endangered under the Endangered Species Act (ESA). All whales and dolphins in the Gulf are protected under the Marine Mammal Protection Act (MMPA)

The only Gulf Serenia is the West Indian manatee which is generally found in the coastal bays of Florida. The West Indian manatee is also listed as endangered under the ESA.

The Gulf is also home to five species of sea turtles: green turtle, hawksbill turtle, Kemp’s ridley turtle, leatherback turtle and loggerhead turtle. All Gulf sea turtles are listed as either endangered or threatened under the ESA. 
GRN works to ensure that these at risk marine species are protected by:

  • Protecting important coastal bays, marshes, swamps, and other habitats; and
  • Reducing threats to sea turtles and marine mammals posed by fishing, and offshore oil and gas exploration and development. 

Marine Mammals and the Impacts of Oil and Gas Exploration 

To search for oil and gas, the industry typically uses arrays of high-powered airguns that release intense blasts of compressed air into the water every 10-12 seconds, for weeks or months at a time. The noise they produce is almost as intense as dynamite. Each year, industry routinely conducts dozens of airgun or seismic surveys in the northern Gulf, one of the most highly prospected bodies of water on the planet. 

Whales, dolphins, and other ocean species depend on sound to feed, mate, navigate, maintain social bonds and undertake other activities essential to their survival. Airgun noise is loud enough to mask whale calls over thousands of miles, destroying their capacity to communicate and breed. It has been shown to drive whales to go silent, abandon their habitat and cease foraging. Closer in, it can cause hearing loss, injury and potentially death

Seismic surveys have continued since the BP drilling disaster, and are known to affect marine mammal populations within the spill zone. These populations include the Gulf’s coastal bottlenose dolphins, which have undergone a severe die-off since the spill; its resident population of Bryde’s whales, of which fewer than 50 individuals are believed to remain; and its small population of sperm whales, whose nursery in Mississippi Canyon was ground zero for the spill. 

In 2010, Gulf Restoration Network, the Center for Biological Diversity, the Natural Resources Defense Council, and the Sierra Club filed a lawsuit asserting that the U.S. Department of the Interior failed to satisfy basic requirements of the Marine Mammal Protection Act and Endangered Species Act in permitting seismic exploration in the Gulf, and failed to prepare an environmental impact statement, as required by the National Environmental Policy Act (NEPA). 

In June 2013, that groups settled that suit. The settlement agreement is a landmark for marine mammal protection in the Gulf, securing new protections for whales and dolphins harmed by deafening airguns, and establishing a process for investigating alternatives to airgun surveys, while the government undertakes the required environmental review of seismic exploration in the Gulf.  The settlement establishes (1) prohibitions on airgun blasting in biologically important areas, such as the DeSoto Canyon, and airgun exploration in coastal waters during the main calving season for bottlenose dolphins; (2) mandatory minimum separation distances between surveys; and (3) a requirement that passive acoustic listening devices be used to detect and avoid marine mammals during times of reduced visibility.