Northern GOM Bryde's Whale
The Northern Gulf of Mexico Bryde’s whale (pronounced BROO-dus) is the only year-round resident baleen whale in the northern Gulf of Mexico. The Gulf of Mexico population is estimated at 33 animals and is genetically distinct from other populations found in the Pacific, Indian, and Atlantic oceans, making it potentially one of the most endangered of the baleen whales. They are found primarily off the panhandle of Florida, in an area known as De Soto Canyon.
Bryde’s whales occur in tropical and subtropical waters of the Atlantic, Pacific, and Indian oceans. Bryde’s whales were targeted by commercial whalers in the 1900’s, after many other large whale species became depleted. Between 1911 and 1987, over 30,000 Bryde’s whales were caught worldwide.
Bryde’s whales in U.S. waters have been divided into three stocks: Eastern Tropical Pacific, Hawaiian, and Northern Gulf of Mexico. Although Bryde’s whales are relatively common in some regions, those in the Northern Gulf of Mexico stock are estimated to number only about 33. They occur along the shelf break in waters 100 to 400 meters deep in the De Soto Canyon region of the northeastern Gulf of Mexico, off the Florida Panhandle. Genetic analyses have determined that the Gulf of Mexico stock is distinct from Bryde’s whale stocks in other parts of the world, and it has a very low level of genetic diversity. Based on genetics analyses and new morphological information, scientists have proposed that the Gulf of Mexico Bryde’s whale be recognized as a distinct species (Balaenoptera ricei) with the new name Rice’s whale. That proposal is currently under review.
Bryde’s whales in the Gulf of Mexico are currently threatened by vessel strikes, acoustic disturbance from seismic airguns and other oil and gas-related activities, military activities, vessel noise, oil spills, and pollution from agricultural runoff. Commercial fishing with longline and trap gear also overlaps to a limited degree with Bryde’s whale habitat.
A petition was submitted to the National Marine Fisheries Service (NMFS) in 2014 to list the Northern Gulf of Mexico stock as endangered under the Endangered Species Act (ESA). NMFS subsequently initiated a status review of Bryde’s whales under the ESA, which was finalized in December 2016. The status review determined that the Gulf of Mexico Bryde’s whale is taxonomically a subspecies of the Bryde’s whale, thus meeting the ESA’s definition of a species. Based on the Gulf of Mexico Bryde’s whale’s small population (likely fewer than 100 individuals), its life history characteristics, its extremely limited distribution, and its vulnerability to existing threats, NMFS has determined that the Gulf of Mexico Bryde’s whale is in danger of extinction throughout all of its range. In April 2019, NMFS listed the Gulf of Mexico Bryde’s whale as endangered throughout its range. The listing was based on the species’ small population size, restricted range, and threats due to energy exploration, development, and production, oil spills and oil spill response, vessel collisions, fishing gear entanglements, and human-caused sound. The immediate next steps would be the development of a recovery plan and designation of critical habitat under the ESA.
What the Commission Is Doing
The Marine Mammal Commission is working with NMFS and other partners in the Gulf of Mexico to expand research and monitoring efforts for all marine mammals.
In April 2015, the Commission held a meeting to identify high priority, overarching data needs and to identify potential funding sources and opportunities for expanding marine mammal research and monitoring in the Gulf.
Commission staff serve as one of two technical monitors on a RESTORE Act Science Program-funded project to evaluate Trophic Interactions and Habitat Requirements of Gulf of Mexico Bryde’s Whales. The timeframe for the project is June 2017 to May 2020. Field studies will include shipboard surveys, passive acoustic monitoring, tagging, prey characterization using echosounders and net tows, and collection of biological samples. The focus of the field work would be on primary habitat in the eastern Gulf, but the spatial scope could be expanded to other potential habitat areas. Expected outcomes include an improved understanding of population status, identification of habitat features and characteristics (including critical habitat primary constituent elements), and a better understanding of the risk of exposure to human activities in the Gulf.
Commission Reports and Publications
Gulf of Mexico Marine Mammal Research and Monitoring Meeting Summary (Marine Mammal Commission 2015)
|Letter Date||Letter Description|
|October 31, 2018|
|August 21, 2018||
Letter to NMFS regarding application submitted by the Bureau of Ocean Energy Management (BOEM) seeking issuance of regulations for taking of marine mammals incidental to geophysical surveys in the Gulf of Mexico under section 101(a)(5)(A) of the Marine Mammal Protection Act (MMPA)
|February 6, 2017|
|December 4, 2015|
|September 28, 2015|
|July 9, 2013|
|July 8, 2013|
|December 28, 2012|
The Northern Gulf of Mexico Bryde’s whale is currently threatened by collisions with vessels, acoustic disturbance from seismic airguns and other oil and gas-related activities, military activities, vessel noise, oil spills, and pollution.
Bryde’s whale sightings in the Gulf of Mexico are rare, as are strandings. On 29 January 2019, a 38-foot male Bryde’s whale stranded in the Florida’s Everglades. A necropsy of the whale determined that the whale was underweight and examination of its stomach revealed a piece of hard plastic, approximately 5 cm by 7.5 cm in size. The plastic piece had sliced through part of the whale’s stomach, which likely contributed to its death. The whale’s skeleton is now at the Smithsonian Institution in Washington, D.C., where scientists will use it as a “type specimen” for the species.
Current Conservation Efforts
In September 2014, NMFS received a petition to list the Northern Gulf of Mexico Bryde’s whale stock under the Endangered Species Act (ESA). NMFS subsequently issued a notice announcing its determination that the petition was warranted, which prompted a status review of the stock to determine if the stock should be listed. The status review was finalized in December 2016 and determined that the Gulf of Mexico Bryde’s whale is taxonomically a subspecies of the Bryde’s whale, thus meeting the ESA’s definition of a species. Based on the Gulf of Mexico Bryde’s whale’s small population (likely fewer than 100 individuals), its life history characteristics, its extremely limited distribution, and its vulnerability to existing threats, NMFS has determined that the Gulf of Mexico Bryde’s whale is in danger of extinction throughout all of its range. NMFS issued a proposed rule to list the Gulf of Mexico Bryde’s whale as endangered and reviewed comments received on the proposed listing, including comments submitted by the Commission. In April 2019, NMFS issued a final rule to list the Gulf of Mexico Bryde’s whale as endangered.
The Future/Next Steps
Now that NMFS has finalized the listing, the immediate next step would be designation of critical habitat under the ESA. In the interim, additional information regarding abundance, distribution, diet, habitat use, and stock structure and status in relation to other Bryde’s whale stocks would assist in the designation of critical habitat and the development of a recovery plan outlining strategies to conserve and protect this stock from natural and human-caused threats. The number of species/stocks of Bryde’s whales in other parts of the world is still under study.