The Expert Is In! Gulf of Mexico Bryde’s Whales
Posted: February 13, 2017
Bryde's whale. Credit: NOAA
It is likely that fewer than 100 Bryde’s whales are living in the Gulf of Mexico. NOAA Fisheries' Marine Mammal Branch Chief for the Southeast Regional Office Laura Engleby answers your questions about this rare whale population.
First, how do you pronounce this whale’s name and how did it get that name?
The Bryde’s whale is pronounced “BROO-dus.” The whale was named after the 19th century Norwegian whaler, John Bryde, who was responsible for establishing the first whaling stations in South Africa. These stations were designed to capture whales and sell their oil, blubber, and other parts for money during the whaling era in the 19th and 20th centuries.
Where is the Gulf of Mexico Bryde’s whale located?
While Bryde’s whales are found all around the world, the Gulf of Mexico Bryde’s whale is consistently located along a very narrow depth corridor in the northeastern Gulf of Mexico in the De Soto Canyon area, which is between 300 and 1,000 ft deep. Despite dedicated surveys to search for Bryde’s whales in the continental shelf and oceanic waters of the southeast Atlantic and northern Gulf of Mexico, for the past 20 years they have primarily been found in this very small area. However, historical whaling records suggest that their range was much broader, encompassing the north-central and southern Gulf of Mexico.
What makes the Gulf of Mexico Bryde's whale so unique?
Several things make this whale special:
- They are only year-round resident baleen whale in the Gulf of Mexico. A baleen whale has no teeth and uses baleen plates in their mouth to filter out small prey from seawater.
- Just recently, NOAA Fisheries has determined, using the best available genetic information on the animals, that the Gulf of Mexico Bryde’s whale is genetically distinct from the other two recognized subspecies of Bryde’s whales worldwide. This means that the Gulf of Mexico Bryde’s whale is its own unnamed subspecies.
- Not only are these whales genetically distinct, but they also have very low genetic diversity. Genetic diversity is critical for populations and species to be able to survive by adapting to environmental changes.
What do Bryde’s whales eat and how do they forage?
Little is known about Gulf of Mexico Bryde’s whales foraging ecology. They are thought to feed primarily in the water column on schooling fish such as anchovy, sardine, mackerel, and herring and on small crustaceans. Tracking data from a single whale with an acoustic tag indicates that these animals dive down close to or just above the seafloor and perform foraging lunges on schooling fish, with deep dives occurring during the day and shallower dives at night. When these whales are not foraging on the seafloor, data indicate they spend the rest of their time within 50 feet of the surface.
How many of these whales exist in the Gulf of Mexico?
Scientists believe that there are fewer than 100 Gulf of Mexico Bryde’s whales. This estimate accounts for uncertainty about their existence in the southern Gulf of Mexico, as well as in Mexican and Cuban waters, where there has been less survey effort to look for the whales. The abundance estimate used for the management of the Bryde’s whale stock in the northern Gulf of Mexico is 33 whales. Recently, Duke University researchers estimated abundance to be 44 individuals based on the averages of 23 years of survey data.
What type of threats do Bryde’s whales face?
The most significant threats to Bryde’s whales, in combination with their small population size and limited geographic range, are energy exploration and development, oil spills and response, vessel strikes, and anthropogenic noise. These threats could be devastating for the small population of Bryde’s whale living in the Gulf of Mexico. Other threats that could affect them include harmful algal blooms, fishing gear entanglements, and military activities.
What is NOAA Fisheries doing to protect these whales?
The Gulf of Mexico Bryde’s whale is currently protected under the Marine Mammal Protection Act. However, in order to preserve the remaining population and aid in the species’ recovery, NOAA has announced a proposed rule to list the Gulf of Mexico Bryde’s whale as endangered under the Endangered Species Act. The proposed rule was published in December 2016. Before making a final decision on this proposal, we are asking for comments from the public, other governmental agencies, the scientific community, industry, and any other interested parties. These comments will be considered and addressed, and then a final decision will be made to complete or withdraw the listing.
Learn more about Bryde's whales and celebrate Whale Week with NOAA Fisheries.