New species of Baleen Whale in the Gulf of Mexico

Bryde's (pronounced “broodus”) whale © NOAA Fisheries

NOAA Fisheries announces scientific research paper that describes a new species of baleen whale in the Gulf of Mexico.

A recently published article in Marine Mammal Science indicates that the whale previously known as the Bryde's (pronounced "broodus") whale is actually a new whale species living in the Gulf of Mexico.

Lead author of the article, NOAA Fisheries scientist Dr. Patricia Rosel, provided the first morphological examination of a complete skull from these whales. She identified diagnostic characteristics that distinguish it from the other closely-related baleen whale species. Genetic data are provided as a second line of evidence supporting the uniqueness of the whales in the Gulf of Mexico. Together, the morphological and genetic data support that these whales represent a new species.

A Journey of Discovery

Dr. Rosel started her journey with the now Rice's whale back in 2008. She and her colleague, NOAA scientist and co-author Lynsey Wilcox, examined the first genetic data obtained from samples collected on NOAA Fisheries vessel surveys in the Gulf of Mexico. They saw that it was quite different from other whales. However, Rosel and fellow NOAA scientist and co-author Dr. Keith Mullin began collaborating on the new species even earlier. Mullin and his colleagues had been studying the whales at sea since the 1990s and believed they were rare and needed protection. These observations prompted NOAA scientists to collect the samples needed to study how closely related these whales were to other whales in the world's oceans.

The process of formally describing a new species takes research, time, collaborations, and reviews by a number of scientific peers. For instance, multiple NOAA staff and collaborating scientists worked over the years to collect field observations and biopsy samples for genetic analyses. These contributions, along with the collaborations described below, provided the pieces needed to unravel a complex species puzzle. Once a scientist is able to collect sufficient evidence to describe a new species, that species receives a Latin name and a "common name." The Latin name for Rice's whale is Balaenoptera ricei.

The name Rice's whale is in honor of renowned American biologist Dale Rice who had a distinguished 60-year career in marine mammal science. He was the first researcher to recognize that Bryde's whales (now Rice's whales) are present in the Gulf of Mexico.

The Skull Reveals More

The most noticeable morphological difference in the new species as compared to its closest relatives is found in the animal's skull. Rosel was able to examine the skull of a Rice's whale in 2020 after one stranded in Florida off Everglades National Park in January 2019. Losses of individuals of a rare species are detrimental to their long-term sustainability. However, when dead stranded animals are recovered by the marine mammal stranding network responders, it provides scientists an opportunity to thoroughly study the animal from top to bottom, inside and out. Numerous members of the Southeast stranding response network were instrumental in collecting the necropsy data and the skeleton from the stranded whale for the morphologic examination.

External body measurements were taken to compare to measurements from other strandings, including those measured by staff with the University of North Carolina at Wilmington from a whale that was previously stranded in North Carolina. The stranding network is composed of cooperating scientific investigators and institutions, volunteer networks authorized by NOAA Fisheries to respond to strandings.

Following the examination and necropsy by NOAA Fisheries biologists and members of the Southeast Marine Mammal Stranding Network, the whale remains were buried. A few months later, a team from the Smithsonian's National Museum of Natural History unearthed the whale remains. They took it for cleaning at the Bonehenge Whale Center in North Carolina and then transported the whale skeleton to their warehouse outside of Washington, D.C.

Last year Dr. Rosel worked with Dr. Tadasu Yamada, a co-author on the study and a scientist from the National Museum of Nature and Science in Japan. They were able to take a closer look at the type specimen of the whale at the Smithsonian and identify differences that distinguish it from other whale species. The morphological differences, when combined with the genetic data Rosel and Wilcox had collected, were enough to distinguish this as a new species of baleen whale.

An Endangered Species

The new species retains its protected status under the Endangered Species Act as it was previously listed as an endangered subspecies (Gulf of Mexico Bryde's whale). It is also protected under the Marine Mammal Protection Act. To date, there are fewer than 100 of these whales remaining, making them critically endangered. If the name Rice's whale is formally accepted by the Society for Marine Mammalogy Committee on Taxonomy, NOAA Fisheries will go through the regulatory process to update the name used in the endangered species listing.

For NOAA scientists, this discovery is exciting and will allow them to better understand and protect this rare baleen whale. Teamwork and collaboration are important throughout this process. NOAA Fisheries truly appreciates the contributions of so many of our research partners. Without building on previous work and the data provided by our fellow scientists, the opportunity to announce a new species would not be possible.

NOAA Partners

• Everglades National Park Service
• Florida Fish and Wildlife Conservation Commission
• University of North Carolina Wilmington
• Mote Marine Laboratory
• Marine Animal Rescue Society
• University of Miami
• Dolphins Plus Marine Mammal Responders

• Rice's whales can weigh up to 60,000 pounds (that is 30 tons), which is about five times as heavy as an elephant!
• They can grow up to 42 feet long.
• Like their sister species, they have lateral three ridges on the top of their rostrum (upper jaw area).
• Not much is known about their life expectancy, but closely related species reach sexual maturity at 9-years-old and can live about 60 years.
• The biggest threats to the species include vessel strikes, ocean noise, energy exploration, development and production, oil spills and responses, entanglement in fishing gear, and ocean debris.
• They are found in the Gulf of Mexico in the Southeast United States.