Rice's Whale

Rice’s Whale

The Rice’s whale is NOAA Fisheries’ newest Species in the Spotlight. This initiative is a strategic approach to endangered species recovery that focuses on highly at-risk species for which immediate, targeted actions can halt their decline and stabilize their populations.

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Scientists have known that these medium-sized baleen whales occur in the Gulf of America (formerly Gulf of Mexico) for decades. For most of that time, the whales were believed to be a subpopulation of Bryde’s whale, which occur in other temperate and tropical waters around the globe. After years of research, a team of scientists demonstrated in 2021 that Rice’s whales are genetically and morphologically distinct from Bryde’s whales. Rice’s whale is in fact a unique whale species that is only known to reside in the Gulf of America. The species was named in honor of Dale W. Rice, the first scientist to write about the whales in 1965.

Rice's whales grow to longer than 40 feet and weigh up to 30 tons. Like Bryde’s whales, Rice’s whales have three parallel ridges on top of their head. This feature distinguishes them from sei, fin, and minke whales, which have a single rostral ridge. They are uniformly gray on top, with a pale to pink belly, and have a strongly hooked dorsal fin. Acoustic research has shown that Rice’s whales communicate using unique vocalizations, or calls, which can be detected with passive acoustic monitoring devices.

NOAA Fisheries listed the Rice’s whale (then known as the Gulf of Mexico Bryde’s whale) as an endangered species under the Endangered Species Act in 2019. Rice’s whales are also protected under the Marine Mammal Protection Act and are considered depleted. The species’ small population size and high extinction risk make it a priority for NOAA Fisheries and our partners to recover.

Where Rice’s Whales Live

Rice’s whales are only known to reside in the Gulf of America, where they live year-round. Most sightings have been concentrated in the northeastern Gulf off the West Coast of Florida. They have also been seen and heard in the western Gulf offshore of Louisiana and Texas. Areas of predicted habitat exist in the southern Gulf, along the shelf break of Mexico. Rice's whale calls were recently detected offshore of Tampico, but the extent to which the whales inhabit Mexican waters is unknown. Records of “finback whales” from whaling logbooks in the 18th and 19th centuries suggest Rice’s whales may have been more widely distributed throughout the Gulf of America historically. Rice's whales have stranded along the U.S. Atlantic coast, but no sightings or calls of Rice's whales have been confirmed outside of the Gulf of America.

Population Status

The species likely numbers fewer than 100 individuals, making it among the most endangered species of whale in the world. The most recent abundance estimate from 2017–2018 surveys in the eastern Gulf of America is approximately 50 individuals. Rice’s whales are one of the marine mammal species that was most heavily impacted by the Deepwater Horizon oil spill. A modeling study conducted after the spill estimated that 48 percent of Rice’s whale habitat in the eastern Gulf was exposed to oil. The population declined by as much as 22 percent compared to its pre-spill size. Few calves have been seen during surveys since 2010. There have been frequent observations of individual whales in poor body condition, suggesting there may be lingering effects on reproduction and population growth.

Habitat

Most visual sightings and acoustic detections of Rice’s whales have occurred along the Gulf of America shelf break, in waters that are 100–400 meters deep. Recent tagging and foraging studies indicate the whales dive toward the seafloor during daylight hours. They seek out high-energy prey fish, like the silver-rag driftfish, which occur in large schools along the bottom. At night, the whales appear to spend most of their time near the surface, a behavior that could place them at greater risk of vessel strikes.

Threats

The Gulf of America is highly industrialized and impacted by many human activities. These activities can pose risks to Rice’s whales and their habitat through:

• Vessel strikes
• Noise from vessels and energy exploration
• Oil spills and other pollutants, including lingering effects of the Deepwater Horizon oil spill
• Ingestion of and entanglement in marine debris
• Climate change and its effect on prey
• Entanglement in fishing gear

The species’ low genetic diversity, small population size, and restricted range further reduces its resilience to threats.

Examples of Threats

In 2009, an adult female Rice’s whale was struck and killed by a ship. Her body was carried into Tampa Bay draped across the ship’s bow. Researchers determined that she was lactating at the time of her death. If she was nursing a calf, her calf probably also died, during or after the strike. In 2019, NOAA scientists photographed a free-swimming Rice’s whale with a severely deformed spine that was likely caused by a vessel strike. In that same year, an adult male Rice’s whale died after ingesting marine debris and washed ashore in southwest Florida. These three observed deaths represent only a fraction of actual mortalities. It is difficult to effectively monitor deaths of Rice’s whales because the whales live far from shore, and we do not regularly conduct surveys in their known habitat.

Species Recovery

We have made tremendous strides in our understanding of Rice’s whales in a short period of time. Several challenges still complicate Rice’s whale recovery, such as:

• Gaps in our scientific knowledge about Rice’s whale life history, demographics and distribution
• Understanding how existing and emerging human activities impact Rice’s whales and their habitat, and how to reduce those impacts
• Limited awareness about the species amongst the public and regional stakeholders

To begin addressing these challenges NOAA Fisheries released a Rice’s Whale Recovery Outline in 2020. It serves as an interim conservation strategy until a full recovery plan is developed. The recovery outline summarizes the key factors that are known (and unknown) about their:

• Biology
• Population status
• Primary threats
• Conservation actions taken to date

It also establishes an interim recovery strategy and action plan, including actions that are needed for research, outreach, and to manage threats.

In 2021, we hosted a virtual, multi-session Rice’s Whale Recovery Planning Workshop (PDF, 49 pages) to gather information, facts, and perspectives on how to recover Rice’s whales. Participants included federal and state agencies, scientific experts, commercial fishery representatives, conservation partners, and non-governmental organizations. Information gleaned from the workshop is being considered as NOAA Fisheries develops the Rice’s Whale recovery plan. We will also be developing a Species in the Spotlight Priority Action Plan to identify priority activities over the next 5 years, which will complement the recovery planning effort.