Gervais' Beaked Whale
About the Species
Gervais’ beaked whales are little known members of the beaked whale family, Ziphiidae. Sometimes called the "Antillean" or "Gulf Stream beaked whale," this species prefers deep tropical, subtropical, and warm temperate waters of the Atlantic Ocean but is occasionally found in colder temperate seas.
There is little information on the abundance of Gervais’ beaked whales worldwide, though they may be the most commonly sighted species of the Mesoplodon genus off the U.S. Atlantic coast and the Gulf of Mexico. They are also the most common Mesoplodon species to strand on the U.S. southeastern Atlantic coast. The beaked whale family is cryptic and skittish, and distinguishing between species in the field can be challenging.
Like all marine mammals, Gervais’ beaked whales are protected under the Marine Mammal Protection Act. They face threats from entanglement in fishing gear and human-caused noise. Gervais’ beaked whales are considered “data deficient” by the International Union for Conservation of Nature list of threatened species, meaning that there is not enough information to assess their population status.
NOAA Fisheries estimates population size for each stock of Gervais’ beaked whale in its stock assessment reports. A stock is a group of animals that occupy the same area and interbreed. There are insufficient data to determine the population trends for this species.
CITES Appendix II
- Throughout Its Range
- Throughout Its Range
Even when dead, many species of beaked whales, especially those in the genus Mesoplodon that includes Gervais’ beaked whales, are very difficult to distinguish from one another because they lack easily discernible or apparent physical characteristics.
As adults, Gervais' beaked whales can reach lengths of about 15 to 17 feet and weigh at least 2,640 pounds. Females may be slightly larger than males. Mature males can be distinguished from females and juveniles by a pair of visible teeth that erupt from the front portion of their bottom jaw. Females and juveniles also have teeth, but they remain hidden beneath the mouth’s gum tissue. Gervais beaked whales typically have straight or slightly curved jawlines.
Gervais' beaked whales have a relatively small to medium-size body with a moderately long beak and an indistinct sloping forehead (or melon). They have a small, triangular, wide-based, slightly hooked dorsal fin located far down the back. Their coloring is dark gray or bluish to black, with a paler ventral side. They tend to become darker as they age. Both females and males often have a pronounced dark patch around the eye. Females and young males may have a series of small, faint, wavy stripes down the centerline of the back. Mature males may also have linear scars from battles over females; however, scarring is generally not heavy with this species.
Behavior and Diet
At sea, Gervais’ beaked whales are challenging to observe and identify to the species level because of their cryptic, skittish behavior; low profile; and a small, inconspicuous blow at the water’s surface. Therefore, much of the available characterization for beaked whales is to the genus level only.
Gervais' beaked whales are usually found individually or in small closely associated social groups. While diving, they use suction to feed mainly on cephalopods (e.g., squid), mysid shrimp, and small fish in deep water.
Lifespan & Reproduction
The estimated lifespan of this species is at least 27 years but may be up to 48 years. Females may become sexually mature at 15 feet. A sexually mature female will give birth to a single newborn calf that is about 7 feet long and weighs about 176 pounds.
Entanglement in Fishing Gear
Gervais' beaked whales have been incidentally taken as bycatch in fishing gear, such as pound nets off the U.S. Atlantic coast (e.g., New Jersey) and potentially in driftnets and gillnets.
This species may be captured in the Caribbean Sea for food.
Deep-diving cetaceans like Gervais’ beaked whales use sound to feed, communicate, and navigate in the ocean. This species may be sensitive to underwater sounds and man-made noise. Sound pollution threatens them by interrupting their normal behavior and driving them away from areas important to their survival, such as feeding and breeding waters.
In the Spotlight
Gervais' beaked whales, like all marine mammals, are protected under the Marine Mammal Protection Act.
Reducing Interactions with Fishing Gear
Gervais’ beaked whales are caught as bycatch in fishing gear, leading to deaths and serious injuries, such as in pound nets off the U.S. Atlantic coast, leading to deaths and serious injuries. NOAA Fisheries is committed to minimizing bycatch in U.S. fisheries to ensure populations are sustainable and to protect species such as the Gervais’ beaked whale.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings including all whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health and determine the best course of action. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes attribute strandings to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and underwater noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Marine Mammal Unusual Mortality Events
Gervais’ beaked whales have never been part of a declared unusual mortality event. Under the Marine Mammal Protection Act, an unusual mortality event is defined as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response." To understand the health of marine mammal populations, scientists study unusual mortality events.
Addressing Ocean Noise
NOAA Fisheries is investigating all aspects of acoustic communication and hearing in marine animals, as well as the effects of sound on beaked whale behavior and hearing. For example, the use of at least some types of shipboard echosounders decreases the acoustic detection rates of multiple species of beaked whales, indicating that they change their behavior when they hear these echosounders. In 2016, we issued technical guidance for assessing the effects of anthropogenic sound on marine mammal hearing.
Like all marine mammals, Gervais’ beaked whales are protected under the MMPA.
Key Actions and Documents
NOAA Fisheries conducts a variety of research on the biology, behavior, and ecology of Gervais’ beaked whales. The results of this research are used to inform management decisions and enhance protection efforts for this species.
Determining the size of Gervais’ beaked whale populations helps resource managers gauge the success of NOAA Fisheries’ conservation measures. Our scientists collect and present these data in annual stock assessment reports.
NOAA Fisheries conducts research cruises to collect information on beaked whale stocks, such as habit preferences and feeding ecology. Information from this research can be used in management actions to protect these animals.
Our research is also focused on acoustics—using underwater sound to learn more about species. We study the basic acoustic behavior of cetaceans and fish, mapping the acoustic environment and finding better ways to study cetaceans using passive acoustic technologies. For example, we tow arrays of hydrophones behind ships to acoustically detect and locate Gervais’ beaked whales during surveys. Using this technology, the Northeast Fisheries Science Center conducted a passive acoustic study to document dive depths of beaked whales, some of which may have been Gervais’ beaked whales. We also use archival bottom-mounted recorders to monitor long-term occurrence of the species at specific recording sites. Our acoustic research also assesses the degree to which human-caused activities are changing the underwater soundscape, how these changes may potentially impact marine animals in their acoustic habitat, and what measures can be taken to mitigate these potential impacts.