False killer whales are social animals found globally in all tropical and subtropical oceans and generally in deep offshore waters. Learn more about the false killer whale.
False Killer Whale
Pseudorca crassidens
Protected Status
ESA Endangered
Main Hawaiian Islands Insular DPS
MMPA Protected
Throughout Its Range
MMPA Depleted
Main Hawaiian Islands Insular stock
CITES Appendix II
Throughout Its Range
SPAW Annex II
Throughout the Wider Caribbean Region
Quick Facts
Weight
Up to about 3,000 pounds
Length
Up to 16 feet (females) and 20 feet (males)
Lifespan
Up to 63 years (females) and 58 years (males)
Threats
Competition with fisheries,
Environmental contaminants,
Fishery interactions/bycatch,
Hunting (outside United States)
Region
Alaska,
Pacific Islands,
Southeast,
West Coast
False killer whale jumping out of the water in the Northwestern Hawaiian Islands. Credit: Jim Cotton
False killer whale jumping out of the water in the Northwestern Hawaiian Islands. Credit: Jim Cotton
About the Species
False killer whale jumping out of the water in the Northwestern Hawaiian Islands. Credit: Jim Cotton
False killer whale jumping out of the water in the Northwestern Hawaiian Islands. Credit: Jim Cotton
The false killer whale is a large member of the Delphinidae family, or dolphins. Members of this family include all dolphin species, as well as other larger species, such as killer whales, long-finned and short-finned pilot whales, whose common names also contain "whale" instead of "dolphin."
False killer whales are social animals found globally in all tropical and subtropical oceans. In tropical and subtropical seas, false killer whales occur in a wide range of habitats, in both open oceans and insular waters.
Fishery interactions are one of the main threats facing this species. False killer whales are known to depredate (take fish and bait off of fishing lines), which can lead to hooking and/or entanglement.
The main Hawaiian Islands insular false killer whales are the only endangered population of false killer whales in the United States. Their range is remarkably limited, living within approximately 45 miles of the 7 populated Hawaiian Islands. Long-term commitments across state and international borders are needed to stabilize global false killer whale populations.
NOAA Fisheries has responsibilities for promoting the recovery of false killer whales. Our scientists and partners use a variety of innovative techniques to study this species. We also work with our partners to develop regulations and management actions that conserve false killer whales and their food sources, decrease contaminants in oceans, reduce ocean noise, and raise awareness about the whales and the actions people can take to support their recovery.
Population Status
The broad distribution of false killer whale populations makes it difficult to estimate the global population size of this species. Scientific studies in the Pacific Islands Region have revealed different populations—some of which may be distinct species or subspecies.
Hawaiʻi is the home to the most well-studied false killer whale populations. Three populations or stocks of false killer whales occur in Hawaiʻi: the endangered main Hawaiian Islands insular population, the Northwestern Hawaiian Islands population, and the pelagic population.
Main Hawaiian Islands Insular Population
The current abundance estimate for the endangered main Hawaiian Islands insular false killer whale DPS is approximately 140 individuals. We estimate that the insular population has been decreasing by approximately 3.5 percent per year for at least the last 10 years. The cause of decline is unknown, but it is thought to be partially due to interactions with fisheries, especially before 1990 when longline fishing was more common in the nearshore waters of Hawaiʻi. More recently, evidence suggests—based on high rates of dorsal fin and mouthline injuries—that fisheries interactions represent one of the most significant threats to this population. This threat may also act in tandem with other threats, such as exposure to pollutants and reduced genetic diversity.
Northwestern Hawaiian Islands Population
The Northwestern Hawaiian Islands population of false killer whales is not well-studied. Current population estimates can be found in the latest NOAA Fisheries marine mammal stock assessment reports.
Hawaiʻi Pelagic Population
The Hawaiʻi pelagic population of false killer whales is estimated to be roughly 2,000 individuals. NOAA Fisheries collected data from ship-based, line-transect surveys within the central Pacific Ocean between 1986 to 2017 and used a model-based approach to estimate the current population size. Their historical population size is also unknown, though interactions with longline fisheries are known to have killed or seriously injured animals in this population since at least the late 1990s. While there have been several ship-based surveys within and beyond Hawaiian waters, low sighting rates and changes in survey design (intended to provide more precise estimates given the social structure and behavior of false killer whales) make it difficult to determine trends in abundance for this pelagic population.
The Palmyra Atoll, American Samoa, eastern North Pacific, northern Gulf of America, and western North Atlantic populations of false killer whales are not as well-studied. Current population abundance estimates for all stocks can be found in the latest NOAA Fisheries marine mammal stock assessment reports.
Appearance
False killer whales are dark gray, often appearing black on all but a small part of their ventral (underside) surface, which is lighter between the pectoral fins running from the throat down to the belly.
The species is large and slender, and males are slightly larger than females. They have a small conical head without a beak. The front of an adult male’s head hangs over the lower jaw to a greater extent than in females and is flattened in older males.
The pectoral fins or flippers have a distinct central hump creating an S-shape along the outer edge. The dorsal fin is located in the middle of the back and generally curves backward. Dorsal fin shapes show a lot of variability, often caused by injury.
Adult females reach lengths of 16 feet, while adult males are almost 20 feet long. In adulthood, large false killer whales can weigh up to 3,000 pounds.
Scientists can photo-identify individual whales through unique natural markings, such as scars on false killer whales’ dorsal fins or scars from cookie cutter shark bites. These prominent markings to the body and dorsal fin help distinguish one whale from another.
Behavior and Diet
False killer whales are gregarious and form strong social bonds. They are often found in relatively small subgroups of a single to a few individuals that are associated with larger aggregations—known as clusters—that may spread over tens of kilometers. These strong social bonds between groups and dispersion into small subgroups likely help them find prey.
False killer whales are top predators that primarily hunt fish and squid. They feed both during the day and night. When they capture prey, many individuals tend to converge, and their prey items may be shared among several animals in the cluster. In Hawaiʻi, these clusters may include 40 to 50 animals, whereas larger groups have been observed in other regions. They are known to strand in their social groups as well. In some regions, false killer whales are also found with other cetaceans (whales and dolphins), most notably bottlenose dolphins.
False killer whales can dive for up to 18 minutes and swim at high speeds to capture prey at depths of 984 to 1,640 feet. They often leap completely out of the water, particularly when attacking certain prey species. In Hawaiʻi, they are also known to throw fish high into the air before consuming them.
Where They Live
False killer whales occur in tropical, subtropical, and temperate waters of all ocean basins. In the United States, they are found around Hawaiʻi, in all Pacific Remote Island Areas, the Mariana Archipelago, and in American Samoa, as well in the Gulf of America and in the warm Gulf Stream waters off the East Coast. False killer whales have been observed off the U.S. West Coast as far north as British Columbia, Canada, typically during warmer oceanographic regimes.
World map providing approximate representation of the false killer whale range.
False killer whales generally prefer offshore tropical to subtropical waters that are deeper than 3,300 feet. However, data has shown that some populations of false killer whales reside close to the Hawaiian Islands forming distinct island-associated populations (e.g., main Hawaiian Islands insular false killer whales and Northwestern Hawaiian Islands false killer whales). This is likely due to the islands’ unique oceanographic setting, which concentrates and aggregates prey.
Hawaiian Populations
While the ranges for most false killer whale populations are not well described, the three Hawaiian populations are better understood and complex. The ranges of these populations partially overlap, but despite this, they do not socially interact and breed with one another.
Range map for the three populations of false killer whales in Hawai'i, including the endangered main Hawaiian Islands insular population, Northwestern Hawaiian Islands population, and the pelagic population. Credit: NOAA Fisheries
All three populations overlap in the offshore waters surrounding Kauaʻi and Niʻihau islands (starting roughly 15 kilometers/9 miles off the coast). Beyond this area, each population occupies a distinct range:
Main Hawaiian Islands Insular Population - This endangered population remains close to the main islands and is rarely seen more than 70 kilometers (45 miles) from shore.
Northwestern Hawaiian Islands Population - Inhabits a 58-mile boundary around the Northwestern Hawaiian Islands and Kauaʻi and Niʻihau islands. Its range lies entirely within the pelagic population boundary and overlaps with the insular population only near Kauaʻi and Niʻihau.
Hawaiʻi Pelagic Population -Encompasses deep, open-ocean waters surrounding both the main Hawaiian Islands and the Northwestern Hawaiian Islands. These false killer whales usually remain offshore, however, data suggests that they are not unlikely to approach closer than 15 kilometers (9 miles) to shore.
Lifespan & Reproduction
The oldest estimated age of false killer whales (based on growth layers in teeth) is 63 years for females and 58 years for males.
Female false killer whales reach sexual maturity between the ages of 8 and 11, while males mature 8 to 10 years later. Gestation ranges from 11 to 16 months, and lactation occurs for 1.5 to 2 years. Time between births is unknown but is estimated to be around 7 years. Female false killer whales enter menopause and become less reproductively successful between 44 and 55 years old. Species known to undergo menopause include humans, killer whales, false killer whales,beluga whales, narwhals, short-finned pilot whales, and likely, bottlenose dolphins. Drawing from our biological understanding of these species, it is plausible that other long-lived marine mammals may also experience menopause.
Threats
Fishery Interactions
Bycatch occurs when false killer whales take (or depredate) bait and catch off fishing lines. This action can result in incidental take—unintentional hooking and/or entanglement—as well as serious injury and/or death. This is especially a concern for false killer whales that interact with longline fisheries.
In addition, false killer whales primarily hunt fish and squid. Many of the species they eat are the same ones that fisheries target. This is particularly true in the Pacific, where preferred fish for both false killer whales and consumers are tuna, billfish, wahoo (ono), and mahimahi. The overlap creates a direct competition for food between fisheries and false killer whales.
Environmental Contaminants
False killer whales are long-lived, upper-trophic-level predators—they are near the top of the food chain—so they accumulate high levels of contaminants from the marine environment. Exposure to harmful contaminants in the marine environment, including persistent organic pollutants (e.g., industrial chemicals and pesticides) and heavy metals, can result in a number of biological effects to marine mammals, such as diseases and reproductive issues. It can also affect the quality and quantity of false killer whales’ prey. Although the United States has restricted or phased out the production and use of many of these harmful chemical contaminants, some continue to be used in other regions of the world and can be transported through the atmosphere or by ocean currents.
Hunting
False killer whales are hunted in other parts of the world, including Indonesia, Japan, and the West Indies.
Scientific Classification
Kingdom
Animalia
Phylum
Chordata
Class
Mammalia
Order
Cetacea
Family
Delphinidae
Genus
Pseudorca
Species
crassidens
What We Do
Conservation & Management
We have focused our conservation efforts to help rebuild endangered and depleted populations in the Central North Pacific. Targeted management actions include:
Our research projects have discovered new aspects of false killer whale biology, behavior, and ecology. This helps us better understand the threats false killer whales face. It also informs management decisions for all false killer whales and enhances recovery efforts for the endangered main Hawaiian Islands false killer whale DPS. Our work includes:
Performing stock assessments to gather population information
Researching false killer whale social structure
Collaborating with scientists to track the movements and behavior of Hawaiian false killer whales.
Identifying high-use areas of habitat in the main Hawaiian Islands
Acoustically monitoring the Hawaiʻi-based longline fishery for interactions with false killer whales
Conducting necropsies on stranded false killer whales
Be responsible when viewing marine life in the wild. To ensure the safety of all small whales, maintain a minimum distance of at least 50 yards and limit your observation time to 30 minutes or less.
Report all sick, injured, entangled, stranded, or dead animals to make sure professional responders and scientists are informed and can take appropriate actions. Numerous organizations around the country are trained and ready to respond. Never approach or try to save an injured or entangled animal yourself—it can be dangerous to both the animal and you.
Call the NOAA Fisheries Enforcement Hotline at (800) 853-1964 to report a federal marine resource violation. This hotline is available 24 hours a day, 7 days a week for anyone in the United States.
Do not harass, feed, hunt, capture, kill, pursue, approach, surround, swim with, or attempt to touch protected marine wildlife. Never entice protected marine wildlife to approach you.
Do not engage, chase, or try to get a reaction from the animal. Disturbing wildlife interrupts their ability to perform critical functions such as feeding, breeding, nursing, resting, and socializing.
If you’re on a vessel and a marine animal approaches you, put the engine in neutral and allow the animal to continue on its way.
Featured News
A group of melon-headed whales swimming together on February 1, 2026, seen during the Winter Hawaiian Islands Cetacean and Ecosystem Assessment Survey. Credit: NOAA Fisheries/Mary Applegate, taken under NOAA permit #25754.
The main Hawaiian Islands insular false killer whale distinct population segment (DPS) is the only endangered population of false killer whales in the world. It is also the population we know the most about. They reside within the main Hawaiian Islands, moving widely and quickly while sticking close to the populated islands. They do not socialize or breed with other populations of false killer whales. These often cryptic and acrobatic residents are known to throw fish and leap high into the air during foraging attempts.
A variety of threats jeopardize their survival. Evidence suggests—based on high rates of dorsal fin and mouthline injuries—that fisheries interactions/bycatch represent one of the most significant threats to the population. This threat may also act synergistically with other threats, such as exposure to pollutants and reduced genetic diversity. The population continues to struggle and has been decreasing by an estimated 3.5 percent per year for the last 10 years.
A resident false killer whale surfaces just offshore of the main Hawaiian Islands. Credit: NOAA Fisheries
Where They Live
This endangered population of island-associated false killer whales only resides within the offshore and coastal waters of the main Hawaiian Islands (Hawaiʻi Island to Niʻihau), staying within approximately 50 miles of the islands year-round. Their greatest offshore movements occur on the leeward (western) sides of the islands, where individuals tend to spread out over much larger areas, both near and far from shore. When on the windward (eastern) sides, individuals concentrate closer to shore, heavily using areas in the approximately 1,500- to 4,000-feet depth range, particularly north of Hawaiʻi Island, Maui, and Molokaʻi. Movements between islands may occur over the course of a few days, moving from the windward to leeward side and back within a day. On July 24, 2018, NOAA Fisheries published a final rule to designate critical habitat for main Hawaiian Islands insular false killer whales in waters from the 45-meter depth contour to the 3,200-meter depth contour around the main Hawaiian Islands from Ni'ihau east to Hawai’i.
Map depicting false killer whale stock boundaries for the Northwestern Hawaiian Islands stock and the Main Hawiian Islands insular stock.
The range of main Hawaiian Islands insular false killer whales partially overlaps with the ranges of the Hawaiʻi pelagic and Northwestern Hawaiian Islands populations. However, genetic data analyses, photo-identification, and social network analyses indicate that this population consists of a tight social network. It is unconnected with the other two Hawaiian populations. In fact, the population can also be broadly divided into four social clusters, with mating occurring primarily, though not exclusively, within these clusters. This may further constrict the already limited gene flow within the population. We continue to learn more about their movements, social structure, and range through dedicated and collaborative research efforts.
Population Status
NOAA Fisheries scientists estimate that the current main Hawaiian Islands insular false killer whale population numbers only 139 individuals. We do not have historical population estimates, though spotter planes in the late 1980s observed large aggregations of 350 to 400 whales in a single area.
Scientific surveys since then suggest that the population declined at an average rate of 9 percent per year through at least the early 2000s. Current data suggests that the population has been decreasing by an estimated 3.5 percent per year since 2013. The cause of this population’s decline is unknown, but it may be partially due to interactions with fisheries, especially before 1990 when longline fishing was more common in the nearshore waters of Hawaiʻi.
The population of endangered false killer whales faces a variety of threats. These include fisheries interactions/bycatch, small population size, and contaminants, among several others. They have a high rate of dorsal fin injuries and mouthline injuries, likely caused by efforts to take bait and catch from fishing lines. Recent research suggests that the majority of the small population is interacting and competing with fisheries that operate within their range.
The small size of this endangered population poses a unique threat to this group. Within a small, highly social population, the potential for reduced genetic diversity increases, potentially making the population more vulnerable to diseases or other environmental changes. Such environmental events may further harm the population by causing a genetic bottleneck. This is a reduction in the variation of the gene pool that only rebounds when the population breeds with other populations or enough random genetic mutations have accumulated over many generations. Such a small population may also suffer from a breakdown of cooperative feeding if an aggregation is not large enough to find adequate food.
Past research has shown that some of the most important threats facing these whales, such as sound and high contaminant levels, require long-term solutions. For example, the threat of contaminants is challenging, particularly because the whales remain contaminated by chemicals that were restricted or phased out of production in the United States decades ago. Some mysteries also persist. For example, are there health issues, like disease or fecundity issues, that we have not yet uncovered? Will increases in prey abundance benefit the resident whales, or will any increases be consumed by other predators? We also must consider new threats and actions as we look to a future with environmental change, new alternative ocean energy projects, and continuing development along our coasts and in our ports. In the next 5 years, we have several high-priority projects planned to help answer these remaining questions and inform management actions to advance recovery.
Collectively, these efforts aim to address key threats such as fishery interactions, habitat degradation, and critical data gaps concerning the biology and recovery needs of insular false killer whales.
The main Hawaiian Islands are home to an endangered population of resident false killer whales. Credit: NOAA Fisheries
Strategic Recovery Planning Under the ESA
Under the Endangered Species Act, NOAA Fisheries is required to develop and implement recovery plans for the conservation and survival of listed species. We are committed to the protection and recovery of the main Hawaiian Islands insular false killer whale. Our goal is helping this endangered population recover from its very low population size. This would allow the population to be reclassified from endangered to threatened and ultimately be removed from the list of threatened and endangered species.
Recovery Outline
The ESA mandates that NOAA Fisheries develop and implement recovery plans for the conservation and survival of ESA-listed species under its jurisdiction. In September 2016, we developed a recovery outline to systematically and cohesively guide recovery actions for the endangered main Hawaiian Islands insular false killer whale until we completed a recovery plan.
Recovery Planning Workshop
In October 2016, we held a recovery planning workshop. The purpose of the workshop was to:
Review and update the original threats analysis from the 2012 final listing rule and the 2010 Status Review Report
Identify potential recovery criteria and actions to address the threats to the main Hawaiian Islands insular false killer whale
Participants included federal and state agencies, scientific experts, commercial and recreational fishermen, conservation partners, and nongovernmental organizations.
In addition to using recovery planning guidance, we based this plan on an updated recovery planning approach developed by the U.S. Fish and Wildlife Service and adopted by NOAA Fisheries as an updated approach to our traditional recovery plans. This approach makes recovery planning more efficient and effective. It also creates a more dynamic and flexible plan. The recovery planning components are divided into three independent parts: a recovery status review, a recovery plan, and a recovery implementation strategy.
Recovery Status Review
Using the 2010 Status Review Report for the endangered main Hawaiian Islands insular false killer whale as a foundation, we developed an up-to-date Recovery Status Review for the species. The Recovery Status Review is a stand-alone document that provides all the detailed information on the species' biology, ecology, status and threats, and conservation efforts to date. This document was published in October 2020 and updated in August 2021. We will update it as necessary with new information and use it for various purposes, including 5-year reviews, Section 7 consultations, and Section 10 conservation plans.
Recovery Plan
We published a Draft Recovery Plan for the endangered main Hawaiian Islands insular false killer whale in October 2020 and a Final Recovery Plan in November 2021. The Final Recovery Plan recommends the following recovery actions:
Ensure population abundance, trend, and number of social groups meet or exceed target levels
Address threats from fisheries including incidental take and competition with fisheries for prey
Address threats from environmental contaminants and biotoxins
Address threats from anthropogenic noise
Better understand the effects of environmental changes and manage accordingly
Ensure that regulatory mechanisms, including state and federal management and post-delisting monitoring, are in place
Ensure that secondary threats and synergies among threats are not limiting recovery of the population
Recovery Implementation Strategy
Lastly, we published a Draft Recovery Implementation Strategy for the endangered main Hawaiian Islands insular false killer whale in October 2020 with an updated version of the Recovery Implementation Strategy published in November 2021. This document is a flexible, operational document that NOAA Fisheries and partners use to assist in planning and implementing activities to carry out the recovery actions in the Recovery Plan. The stepped-down recovery activities identified in the Recovery Implementation Strategy can be adapted or modified as the science evolves. This affords us the ability to modify these activities in real time to reflect changes in the information available, as well as progress towards recovery.
All documents used to inform the recovery of the endangered main Hawaiian Islands insular false killer whale including the Recovery Status Review, Recovery Plan, and Recovery Implementation Strategy underwent peer review. We accepted and considered public comments on both the Draft Recovery Plan and Draft Recovery Implementation Strategy before finalizing the recovery plan and recovery implementation strategy in November 2021.
Research projects have illuminated new aspects of false killer whale biology, behavior, and ecology and helped us better understand the challenges this resident population faces. Since 2012, NOAA Fisheries has implemented a range of management actions under the Endangered Species Act and Marine Mammal Protection Act to better protect this population. These include:
Designating critical habitat to protect the essential areas insular false killer whales rely on for feeding, breeding, and movement between the main Hawaiian Islands
Publishing a comprehensive recovery plan and implementation strategy, providing a clear roadmap for recovery actions necessary to address threats and promote the long-term survival of the species
Incorporating reasonable and prudent measures into federal fishery and military operations through ESA Section 7 consultations to reduce impacts of these actions
Providing funding for the cetacean stranding program and specialized research efforts at universities like the University of Hawai'i Manoa, as well as state-led research and threat reduction efforts via NOAA Fisheries’ Species Recovery Grants to States Program
Establishing a False Killer Whale Take Reduction Plan that includes protective measures, such as prohibiting longline fishing in designated areas around the main Hawaiian Islands
Collectively, these efforts aim to address key threats such as fishery interactions, habitat degradation, and critical data gaps concerning the biology and recovery needs of insular false killer whales.
In addition, new information on distribution and habitat use, gathered from both acoustic monitoring and satellite tagging, have informed updated abundances estimates and trend data for these whales. Satellite tags are shedding light on the fecundity, habitat use, distribution and foraging behavior of the whales. Our scientists and collaborators are conducting research into health, habitat use, and understanding body condition changes over time and places with prey limitations to inform the need for additional conservation actions.
NOAA Fisheries works to protect all populations of false killer whales, focusing primarily on recovery of the endangered main Hawaiian Islands insular population and Hawaiian pelagic population—to support this, we have taken steps to reduce incidental serious injury and death of false killer whales in the Hawaiʻi-based deep-set and shallow-set longline commercial fisheries.
Recovery Planning and Implementation
Recovery Action
Under the ESA, NOAA Fisheries develops and implements recovery plans for the conservation and survival of listed species. A final recovery plan for the endangered main Hawaiian Islands insular false killer whale DPS was published in 2021.
False killer whales swimming in the ocean waters off Rota, the southernmost island of the Commonwealth of the Northern Mariana Islands. Credit: NOAA Fisheries
Implementation
The ESA authorizes NOAA Fisheries to appoint recovery teams to help develop and implement recovery plans. Rather than convening a recovery team for the endangered main Hawaiian Islands insular false killer whale, we use an open public process to engage as many interested stakeholder groups and individuals as possible and work with a variety of partners to implement the actions in the recovery plan.
Once a species is listed under the ESA, NOAA Fisheries evaluates and identifies whether any areas meet the definition of critical habitat. Those areas may be designated as critical habitat through a rulemaking process. The designation of an area as critical habitat does not create a closed area, marine protected area, refuge, wilderness reserve, preservation, or other conservation area; nor does the designation affect land ownership. Federal agencies that undertake, fund, or permit activities that may affect these designated critical habitat areas are required to consult with NOAA Fisheries to ensure that their actions do not adversely modify or destroy designated critical habitat.
In 2018, NOAA Fisheries designated critical habitat under the ESA for the endangered main Hawaiian Islands insular false killer whale in waters from 45 meters to 3,200 meters (49 to 3,500 yards) in depth surrounding the main Hawaiian Islands (from Ni’ihau to Hawai’i Island). This designation does not include most bays, harbors, or coastal in-water structures. We designated this habitat because it contains four physical and biological features essential to the conservation of the whales:
Adequate space for movement and use within shelf and slope habitat
Prey species of sufficient quantity, quality, and availability to support individual growth, reproduction, and development, as well as overall population growth
Waters free of pollutants of a type and amount harmful to the species
Sound levels that would not significantly impair false killer whales’ use or occupancy of their habitat
In April 2022, we published a 5-year review (PDF, 16 pages) that determined that the main Hawaiian Islands insular false killer whale DPS should remain listed as endangered. We will continue to reexamine the status once every 5 years to address new information available on this species. Our ultimate goal is to recover the main Hawaiian Islands insular false killer whale DPS to the point where the species no longer needs protection under the ESA.
False killer whale spyhopping in the waters off the island of Rota. Spyhopping is a behavior where a whale or dolphin raises its head vertically straight up out of the water to look around above the surface. Credit: NOAA Fisheries
Conservation Efforts
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states and the Hawaiian islands to respond to marine mammal strandings. 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.
False killer whales have never been part of a declared unusual mortality event. Under the MMPA, 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.
Reducing Bycatch in Hawaiʻi Pelagic Longline Fisheries
Bycatch in fishing gear is a leading cause of false killer whale deaths and injuries. NOAA Fisheries established a take reduction team to recommend measures to reduce deaths and serious injuries of false killer whales in Hawaiʻi-based deep-set and shallow-set longline fisheries. We published a final take reduction plan in 2012, based on the take reduction team's recommendations, which includes gear requirements (“weak” circle hooks and strong branch lines) in the deep-set longline fishery, longline fishing closure areas, training and certification for vessel owners, captains, and crew in marine mammal handling and release, captains’ supervision of marine mammal handling and release, and posting of placards on longline vessels to aid in species identification and handling and release techniques. We also develop research priorities to support the plan’s implementation and inform development of potential future amendments, and we monitor its progress toward achieving MMPA goals.
Oil Spills and Response Preparation in the Hawaiian Islands
To minimize the effect of a potential spill on seals, sea lions, whales and dolphins, NOAA developed Pinniped and Cetacean Oil Spill Response Guidelines. False killer whales, including the endangered main Hawaiian Islands insular DPS, are at risk of harm in the event of an oil spill. To reduce the risk of a spill, NOAA fisheries along with our state and federal partners have developed response plans.
Learn more about oil spill response preparedness in Hawaiʻi:
Conducting field work to address false killer whales’ spatial and temporal habitat use
Analyzing overlap between insular false killer whales and Hawaiʻi state fisheries
Investigating and responding to strandings
Providing targeted outreach to specific fishers, boaters, and tour operators to mitigate or reduce interactions with false killer whales; improve species identification to complement research; and increase public reporting of strandings
In 2009, NOAA Fisheries received a petition (PDF, 29 pages) to list the main Hawaiian Islands insular false killer whale as an endangered species and designate critical habitat under the ESA.
Notice of availability; Recovery Plan for Main Hawaiian Islands Insular False Killer Whale Distinct Population Segment and associated Recovery Implementation Strategy for this species.
Notice of Availability of Draft Recovery Plan and Draft Recovery Implementation Strategy, and Notice of Initiation of a 5-Year Review for the main Hawaiian Islands insular false killer whale distinct population segment.
On July 24 2018, NOAA Fisheries publishes a final rule to designate critical habitat for the main Hawaiian Islands insular false killer whale (Pseudorca crassidens) distinct population segment (DPS) by designating waters from the 45-meter depth contour to
In response to a petition from the Natural Resources Defense Council, we, NOAA Fisheries, issue a final determination to list the Main Hawaiian Islands insular false killer whale (Pseudorca crassidens) distinct population segment (DPS) as an endanger
Incidental Take Authorization: Lamont-Doherty Earth Observatory's Marine Geophysical Survey of the East Pacific Rise in the Eastern Tropical Pacific Ocean
Incidental Take Authorization: U.S. Navy's Surveillance Towed Array Sensor System Low Frequency Active Sonar Systems Testing in the Western and Central North Pacific and Eastern Indian Oceans
NOAA Fisheries conducts research on the biology, behavior, ecology, and genetics of false killer whales, with a particular focus on the three populations of Hawaiian false killer whales. We use the results of this research to inform management decisions, further direct scientific research, and enhance conservation and recovery efforts for the species.
In collaboration with fishermen of the Hawaiʻi longline deep-set fishery, we conduct research to investigate interactions between false killer whales and fishing gear. We deploy small, autonomous acoustic recorders on longline fishing gear to acoustically monitor fishing sets for the presence of false killer whales. We compare the acoustic presence of false killer whales to fishing activity and depredation rates (taking bait off fishing lines) to assess vessel and gear sounds and false killer whale occurrence and behavior around gear, as well as to identify potential acoustic cues.
Our scientists and collaborators collect observations of whales and dolphins following line-transect protocols. Observers continuously search for animals using 25x150 "big-eye" binoculars to scan 180° forward of the ship. When they spot whales or dolphins, the visual team identifies the species and each observer independently estimates the number of animals in the group.
The notches on the trailing edge of the dorsal fin of the false killer whale on the right form a unique pattern, allowing this individual to be identified each time it is photographed. Credit: Cascadia Research Collective/Robin W. Baird
Identifying Whales Using Environmental DNA
The name eDNA derives from the collection method—essentially, we are detecting the DNA of an individual as it passes through the environment and sheds small bits of tissue, such as sloughed skin. Water samples for eDNA research are routinely collected during NOAA Fisheries ship surveys.
Acoustic Science
Passive Acoustic Surveys
Sound travels much farther than light in water, and cetaceans (whales and dolphins) commonly use sound rather than vision to communicate with each other and find food. Just as cetaceans listen for each other and for their prey, we can listen to their sounds to locate groups of these animals.
Surveying with Stationary and Drifting Acoustic Recorders
We have broadly used autonomous (no human intervention needed) stationary and drifting acoustic recorders to understand the distribution and seasonality of cetaceans throughout the world’s oceans. Our scientists maintain a network of seafloor-anchored passive acoustic listening stations and deploy drifting acoustic buoys to listen for cetaceans and understand ocean noise.
Ocean Noise Reference Stations
To monitor ocean noise, NOAA has deployed acoustic monitoring stations throughout U.S. waters that together make up the Ocean Noise Reference Station Network. One of these stations is located approximately 100 miles north of Oʻahu.
Determining the size of false killer whale populations helps resource managers determine the success of conservation measures and regulations. Our scientists collect population information on false killer whales from various sources and present the data in annual stock assessment reports.
In this study, we used photo-identification data over a 23 year period to reassess the number and membership of social clusters for false killer whales.
The Passive Acoustic Ecology Program conducts research projects that use passive acoustics to assess populations and improve our understanding of cetaceans in the Gulf of America and U.S. waters of the Western Atlantic.
The Passive Acoustic Ecology Program conducts research projects that use passive acoustics to assess populations and improve our understanding of cetaceans in the Gulf of America and U.S. waters of the Western Atlantic.
