About the Species
The killer whale, also known as orca, is one of the top marine predators. It is the largest member of the Delphinidae family, or oceanic dolphins. Members of this family include several species, including long-finned pilot whales and short-finned pilot whales, whose common names contain "whale" instead of "dolphin."
Found in every ocean in the world, they are the most widely distributed of all whales and dolphins. Scientific studies have revealed many different populations with several distinct ecotypes (or forms) of killer whales worldwide—some of which may be different species or subspecies. They are one of the most recognizable marine mammals, with their distinctive black and white bodies. Killer whales can adapt to almost any condition, and occur in both open seas and coastal waters. Taken as a whole, the species has the most varied diet of all cetaceans (whales and dolphins), but different populations are usually specialized in their foraging behavior and diet. They often use a coordinated hunting strategy, working as a team like a pack of wolves.
Hunters and fishermen once targeted killer whales. As a result, historical threats to killer whales included commercial hunting, and culling to protect fisheries from killer whales. In addition, although live capture of killer whales for aquarium display and marine parks no longer occurs in the United States, it continues to remain a threat globally. Today, some killer whale populations face many other threats, including food limitations, chemical contaminants, and disturbances from vessel traffic and sound. Efforts to establish critical habitat, set protective regulations, and restore prey stocks are essential to conservation, especially for endangered killer whale populations.
All killer whale populations are protected under the Marine Mammal Protection Act. Only two populations receive special protections under federal law:
- Southern Resident population (listed as endangered under the Endangered Species Act).
- AT1 Transient population (listed as depleted under the MMPA).
Southern Resident killer whales are the only endangered population of killer whales in the United States, ranging from central California to southeast Alaska. Long-term commitments across state and national borders are needed to stabilize the Southern Residents’ population and prevent their extinction. The Southern Resident killer whale is one of NOAA Fisheries' Species in the Spotlight. This initiative includes animals considered most at risk for extinction and prioritizes recovery efforts.
NOAA Fisheries is committed to the conservation of killer whales and the protection and recovery of endangered populations. Our scientists and partners use a variety of innovative techniques to study and protect them. We also work with our partners to develop regulations and management plans that protect 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.
Several different populations and ecotypes of killer whales are found throughout the world. NOAA Fisheries estimates population size in our stock assessment reports. It is estimated that there are around 50,000 killer whales globally. Approximately 2,500 killer whales live in the eastern North Pacific Ocean—home to the most well-studied killer whale populations.
In recent decades, several populations of killer whales have declined and some have become endangered. The population of AT1 Transients, a subgroup of Transient killer whales in the eastern North Pacific, has been reduced from 22 to 7 whales since the 1989 Exxon Valdez oil spill. In 2004, NOAA Fisheries designated this group as depleted under the MMPA based on the results of the status review (PDF, 25 pages).
Scientists estimate the minimum historical population size of Southern Residents in the eastern North Pacific was about 140 animals. Following a live-capture fishery in the 1960s for use in marine mammal parks, 71 animals remained in 1974. Although there was some growth in the population in the 1970s and 1980s, with a peak of 98 animals in 1995, the population experienced a decline of almost 20 percent in the late 1990s, leaving 80 whales in 2001. The population census at the end of 2016 counted only 78 whales, and several deaths in 2017 brought the total of this struggling population to 76. In 2003, NOAA Fisheries began a research and conservation program with congressional funding to address the dwindling population. Southern Residents were listed as endangered in 2005 under the ESA and a recovery plan (PDF, 1.7MB) was completed in 2008.
- Southern Resident DPS
- Throughout Its Range
- AT1 Transient stock
Killer whales are black on top with white undersides and white patches near the eyes. They have a gray or white saddle behind the dorsal fin. These markings vary widely between individuals and populations. Adult males develop larger pectoral flippers, dorsal fins, tail flukes, and girths than females.
Behavior and Diet
Killer whales are highly social, and most live in social groups called pods (groups of related individuals seen together more than half the time). Individual whales tend to stay in their original pods. Pods typically consist of a few to 20 more more animals, and larger groups sometimes form for temporary social interaction, mating, or seasonal concentration of prey.
Killer whales rely on underwater sound to feed, communicate, and navigate. Pod members communicate with each other through clicks, whistles, and pulsed calls. Each pod in the eastern North Pacific possesses a unique set of calls that are learned and culturally transmitted among individuals. These calls maintain group cohesion and serve as family badges.
Although the diet of killer whales depends to some extent on what is available where they live, it is primary determined by the culture (i.e., learned hunting tactics) for each ecotype of killer whale. For example, one ecotype of killer whales in the U.S. Pacific Northwest (called Residents) exclusively eats fish, mainly salmon, and another ecotype in the same area (Transients, or Bigg’s killer whales) primarily eats marine mammals and squid.
Killer whales often use a coordinated hunting strategy and work as a team to catch prey. They are considered a top predator, eating near the top of the food chain.
Where They Live
Killer whales are found in all oceans. While they are most abundant in colder waters like Antarctica, Norway, and Alaska, they are also found in tropical and subtropical waters. The most well-studied killer whale populations occur in the eastern North Pacific Ocean. Resident killer whales have been seen from California to Russia. Transient killer whales occur throughout the eastern North Pacific, and are often seen in coastal waters. Their habitat sometimes overlaps with Resident and Offshore killer whales. Offshore killer whales have the largest range of any community, and often occur more than 9 miles offshore.
Lifespan & Reproduction
Male killer whales typically live for about 30 years, but can live from 50 to 60 years. Females typically live about 50 years, but can live from 80 to 90 years.
Females reach sexual maturity when they are between 10 and 13 years old. They are typically pregnant for 15 to 18 months and give birth to a single calf. Calves nurse for at least a year. There is no distinct calving season, so birth can take place in any month. The birth rate for killer whales is not well understood. In some populations, birth rate is estimated at every 5 years for an average period of 25 years. Killer whales, short-finned pilot whales, and humans are the only known species that go through menopause.
Lack of Food
Overfishing and habitat loss have decreased the amount of prey available to some killer whales. Without enough prey, killer whales might experience decreased reproductive rates and increased mortality rates. This threat is especially important for Southern Resident killer whales because some populations of their preferred prey, Chinook salmon, are also threatened or endangered.
Contaminants enter ocean waters and sediments from many sources, such as wastewater treatment plants, sewer outfalls, and pesticide application. Once in the environment, these substances move up the food chain and accumulate in top predators. Killer whales accumulate these contaminants in their bodies because of their long lifespan, position at the top of the food chain, and blubber stores. These pollutants can harm killer whales’ immune and reproductive systems.
Despite modern pollution controls, chemical contamination through the food chain continues to threaten killer whales. These controls have reduced, but not eliminated, many contaminants in the environment. Additionally, some of these contaminants persist in the marine environment for decades and continue to threaten marine life.
The 1989 Exxon Valdez oil spill in Prince William Sound was strongly correlated with the direct loss of individuals. However, oil spills can also have an indirect impact on killer whales by impacting the abundance of prey species. In addition, the bioaccumulation of certain pollutants such as PCBs in the food web can be seen in apex predators like killer whales—and particularly among the transient population.
Disturbance from Vessels and Sound
When vessels are present, killer whales hunt less and travel more. Noise interference from vessels, as well as from industrial and military activities, interrupts killer whales’ ability to use sound, which in turn disturbs their feeding, communication, and orientation. Increased vessel noise causes Southern Resident killer whales to call louder, expending more energy in the process.
Killer whales were once considered monotypic (belonging to one species). But many biologists now believe that several populations, or even subspecies, of killer whales exist.
There are three main types of killer whales: Resident, Transient, and Offshore. Each ecotype differs in appearance, diet, habitat, genetics, and behavior. While all three types share at least part of their habitats, they are not known to interbreed with each other.
Resident Killer Whales
Resident killer whales have rounded dorsal fins and a wide variety of “saddle” markings on the patch behind their dorsal fins. They range from California to Russia and live in large groups. Four populations of Resident killer whales occur in the Pacific Northwest:
- Southern residents.
- Northern residents.
- Southern Alaska residents.
- Western Alaska North Pacific residents.
Resident killer whales usually eat different varieties of salmon. Southern Resident killer whales prefer Chinook salmon, some of which are endangered.
Transient Killer Whales
Transient killer whales have straighter dorsal fins and only two types of saddle markings. They live throughout the coastal waters of the Northwest in small groups. Transient killer whales’ diets are more varied and can include seals, porpoises, sea lions, and other whales.
Offshore Killer Whales
Offshore killer whales have rounded fins and are generally smaller than the other types of killer whales. They have the largest range and can occur up to 9 miles offshore. Offshore killer whales eat fish, and sometimes sharks.
In addition to the three types, distinct populations of killer whales exist throughout the world. Populations are smaller groups within each type of killer whale. For example, there are four different populations of Resident killer whales. Each population has its own unique diet, behaviors, social structure, and habitat.
Killer Whale Social Structure and Behavior
Some populations of killer whales have even more specialized diets. Off the coast of Norway, killer whales feed mainly on herring and other schooling fish. In waters off New Zealand, some killer whales eat stingrays and sharks. In Antarctic waters, killer whales eat minke whales, seals, or Antarctic toothfish.
Killer whales are highly social and live in pods—large groups of whales that are seen together over half the time. Individual whales tend to stay in their original pods. Pods typically consist of two to 15 animals, but larger groups sometimes form for temporary social interaction, mating, or seasonal availability of food. Pods differ in size due to behavioral differences, the availability of food, and the number of whales living in a given area.
Pod members communicate with each other through underwater sounds such as clicks, whistles, and pulsed calls. Each pod in the Pacific Northwest possesses a unique set of sounds that are learned and culturally transmitted among individuals. These sounds help keep groups together and serve as family badges.
Pods also work together to hunt. They use a coordinated hunting strategy and work as a team to catch prey. This ability makes killer whales a top predator.
In the Spotlight
Southern Resident Killer Whale
The Southern Resident killer whale is one of NOAA Fisheries’ Species in the Spotlight. This initiative is a concerted agency-wide effort to spotlight and save the most highly at-risk marine species.
The endangered Southern Resident is an icon of the Pacific Northwest and inspires widespread public interest, curiosity, and awe around the globe. Southern Residents are also among the most contaminated marine mammals in the world.
The population census at the end of 2016 counted only 78 Southern Resident killer whales. In 2003, NOAA Fisheries began a research and conservation program with congressional funding, and the Southern Residents were listed as endangered in 2005 under the Endangered Species Act. A recovery plan was completed in 2008.
The population continues to struggle and has declined over 10 percent since 2005. We have come a long way in our understanding and ability to protect this unique population, and in 2014 we summarized a decade of research and conservation activities in a special report.
Where Southern Resident Killer Whales Live
During the spring, summer, and fall, the range of Southern Resident killer whales includes the inland waterways of Washington State and the transboundary waters between the United States and Canada. We know less about their winter movements and range. They have been spotted as far south as central California during the winter months and as far north as Southeast Alaska. In recent years we have learned much more about their coastal habitat use through our Northwest Fisheries Science Center's satellite tagging work.
Scientists estimate the minimum historical population of Southern Residents numbered about 140 animals. Following a live-capture fishery in the 1960s, 71 animals remained in 1974. Although there was some growth in the population in the 1970s and 1980s, with a peak of 98 animals in 1995, the population experienced a decline of almost 20 percent in the late 1990s, leaving 80 whales in 2001.
Noise and overcrowding from boat traffic, as well as a scarce supply of their preferred food—salmon—pose serious threats to this endangered population. It is hoped that focused efforts and critical investments within NOAA Fisheries, and continued engagement with our vital partners, will stabilize and prevent the Southern Resident killer whale’s extinction. Past research has shown that some of the most important threats facing the whales, such as prey limitation and high contaminant levels, cannot be addressed without a long-term commitment. Recovery of threatened salmon, for example, is a monumental task in itself and is expected to take many years.
The threat of contaminants is also challenging, particularly because the whales remain contaminated by chemicals that were banned decades ago. Some mysteries also persist. For example, will increases in salmon abundance benefit the Southern Resident whales, or will any increases be consumed by other salmon predators? Are there health issues, like disease, that we have not yet uncovered? We also must consider new threats and actions as we look to a future with climate change, new alternative ocean energy projects, and continuing development along our coasts and in our ports. In the next 5 to 10 years, several high-priority projects are planned to help answer these remaining questions and inform management actions to advance recovery.
New information on coastal distribution and habitat use, gathered from both acoustic monitoring and satellite tagging, will inform designation of additional critical habitat for the whales. Seasonal health assessments, habitat use, times and places with prey limitations, and vessel impacts that affect health or feeding will all be taken into consideration when determining the need for additional conservation actions.
With more than 10 years of funding, collaboration, and ingenuity we have taken substantial and important steps to aid Southern Resident killer whale recovery. Research projects have illuminated new aspects of killer whale biology, behavior, and ecology and helped us better understand the challenges this population faces. Targeted management actions, informed by research, have been taken to secure protections for the whales and their habitat, including:
- Designation of more than 2,500 square miles of critical habitat.
- Regulations to protect the whales from vessel impacts.
- Coordination with coastwide efforts to implement salmon recovery actions.
- Collaboration with partners on monitoring and minimization of harmful contaminants.
- Oil spill response plans to ensure we are prepared in the event of a spill.
Understanding the factors that affect the whales’ health will help us identify the most important threats, how they interact, and what we can do to reduce their impacts. New technologies are being developed to better understand risks of disease, assess individual body condition, and gain a better understanding of the health effects of carrying large contaminant burdens. We also plan to explore additional management actions outlined in the recovery plan to stabilize the population. In 2016, we completed a Species in the Spotlight 5-Year Plan of Action that builds on the recovery plan and details the focused efforts that are needed over the next five years.
Recovery of the Southern Residents and their preferred salmon prey, as well as protection of their broad and diverse habitat, is a long-term process that requires support over a large geographic area, from California to southeast Alaska. The continued success of research and conservation programs relies on leveraging resources and maximizing impact through partnerships. For example, the whales spend significant time in Canadian waters and are listed as endangered under the Canadian Species at Risk Act, so transboundary coordination has been, and will continue to be, important to recovery.
Our recovery criteria are built around a timeframe of 14 to 28 years based on the biology of these long-lived animals. It will take at least that long for us to evaluate the effectiveness of the protective measures put in place in the past several years. The past 14 years of federal funding and effort have secured a strong foundation of research and conservation, which we can build on to secure recovery of this iconic species for future generations.
Killer whales are protected under the Marine Mammal Protection Act. The AT1 Transient population is also considered depleted under the MMPA. Not all killer whales are listed under the Endangered Species Act. However, Southern Resident killer whales have been listed as endangered under the ESA since 2005. This means that the population of Southern Residents is in danger of extinction throughout all or a significant portion of its range.
We work to protect all populations of killer whales. However, our management work primarily focuses on recovery of the endangered Southern Resident population.
Recovery Planning and Implementation
Under the ESA, NOAA Fisheries develops and implements recovery plans for the conservation and survival of listed species. The ultimate goal of the Southern Resident killer whale plan is to recover the species, with an interim goal of down-listing its status from endangered to threatened.
The major actions recommended in the plan are:
- Support salmon restoration efforts in the region to ensure an adequate prey base.
- Reduce existing and monitor emerging contaminants.
- Reduce vessel impacts by improving whale watching guidelines and establishing regulations or protected areas as needed.
- Prevent oil spills and improve response preparation.
- Use available protections to minimize impacts from human-caused sound.
- Enhance public awareness and education.
- Improve responses to live and dead killer whales.
- Coordinate efforts with Canadian agencies, and with U.S. federal and state partners.
- Conduct research to facilitate conservation efforts.
The ESA authorizes NOAA Fisheries to appoint recovery teams to help develop and implement recovery plans. Rather than convening a recovery team for Southern Resident killer whales, we used an open public process to engage as many interested stakeholder groups and individuals as possible.
Critical Habitat Designation
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 2006, NOAA Fisheries designated inland waters of Washington State as critical habitat for the Southern Resident killer whale. We designated this habitat because it contains three features essential to the conservation of Southern Residents:
- Water quality to support growth and development.
- Enough prey to support individual growth, reproduction, and development, as well as overall population growth.
- Passage conditions to allow for migration, resting, and foraging.
In 2014, NOAA Fisheries started a process to revise the critical habitat of Southern Residents in response to a petition (PDF, 35 pages).
Supporting Salmon Restoration Efforts
Chinook salmon stocks are currently lower than historic levels, putting Southern Resident killer whales at risk for decreased reproductive rates and increased mortality rates. Some species of West Coast salmon are currently protected under the ESA and Magnuson-Stevens Fishery Conservation and Management Act. NOAA Fisheries coordinates habitat restoration efforts in Washington, Oregon, Idaho, and California to help restore salmon runs. Our scientists have also organized workshops and panels to better understand the effects of salmon fisheries on Southern Resident killer whales.
Killer whales are especially vulnerable to chemical contaminants because they are at the top of the food chain. To address this, NOAA joined the Puget Sound Partnership, a program that helps prevent contamination in Southern Resident habitat and collaborated with the U.S. Environmental Protection Agency and Washington State agencies to develop a plan to fill gaps in research and monitoring. NOAA's Damage Assessment, Remediation, and Restoration Program, which cleans up existing contamination, also has several active projects in the Pacific Northwest and California.
Preventing Oil Spills and Improving Response Preparation
Southern Resident killer whales are at risk of harm in the event of an oil spill. To reduce the risk of a spill, Washington’s Department of Ecology created the Spill Prevention, Preparedness, and Response Program. To minimize the effect of a potential spill on Southern Residents, NOAA developed the Marine Mammal Oil Spill Response Guidelines (PDF, 150 pages). Additionally, the Northwest Area Contingency Plan (PDF, 51 pages) includes methods to discourage killer whales from swimming into spilled oil.
Minimizing Impacts from Human-Caused Sound
Ocean noise threatens killer whale populations by interrupting their normal behavior. In 2011, NOAA Fisheries adopted regulations that prohibit vessels from approaching killer whales in inland waters of Washington State within 200 yards. We also encourage land-based whale watching as a way to enjoy viewing without any impacts.
Coordinating with Canadian Agencies, and U.S. Federal and State Partners
Because Southern Residents range from California to Alaska, recovery of their population requires cooperation across state and national borders. NOAA is coordinating with Fisheries and Oceans Canada, the Washington Department of Fish and Wildlife, the Center for Whale Research, and other partners to conduct research and implement recovery actions.
Developing Vessel Regulations and Minimizing Whale Watching Harassment
NOAA Fisheries supports responsible viewing of marine mammals in the wild and has adopted a guideline to observe all marine mammals from a safe distance of at least 100 yards by sea or land.
We have also taken steps to reduce threats to killer whales by regulating how close a vessel may get to the species in Washington State. This reduces disturbance to the animal and the potential for negative interaction. These regulations make it illegal to:
- Approach within 200 yards of a Southern Resident killer whale.
- Position a vessel to be in the path of a Southern Resident whale at any point located within 400 yards of the whale.
- Fail to disengage the transmission of a vessel that is within 200 yards of a Southern Resident killer whale.
- Feed a Southern Resident killer whale.
WhaleSENSE is a voluntary education and recognition program in the U.S. Atlantic and Alaska regions developed by NOAA Fisheries and partners in collaboration with the whale watching industry to recognize whale watching companies committed to responsible practices and minimizing whale watching harassment.
Companies participating in the WhaleSENSE program agree to:
- Stick to the regional whale watching guidelines.
- Educate naturalists, captains, and passengers to have “SENSE” while watching whales.
- Notify and report whales in distress.
- Set an example for other boaters.
- Encourage ocean stewardship.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings including large whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health. 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 identify strandings due 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.
All marine mammals, including killer whales, are protected in the United States under the MMPA. One population of killer whale—the Southern Resident—is listed as endangered under the ESA.
AT1 Transient Population
In 2002, National Wildlife Federation petitioned (PDF, 10 pages) NOAA Fisheries to designate the AT1 Transient pod as depleted after its drastic decline following the 1989 Exxon Valdez oil spill in Prince William Sound, Alaska. The spill was strongly correlated with the deaths of most of the AT1 Transient pod. There have been no observed births to the AT1 stock of the North Pacific transient killer whale population since 1984, and the population has steadily declined to 7 individuals.
In 2003, NOAA Fisheries reviewed a petition concerning the possibility that the AT1 killer whale group of Prince William Sound may be genetically distinct from other killer whales in Alaska, and may be depleted.
In 2004, NOAA Fisheries designated the AT1 stock as depleted under the MMPA.
Southern Resident Population
In 2015, we issued a 12-month finding on a petition to revise critical habitat for Southern Residents. Revisions are expected in 2017.
In December 2016, we completed a 5-year status review of Southern Resident killer whales.
Key Actions & Documents
- 12-month Finding on Petition to Revise Critical Habitat (80 FR 9682)
- 90-day Finding on Petition to Revise Critical Habitat (79 FR 22933)
- Final Rule 2006
- Final Rule - Amendment to include "Lolita" (80 FR 7380)
- FInal Listing Rule, 2005 (70 FR 69903)
- Proposed Rule - Amendment to include "Lolita" (78 FR 25044)
- 12-month Finding Not to Delist, 2013 (78 FR 47277)
- 90-day Finding - Amendment to include "Lolita" (78 FR 25044)
- 90-day Finding on Petition to Delist, 2012 (77 FR 70733)
NOAA Fisheries scientists are leading the effort to answer key questions about the risk factors potentially affecting killer whales, with a special focus on the Southern Resident population. Current research focuses on killer whales’ behavior, ecology, health, and human-caused impacts.
Our scientists and collaborators collected length and width data for killer whales using both vessel-based laser photogrammetry and aerial photography from an unmanned aerial systems (hexacopters). These metrics will be used to infer growth trends and current body condition, respectively, which will be related to trends in returning Chinook salmon—the whales’ primary prey. This research aims to provide a comparative assessment of nutritional status to guide management of these two protected populations.
Together with our partners, we track location data from satellite tags deployed on whales. This research helps determine the winter migration, feeding habits, and range of Southern Residents.
NOAA Fisheries' researchers and collaborators use digital acoustic recording tags, recording the sounds they receive and the sounds they produce, to examine sound exposure, sound use, and behavior of Southern Residents in their summer habitat. This research helps address threats like vessel disturbance, noise exposure, and effects on feeding.
Measuring Pollutant Transfer From Mothers to Offspring
Scientists study the transfer of pollutants from mother to offspring through blood during gestation and through milk during lactation. This research helps us understand whether young whales are at greater risk than adults for negative health effects from pollutants.
Measuring Energy Costs to Produce Sounds
Our scientists study the amount of energy dolphins need to produce loud sounds. Because dolphins and killer whales are related, research on dolphins is also applicable to killer whales. This research addresses the biological costs of environmental noise, as animals must produce louder sounds when human activities generate noise underwater.
Determining the size of killer whale populations helps resource managers determine the success of conservation measures and regulations. Our scientists collect population information on killer whales from various sources and present the data in annual stock assessment reports.
Southern Resident Killer Whale Monitoring & Research
Alaska Region Marine Mammal Stranding Network Newsletter
Alaska Region Marine Mammal Stranding Network Newsletter
Alaska Region Marine Mammal Stranding Network Newsletter