Marine Mammal Commission

North Atlantic Right Whale

The North Atlantic right whale is one the world’s most endangered species of large whale. North Atlantic right whales were first hunted as early as the 9th century by Norse whalers. Later, commercial whaling brought them to the brink of extinction by the early 1900s. The population off Europe had been virtually extirpated while a small population of perhaps a hundred or fewer survived in the western North Atlantic off the United States and Canada. After 1935, when an international agreement went into effect banning the hunting of all right whales, their numbers began to increase slowly. In recent decades, this slow recovery has been impeded by mortality and serious injury from ship strikes and entanglement in fishing gear. North Atlantic right whales now occur almost exclusively along the east coasts of the United States and Canada, where they rely on a calanoid copepod, Calanus finmarchicus as their primary food source.

The North Atlantic right whale is one of three right whale species, along with the North Pacific right whale and the southern right whale. Today, there are likely fewer than 500 right whales in the entire North Pacific, and approximately 30 individuals in the eastern North Pacific stock inhabiting U.S. waters, while southern right whale populations have seen steady increases since the end of commercial whaling in the southern hemisphere.

Right whale off Florida coast

Right whales off Florida coast. (New England Aquarium)

Species Status

Abundance and Trends

During the 1990s, the right whale population fluctuated between periods of slow decline and periods of slow growth. In the first decade of the 2000s, it grew steadily but at a rate well below those of many other populations of large whales. In 2010, the population entered a period of decline that appears to be continuing due to high levels of human-caused mortality and declining calf production. Human-caused mortality and serious injury, particularly entanglements and vessel strikes, is the greatest threat to recovery of the species. Today, there are an estimated 350-400 North Atlantic right whales in existence, with fewer than 95 reproductive-age females in the population. Female numbers are declining more rapidly than males, and the corresponding loss of reproductive potential leads to an alarming concern about an increasing risk of extinction.

In late October 2020, NMFS reported a preliminary population abundance estimate of 366 North Atlantic right whales alive in January 2019 and a revision of its original January 2018 estimate down from 412 to 383 right whales for that year.  These estimates are considered preliminary pending further analysis and a robust internal and external peer-review process, including review by the Atlantic Scientific Review Group, and a public comment period on the draft 2021 Stock Assessment Report.


Although North Atlantic right whales now occur almost exclusively along the east coasts of the United States and Canada, a few individuals have been observed entering the Gulf of Mexico and venturing across the Atlantic to European waters. Their current range is closely linked to their life history, contingent upon nursery areas and feeding grounds with the right characteristics. Many North Atlantic right whales travel from their feeding grounds off the coast of the northeastern United States and Canada down to coastal waters of South Carolina, Georgia, and Florida in winter, while a portion of the population remains in more northern waters in areas such as south of Nantucket and around Cape Cod. The warm, shallow waters off the southeast U.S. coast serve as winter nursery grounds for the whales. The North Atlantic right whales then migrate north again along the east coast to their feeding areas, many arriving in Cape Cod Bay in early spring and then moving into productive waters of the Gulf of Maine and in more recent years, the Gulf of St. Lawrence. The North Atlantic right whale distribution seems to be shifting, yet questions remain about the permanency of the shift and the location of significant portions of the population at any given time.

Unusual Mortality Event: 2017 to Present


Right Whale Mortality Since 1970

Right whale mortalities from collisions with ships, entanglement in fishing gear, perinatal (new born calf) deaths, and unknown causes (NMFS). Note that individual whales that were seriously injured (by vessel strike or entangled in gear) and not resighted are included.

Since June 2017, 31 individual North Atlantic right whale confirmed deaths, or mortalities, have been observed (21 in Canada; 10 in the U.S.). The elevated mortality level in 2017 led NMFS to declare an Unusual Mortality Event (UME) for North Atlantic right whales, which remains an open investigation. In addition to the 31 deaths under this UME, twelve right whales have been determined by NMFS to be seriously injured, i.e., injured severely enough to most-likely die from that injury.  At least seventeen of the 43 individuals confirmed dead or seriously injured under this UME have been female, representing a serious loss to potential calf production. Vessel strikes and entanglements in rope were the predominant cause of death for those that could be examined, however some of the whales that died could not be examined or were too decomposed to determine the cause of death.

While North Atlantic right whale deaths have been detected historically in U.S. waters, reflective of their distribution along the Atlantic coast of the U.S., the majority of the carcasses reported in 2017  and 2019  were concentrated in Canadian waters. The increasing presence of North Atlantic right whales in the Gulf of St. Lawrence in Canada is believed to reflect a northward shift in their prey, hypothesized to result from particularly strong climate-driven conditions, including ocean warming, in the waters of the northwestern Atlantic Ocean. This change in North Atlantic right whale distribution has led to an increase management and implementation of protective measures to reduce vessel strikes and entanglement in fishing gear in the Gulf of St. Lawrence.

What the Commission Is Doing

Stakeholder Engagement and Managing Impacts of Fishing

To reduce threats due to fishery interactions to the North Atlantic right whale population and other large whales in the Atlantic, in 1996 we recommended that NMFS establish a take reduction team in 1996, which led to the establishment of the Atlantic Large Whale Take Reduction Team (ALWTRT) and the developed of a Take Reduction Plan (TRP) in 1997. A representative of the Commission has been a member of the team since its inception. More recently, the Commission expressed concern to NMFS regarding the 2017-19 spike in human-caused serious injuries and deaths of North Atlantic right whales, the population’s low birthing rate and declining population size, and the need for immediate, strong measures to mitigate human-based threats to the species. In September of 2019, the Commission submitted a letter to NMFS on the intent to prepare a draft environmental impact statement and to amend the current Atlantic Large Whale Take Reduction Plan iterating these concerns and offering specific recommendations for management actions.

In addition to engaging on the ALWTRT, the Commission has awarded research grants aimed at right whale conservation. For example, the Commission provided funding to evaluate the potential use of ropeless fishing systems in lobster pot fisheries back in 2016.

At its Annual Meeting on 5-7 April 2017 in North Falmouth, MA, the Commission devoted a session to receiving and reviewing recent information on the status of North Atlantic right whales. Among other things, it was noted that annual calf production in recent years has fallen to its lowest rate in 38 years and that the frequency and severity of entanglement-related wounds has been increasing significantly. Based on the information presented and discussed at the meeting, the Commission concluded that entanglement in fishing gear was the single greatest human-caused threat to North Atlantic right whales, and that measures to reduce the lethal and sub-lethal effects of entanglement in both the United States and Canada were inadequate. On April 19, 2017, the Commission wrote to the NMFS offering preliminary comments based on meeting findings and urged the agency to take immediate steps to strengthen measures to reduce entanglement.

Efforts to Reduce Impacts of Ship Strikes

The Marine Mammal Commission is continuing to monitor right whale deaths and injuries caused by ship strikes in U.S. waters, and making efforts to minimize their occurrence. Aside from an assumed vessel strike in 2017, the vessel speed zones that were established in 2008 by the National Marine Fisheries Service (NMFS) to reduce collisions with right whales by large vessels have been largely effective. In March 2014, the Commission recommended denial of a petition by the American Pilots Association requesting that dredged channels be exempted from speed restrictions in management areas. In 2014, we met with NMFS staff to review the status of the petition and also reviewed its status at our Annual Meeting in May 2015. NMFS denied the petition in October of 2015.

Commission Reports and Publications

Laist, David W., Knowlton, Amy R., and Pendleton, Daniel. 2014. Effectiveness of mandatory vessel speed limits for protecting North Atlantic right whales.

Laist, David W., Knowlton, Amy R., Mead, James G., Collet, Anne S., and Podesta, Michela. 2001. Collisions Between Ships and Whales.

Reports prepared for the Marine Mammal Commission:

Lowry, Lloyd, Laist, David W., and Taylor, Elizabeth. 2007. Collisions Between Ships and Whales.

Weber, Michael L. and Laist, David W. 2007. The Status of Protection Programs for Endangered, Threatened, and Depleted Marine Mammals in U.S. Waters.

Reeves, Randall R., Read, Andrew J., Lowry, Lloyd, Katona, Steven K., and Boness, Daryl J. 2007. Report of the North Atlantic Right Whale Program Review.

Commission Letters

Letter Date Letter Description
September 23, 2019

Letter to NMFS on the notice of intent to prepare a draft environmental impact statement and to amend the Atlantic Large Whale Take Reduction Plan.

August 12, 2019

Letter to NMFS conveying Commission’s concerns regarding the 2017-19 spike in human-caused serious injuries and deaths of North Atlantic right whales, the population’s low birthing rate and declining population size, and the need for immediate, strong measures to mitigate human-based threats to the species

June 19, 2017

Letter to NMFS on the role of entanglement in reducing North Atlantic right whale abundance and management actions to monitor and reduce fishery-related interactions

April 19, 2017

Follow-up letter to NMFS from the Marine Mammal Commission’s 2017 Annual Meeting on North Atlantic right whales

April 13, 2016

Letter to U.S. Coast Guard on Atlantic Coast Port Access Route Study Final Report

April 21, 2015

Letter to NMFS on proposed modification of critical habitat for North Atlantic right whales

April 20, 2015

Letter to NMFS on proposed exemption of various state waters from the Atlantic Large Whale Take Reduction Plan and establishment of new gear marking requirements

November 21, 2014

Letter to NMFS on proposal to delay the start date for the Massachusetts Restricted Area under the Atlantic Large Whale Take Reduction Plan

March 4, 2014

Letter to NMFS on a petition to exempt dredged channels from vessel speed restrictions

September 13, 2013

Letter to NMFS on proposed rule to reduce right whale entanglement in commercial trap/pot and gillnet fishing gear

August 5, 2013

Letter to NMFS on proposed rule to delete the expiration date for regulations limiting vessel speeds

April 20, 2012

Letter to NMFS on report evaluating the effectiveness of the final rule to implement vessel speed restrictions to reduce the threat of vessel collisions

Learn More


The primary causes of mortality and injury to right whales are entanglement in fishing gear and strikes by vessels. Another potential threat include spills of hazardous substances from ships or other sources. Lastly, noise from ships and industrial activities within their range is a great concern for the whales, and the Commission provides comments on proposed activities and recommendations on how to avoid or mitigate such threats.

Current Conservation Efforts

recovery plan for the species was adopted in 1991 and updated in 2005. In 1994, three areas were designated as critical habitat. In January 2016 those areas were expanded and consolidated into two large areas, one covering waters off the northeastern United States in the Gulf of Maine from the U.S.-Canada border to eastern Massachusetts, and the other area along the southeast coast from southern North Carolina to central Florida (see NOAA National Marine Fisheries Service (NMFS) website for critical habitat maps).

NMFS and the Coast Guard have taken both regulatory and non-regulatory steps to reduce the threat of ship strikes, including mandatory vessel speed restrictions in Seasonal Management Areas, modification of international shipping lanes, enforcement, and public outreach.

To address entanglement in fishing gear, NMFS established the Atlantic Large Whale Take Reduction Team. This team has been unable to agree on all measures needed to meet take reduction goals and the NMFS has therefore developed a plan it believes will be necessary to reduce the incidental serious injury and mortality of right whales, as well as other whales. NMFS is in the process of considering additional mitigation measures in response to the impact of Northeast fisheries on North Atlantic right whales.

Additional Resources

NMFS Marine Mammal Stock Assessment Reports by Species/Stock – Right Whale, North Atlantic

NMFS 2005 Recovery Plan for the North Atlantic Right Whale

North Atlantic Right Whale Recovery Plan Northeast U.S. Implementation Team 

North Atlantic Right Whale Recovery Plan Southeast U.S. Implementation Team 

NOAA Interactive Map of North Atlantic Right Whale Sightings

Canada – WhaleMap: Latest Right Whale Observations

NMFS – Reducing Vessel Strikes to North Atlantic Right Whales

NMFS – North Atlantic Right Whale

North Atlantic Right Whale Consortium