- Scientific name: Eubalaena glacialis
- Species of Greatest Conservation Need (MA State Wildlife Action Plan)
- Endangered (MA Endangered Species Act)
- Endangered (US Endangered Species Act)
Description
The North Atlantic right whale reaches about 14 m (45 feet) in length and weighs 45 to 54 metric tons (50 to 60 tons), but larger animals were reported historically. This rotund baleen whale has a stocky black body, lacks a dorsal fin, and has a narrow and strongly arched rostrum. The mouth is lined with about 250 very long (up to 2 m [7 feet]) black baleen plates fringed with fine hairs on each side. The species has callosities (raised patches of rough skin) on the rostrum, chin, above the eyes, and behind the blowhole. Most individuals have white patches on their abdominal area, but the majority of the whale is black to dark gray. The head is relatively large, taking up about a quarter of the length of the body. Only the sperm whale has a relatively larger head, taking up about a third of the length of the body.Identification in the field is assisted by a characteristic V-shaped blow.
Life cycle and behavior
North Atlantic right whales live to at least 50 years of age. The closely related bowhead whale in the North Pacific may live over 100 years. Females give birth to their first calf at 10 years of age, with the gestation period lasting approximately 12 months. A calf can be up to 4.2 meters (14 feet) long at birth. North Atlantic right whales are occasionally observed from the beaches of Cape Cod, especially near Race Point, in the spring, where they feed on zooplankton, including copepods, euphausiids, and cyprids. North Atlantic right whales sometimes feed by skimming prey from the surface of the water as they swim through a patch of plankton with their mouth open. They then use their tongue to force the water through their baleen, the comb-like fibrous plates hanging from the upper jaw while retaining the zooplankton in their mouth.
Amphipods called whale lice heavily infest the callosities of the North Atlantic right whale, sometimes giving their heads a yellowish-white patchy appearance. Whale lice are often called external parasites, but they are really symbionts, feeding on sloughed whale skin and damaged tissue. Although there is no definitive evidence of killer whale predation on North Atlantic right whales in the North Atlantic, about 5% of the population exhibit parallel raking scars on their tail flukes, which match the dentition of the killer whale.
Shifts in phenology: North Atlantic right whales appear to be leaving Massachusetts Bay to feed in Cape Cod Bay 40 days earlier each late-winter / early spring between 2008 – 2011, though results are variable (the trend reversed the last two years of the study), which may be due to warming conditions in the northwestern Atlantic Ocean (Charif et al., 2020). Moreover, another study found a similar pattern; earlier spring transition dates have driven earlier movements between habitats from 1998 - 2017, indicating that North Atlantic right whales may respond to temperature to start migration to Cape Cod Bay (Ganley et al., 2022). Peak habitat use of North Atlantic right whales in Cape Cod Bay shifted 18.1 days earlier from 1998 – 2018 and was negatively related to the earlier onset of spring in the Gulf of Maine (Pendelton et al., 2022). North Atlantic right whales are also staying longer in Cape Cod Bay later in the spring season, albeit with high interannual variability (Pendeltton et al., 2022).
Shifts in annual and seasonal migration patterns of North Atlantic right whales have been linked to changes in the distribution and availability of their primary copepod prey, Calanus finmarchicus (Pershing et al. 2021). Further, recent population changes and decreased calving rates have been linked to the higher energetic costs associated with longer search times for optional foraging grounds and lower quality food resources associated with warming waters in the region (Staudinger et al., 2020; Pershing et al., 2021; Pendelton et al., 2022).
Population status
The North Atlantic right whale is listed as endangered under both the federal and state endangered species acts. From the early 1500s to the 1920s, these whales were extensively hunted in the western North Atlantic. A full prohibition on hunting began in 1935. It is believed that the western North Atlantic right whale population now only includes about 372 individuals, with fewer than 70 reproductively active females. The eastern North Atlantic right whale population is nearly extinct, with numbers estimated in the low tens. Currently, ship collisions and entanglement in fishing gear are the two most important causes of mortality. Numerous fishing gear regulations and ship speed and routing guidelines have not yet successfully reduced mortality to a sustainable level for recovery. The North Atlantic right whale is in greater jeopardy of extinction than any other vertebrate animal found in Massachusetts.
Distribution and abundance
North Atlantic right whales are confined (endemic) to the North Atlantic Ocean. They usually occur from the Gulf of St. Lawrence south to northern Florida, but individual whales may disperse beyond these limits. Different parts of their range are used for different purposes, including distinct feeding areas, calving areas, nursery aggregation areas, and breeding locations. Historically, healthy populations of the North Atlantic right whale occurred on both sides of the North Atlantic. They primarily inhabit coastal and shelf waters, moving to higher latitudes during the spring and summer. In the western North Atlantic, aggregations of right whales are found seasonally in 5 high use areas, including (1) the Gulf of St. Lawrence, (2) Roseway Basin south of Nova Scotia, including Browns and Baccaro Banks on the Scotian Shelf, (3) Massachusetts Bay and eastern Cape Cod Bay, (4) south of Martha’s Vineyard and Nantucket, the Great South Channel between Nantucket Island and Georges Bank, including the northern edge of Georges Bank, and (5) off the coast of the southeastern United States from Cape Fear, N.C., to St. Augustine, Fl.
Shifts in range, elevation, or depth: From 2004–2014, North Atlantic right whales appeared less prevalent in the Gulf of Maine but more common in the Mid-Atlantic and Southern New England, though the study did not evaluate the causation of the shift (Davis et al., 2017; O’Brien et al., 2022). Models using climate change projections (specifically RCP 4.5 and 8.5) show that much of the Gulf of Maine will be unsuitable habitat for North Atlantic right whales in late summer and fall, except for some areas along the Scotian Shelf (Ross et al., 2021).
Habitat
North Atlantic right whales concentrate in Cape Cod Bay and the Great South Channel east of Nantucket Island in small numbers from December to March, and in larger numbers in April and May. These areas are important feeding grounds for the species because of the unusually dense concentrations of zooplankton. Few North Atlantic right whales remain in Massachusetts waters throughout the summer; the majority of the population spends summer and fall in the Gulf of St. Lawrence, Bay of Fundy and on the Nova Scotian shelf. Right whales move south to warmer waters off the coast of Georgia and Florida to calve.
Healthy habitats are vital for supporting native wildlife and plants. Explore habitats and learn about conservation and restoration in Massachusetts.
Threats
Marine mammals, particularly the large migratory whales and porpoises in the Northeast, are experiencing high rates of ocean warming, acidification, and other climate impacts to affect their distribution, phenology, and population dynamics (Letrick et al., 2023). Relatively few studies of marine mammal responses to climate change exist in part due to the difficulties in detecting and tracking their populations over the broad spatial scales that constitute their geographic ranges. Several of the large migratory whales have shown shifts in range and phenology over recent decades; however, the rate, magnitude, and direction of these shifts vary widely across sub-regions of their range and studies (Ramp et al., 2015; Charif et al., 2020; Pendleton et al., 2022). These conflicting patterns of earlier or later arrival may be due to the different methods used to monitor populations (e.g., acoustics vs aerial visual observations) with different detection abilities and spatial coverages.
Shifts in the distribution of marine mammals are largely attributed to the indirect effects of climate change, as prey availability, abundance, and quality are altered due to ocean warming and acidification. Planktivorous species like North Atlantic right whales, which depend on seasonally reliable concentrations of highly nutritious and lipid-rich calanoid copepods, are more sensitive to bottom-up changes in primary and secondary production compared to piscivorous whales (Pendleton et al., 2022). However, rapid warming in the Gulf of Maine is having broad impacts on regional food webs with ramifications not only for whales but many other marine fish and seabirds that consume zooplankton or planktivorous forage fish such as sand lance and herring (Staudinger et al., 2019; Pershing et al., 2021). Most notably, increasing SSTs are negatively affecting cold-adapted subpolar copepod species, including Calanus finmarchicus through decreased growth, productivity, and shifts in overwintering phenology schedules (Staudinger et al., 2019; Staudinger et al., 2020; Pershing et al., 2021).
As food resources become increasingly unpredictable, migratory whales are occurring in unexpected locations and at unexpected times or showing elevated mortality and stranding rates, as indicated by the declaration of “Unusual Mortality Events” in the region (NOAA, 2024)1. This increases the potential for conflict and the incidence of injury and mortality of these already at-risk and endangered species with human activities such as shipping, fishing, and wind energy development.
Conservation
Consistent and expanded distribution monitoring of whale and porpoise populations is needed to better track populations over time and space and predict occurrence, especially as wind energy development areas are pursued and a better understanding of the distribution and occurrence of key prey populations and their responses to climate change. The region's most important and least understood populations that are shared prey across whales and other RSGCN include calanus copepods, C. finmarchicus in particular, and forage fishes, including sand lance, Atlantic herring, and river herring species. Studies on the physiological responses and energetic demands associated with climate-induced shifts in distribution, phenology, and foraging behaviors in marine mammals will help fill key knowledge gaps and increase understanding of changes in population changes due to altered growth and survival rates. Model projections of climate-induced distribution and phenology changes paired with current and future fishing areas, shipping corridors, and wind energy development areas can aid marine mammal conservation efforts by identifying intersecting spatiotemporal risk areas under different closure and operation schedules scenarios.
Stranded Whales
For all live or dead marine mammal strandings, please call one of the following hot lines:
For Cape Cod: 508-743-9548 (IFAW Marine Mammal Rescue and Research)
For all other areas: 866-755-NOAA (Northeast Marine Mammal and Sea Turtle Stranding and Entanglement Hotline)
Be prepared to provide the following information:
- Name and contact number
- Location of animal with detailed description and nearby landmarks, if possible
- Number, size, and type of animal
- Any other helpful information such as behavior or tidal cycle
- If the carcass is marked with grease pen or tagged, note the tag’s color, number, and position on the animal
- Keep a safe distance away from the animal.
References
North Atlantic Right Whales (Eubalaena glacialis). Office of Protected Resources, NOAA Fisheries. URL: https://www.fisheries.noaa.gov/species/north-atlantic-right-whale
National Marine Fisheries Service. 2005. Recovery Plan for the North Atlantic Right Whale (Eubalaena glacialis). National Marine Fisheries Service, Silver Spring, MD. 137 pp. file:///C:/Users/Owner/Downloads/noaa_3411_DS1 (2).pdf
National Marine Fisheries Service. 2022. North Atlantic Right Whale (Eubalaena glacialis) 5-year Review: Summary and Evaluation. National Marine Fisheries Service, Silver Spring, MD. 55 pp. https://www.fisheries.noaa.gov/s3//2022-12/Sign2_NARW20225YearReview_508-GARFO.pdf
Contact
| Date published: | March 14, 2025 |
|---|