Blue whale
Common Name: Blue whale
Scientific Name: Balenoptera musculus
OSPAR Regions where it occurs: I, II, III, IV, V
OSPAR Regions where under threat and /or in decline: I, II, III, IV, V
Description: The blue whale is the largest animal known to have existed on Earth. Blue whales in the Northern Hemisphere are somewhat smaller than their counterparts in the Antarctic. The largest animal recorded for the Northern Hemisphere was a 28.1 m long female reported in whaling statistics. Blue whale females are about 1.5 m longer than males (Calambokidis et al., 1997). Body weights of adults generally range from 80 to 150 tons.
What is the latest status ?
The status assessment describes the latest changes in distribution, abundance and range of the feature, as well as any changes in the threats and pressures impacting the feature. The status assessments are updated regularly and inform OSPAR’s consideration of the effectiveness of the measures and actions that have been adopted and implemented by Contracting Parties.
Why is this feature included on the OSPAR List? |  | |
What protective measures and actions has OSPAR committed to taking? |  |  |
What actions have been implemented by OSPAR? | An implementation report will be published in July 2022 | |
Key message
Blue whales regularly occur in Regions I (Barents Sea, Svalbard) and V (Iceland, Azores), and recently in Region III (Ireland). Rare sightings are known from region IV (Spain, France).
Populations were seriously reduced in the 19th and 20th century due to industrial whaling (e.g. >10,730 whales killed in the North Atlantic between 1868-1965).
Hunting stopped officially with the whaling moratorium on blue whales in 1966 though the last deliberate kill was in 1978 (Cooke 2018).
The current abundance for the NE Atlantic is unknown, and while they are still considered to be rare, there are indications that the population off Western and Northern Iceland is increasing (2015: 3,000 individuals).
The global assessment of IUCN for the Blue Whale categorize the status as endangered (Cooke 2018).
For more information please read our latest assessment
Threats and Impacts
Whaling: In the past, whaling was the main threat to the species. Currently blue whales are protected and not subject to hunting. However, fin whales are hunted by Iceland and there have been a number of incidents where blue-fin whale hybrids have been taken (MFRI 2018). Due in part to the low density of the species, it is difficult to assess the scale of potential impacts though the following are likely threats:
Ocean noise: Human activities such as naval sonars, seismic exploration or ship traffic (including whale watching) produce sounds that can have a negative impact on this species, for example by disrupting feeding activities (Sears & Perrin 2018, Southall et al. 2019, Di Iorio & Clark 2010).
Ship strikes: Blue whales are subject to collisions with ships, causing injury or death. While in the North Atlantic, records of blue whale ship strikes are very rare the expected increase in shipping activity in the Arctic region in the near future makes it likely that ship strike incidents will occur more often.
Entanglements: While no entanglements have been reported for the OSPAR area, it is a potential threat that has not yet been quantified.
Pollution: As long-lived cetaceans, blue whales are likely to be negatively impacted by pollutants in the marine ecosystem though their low trophic feeding affords them some protection.
Climate change: Potential climate change impacts on the marine ecosystem are still poorly understood. Changes in ocean acidity, water temperature and currents could lead to a reduction in prey.
For more information please read our latest assessment
Measures that address key pressures from human activities or conserve the species/habitat
Other relevant competent authorities are IWC and NAMMCO and IMO.
NAMMCO provides management advice to the Faroe Islands, Greenland, Iceland and Norway on the conservation status of blue whales. Blue whales are protected by all NAMMCO member countries.
Blue whales have been protected worldwide since 1966, and no deliberate catch of blue whales has been recorded since 1978 (Cooke 2018).
Actions of OSPAR related to climate change and pollution might benefit the species.
The overview assessment of implementation reporting was not available at the time of publishing this status assessment. Future updates of the status assessment will take implementation reporting against OSPAR actions into account.
For more information please read our latest assessment
