Deep dive...into Right whales

A type of baleen whale, right whales have three different species – the North Atlantic right whale (Eubalaena glacialis), the North Pacific right whale (Eubalaena japonica) and the Southern right whale (Eubalaena australis).  

While the three species differ genetically and are found in different parts of the world, they don’t differ significantly in their appearance. Weighing in at up to 100 tonnes, right whales are typically 13 to 17 metres long. Females are usually slightly larger than males.  

Right whales have stocky black bodies with no dorsal fins and their tails are broad and all black. When it comes to their bellies, they’re either all black or have irregular white patches. The species also has arching rostrums and relatively short paddle-like pectoral fins.  

A distinctive feature of right whales is the patches of rough thick skin that appear on their heads. Called callosities, these have a white appearance as it’s actually whale lice that is covering up otherwise black skin. Callosities help researchers to photo identify individual whales and to track them over the years, helping to increase our knowledge of right whale populations and their behaviours.  

From a distance, the tall V-shaped blow of right whales could easily be mistaken for that of a humpback whale but up close, their appearance (particularly the callosities) distinguishes the right whale from their fellow baleen whale.  

It’s long been said that the right whale’s name comes from the time when whalers considered them the ‘right’ whale to hunt as they were easy to catch (moving slowly and staying close to the coast) and yielded large amounts of oil and blubber.

However, as pointed out in Leviathan: The History of Whaling in America, some people who have studied the issue have pointed out that the word ‘right’ in this context might just have meant ‘true’ or ‘proper’, as in ‘typical of the group’.  

When it comes to life span, scientists believe that right whales can live to at least 70 years of age. Scientific monitoring of the species is relatively recent, though, so more research needs to be done.   

Right whales migrate every season between summer feeding grounds and winter breeding grounds (where they calve and mate).  

The North Atlantic right whale is found along the eastern coast of the U.S. (particularly off New England) and Canada, and their summer feeding grounds extend north to the Scotian shelf and the Bay of Fundy. They head to the warmer waters off Georgia, North and South Carolina and Florida in the winter.  

Southern right whales are found in the southern hemisphere – feeding in the sub-polar waters around Antarctica and migrating to the southern costs of South America, Southern Africa, New Zealand and Australia.  

Little is known about the migratory patterns of the North Pacific right whale but they follow the general pattern of spending summer in far north feeding grounds and heading south to warmer waters (like those off southern California) during the winter.  

There are two populations of the North Pacific right whale – a western population found off the coasts of Russia and Japan and an eastern population found mostly in the eastern Bering Sea. A few individuals have also been sighted in the northern Gulf of Alaska, south of Kodiak Island.  

The eastern population is thought to number no more than 50 whales, making it one of the smallest known populations of whales in the world.

Common right whale behaviours include breaching, swimming with their rostrum out of the water as they skim feed on plankton, and socialising at the water’s surface.  

Like other types of whales, right whales use song to communicate – mostly using low frequency moans, groans and pulses.  

Right whales were hunted to the brink of extinction during the centuries of commercial whaling and North Atlantic and North Pacific right whale populations have never recovered from this massive depletion.  

The critically endangered North Atlantic right whale is at its lowest point population-wise in 20 years. The latest estimate suggests there are less than 350 individuals remaining in the world. 

The North Pacific right whale is listed as endangered on the IUCN Red List. Data is limited for the species but estimates suggest 300-400 whales in the western population and up to 50 in the eastern population.  

Most Southern right whale populations are, encouragingly, now on the increase. They are designated Least Concern on the IUCN Red List. Estimates put the population at 10,000 to 15,000.

Like other baleen whales, right whales strain large volumes of ocean water through their baleen plates, filtering out their food. They mainly eat copepods (tiny crustaceans), plankton and krill.  

They pick up their food throughout the ocean – heading to the seafloor, eating in the middle levels and also foraging at the surface. Right whales also feed by keeping their mouths open as they move through the water (called skimming).  

Like other whales, right whales can become entangled in fishing gear which goes on to cause injury, fatigue, comprised feeding and sometimes even death. 

NOAA Fisheries and its partners estimate that over 85 per cent of right whales have been entangled in fishing gear at least once. Even if the whale can be disentangled from fishing gear, the time already spent entangled can severely stress the whale, prevent it from feeding and exhaust it.  

Scientists believe that chronic entanglements are one reason why female right whales are having fewer offspring and are taking longer to have them.  

This is a particular risk for North Atlantic right whales, whose habitat and migration routes are close to major ports along the Atlantic coastline and who cross over with busy shipping lanes. Collisions can severely injure or kill whales.  

As Arctic sea ice continues to decrease and ship traffic increases in the region, it’s thought that the North Pacific right whale will become increasingly vulnerable to vessel strikes.  

Climate change and pollution are a threat to all whales and dolphins because of the loss of habitat as waters become warmer and resulting pressures on food sources. 

Harmful algal blooms have been documented in North Atlantic and Southern right whales, and been identified as a threat to both populations. There’s also concern that algal toxins may be emerging as a threat to North Pacific right whales. 

Plastics and micro plastics, along with chemical pollutants, entering into the water system are a serious threat to all creatures in our ocean.

Right whales, like other whales, use noise to communicate and to locate prey and increased noise pollution from vessels and other human activity interferes with this ability. 

Take a look at this video from CBS Boston (April 2023) about rescue efforts for a right whale entangled in fishing gear: