Right whales in the North Atlantic are SHRINKING. Today’s animals are up to 3ft shorter than those born 30 years ago, and scientists believe fishing is to blame.

According to new research, North Atlantic whales born were close to a metre (3ft 3 inches) smaller than those born in three decades, so fishing would severely threaten their survival. It may be to blame.

These are one of the most threatened whale species on the earth, and although being generally protected from hunting, their populations have declined significantly.

It is estimated that there were over 5,000 North Atlantic right whales in the globe in the early twentieth century, which had fallen to 100 by 1980 and has since risen to approximately 365.

The scientists from the National Oceanic and Atmospheric Administration (NOAA) in California, investigated their body length using aerial photogrammetry data obtained from aeroplanes and remotely controlled drones over 20 years.

According to experts participating in the study, North Atlantic right whales have shrunk by around a metre since aerial surveillance began in the 1980s.

The team believes that entanglement in fishing gear, changes in prey distribution, and other human activities have resulted in shorter whales due to stress on the mother and food shortages.

WHAT ARE THE NORTH ATLANTIC RIGHT WHALES?

• North Atlantic right whales are a kind of marine mammal that may grow to be 60 feet long (20 metres).
• They may weigh up to 70 tons (64 tonnes) and consume around 5,500 pounds (2,500 kg) daily.
• They often calve in the Atlantic Ocean off the coasts of Georgia and Florida before moving farther north.
• In recent years, premature deaths due to being entangled in fishing lines and unfortunate collisions with ships have reduced the population.
• Phytoplankton is an important food source for whales.
• This phytoplankton has suffered recently as the Gulf of Maine’s water temperature has risen due to global warming.
• Before travelling farther north, they frequently calve in the Atlantic Ocean off the shores of Georgia and Florida.
• In recent years, premature fatalities due to becoming entangled in fishing lines and unfortunate encounters with ships have diminished the population.
• Whales rely heavily on phytoplankton for nourishment.
• This phytoplankton has lately suffered as the water temperature in the Gulf of Maine has increased owing to global warming.

The latest study, published in the journal Current Biology, reveals that, in addition to decreased population levels, those whales who survive are in trouble.

Compared to whales born in the 1980s and 1990s, up to 40 years ago, they discovered a considerable decline in length.

Dr Joshua Stewart of the National Oceanic and Atmospheric Administration (NOAA) in La Jolla, California, is among the scientists. Who led the study stated that the 7% reduction is only an average and that in certain extreme circumstances, baby whales are several metres shorter than predicted.

‘Major effects on life history like this have been described in severely exploited commercial species, particularly fishes, but this is the first time these implications have been observed in a big mammal, to our knowledge.’

Dr Stewart and his colleagues aimed to describe the difficulties that suitable whales confront as evidenced by changes in their life cycle traits, such as size.

They turned to the skies, scrutinizing photographs acquired by drones and aeroplanes over the previous 20 years for variations in body length.

These whales may grow more than 14 meters (45 feet) long, although those born recently have been closer to 10 meters (32ft).

Dr John Durban of Oregon State University, who was also participating in the project, said they were able to build on work done in the early 2000s using conventional planes to monitor whales.

They have recently incorporated drone technology, which allows them to increase observation durations and areas.

‘In both situations, they were able to determine whales via launching a camera close above them,’ said the scientists. Effectively giving them a health check without their realizing we were there,’ says the researcher.

The whales were an ‘excellent’ case study for the researchers since they had been observed continuously since the 1980s, containing individual information on age, size, and weight through records of attached-gear entanglements.

According to experts participating in the study, North Atlantic right whales have shrunk by around a metre since aerial surveillance began in the 1980s.

Intensive monitoring over decades enabled the NAOO team to assess the consequences of severe and sustained entanglements with fishing vessels and nets.

They sought to know how these interactions would affect people’s long-term fitness and the consequences of other stressors, including vessel noise, ship hits, and altering prey availability.

‘Fishing gear entanglements in this species are regrettably rather prevalent, and entanglements resulting in connected gear and serious injuries have typically been rising over the past several decades,’ Dr Stewart added.

‘Previous research has demonstrated that the higher drag from entangling gear compels right whales to expend a significant amount of extra energy merely to go about their routine activities, the energy that could otherwise be spent on development or reproduction.’

Intensive monitoring over decades enabled the NAOO team to assess the consequences of severe and sustained entanglements with fishing vessels and nets.

‘Entanglements can be deadly in some situations, but it turns out that even sub-lethal entanglements can have long-term effects on right whales,’ said Dr Stewart.

They discovered that entangled fishing gear is one of the stresses on whales associated with them growing shorter bodies.

Dr Stewart hypothesized that stunted development might contribute to decreased reproductive success and an increased risk of life-threatening gear entanglement.

He also feels that the discoveries in right whales may have repercussions for other big whale species throughout the planet.

‘The smaller you are, the fewer energy reserves you have, and the more difficult it may be to endure a significant entanglement or prolonged food scarcity,’ he noted.

They discovered that entangled fishing gear is one of the stresses on whales associated with them growing shorter bodies.

‘As a result, these life history alterations may influence population viability.’ But it makes me question how many giant whales are affected by entanglements worldwide,’ added Dr Stewart.

‘This is not an issue limited to right whales; entanglements are a huge hazard to whales, marine animals, and other marine species worldwide.’

‘Because North Atlantic right whales have such a comprehensive dataset with known ages, sizes, entanglement histories, and so on, we were able to directly analyze how these factors impact growth rates.

‘My opinion is that many other species are equally affected, but we can’t identify it in less well-studied populations,’ says the researcher.
Based on their findings, the researchers advocated for more aggressive action to lessen the environmental effect of fishing gear and vessel operations.

According to study co-author Amy Knowlton of the New England Aquarium, it is critical to employ proven remedies such as slowing vessels down, reducing breaking strength, and ropeless fishing gear in the vicinity of these whales.

She stated that implementing these activities is “essential and urgent” to “avert the extinction of this species.”

The researchers will now investigate if shorter female whales have fewer progeny.