Gray whales shrinking in size along the Pacific Northwest coast

A concerning trend has emerged among gray whales that frequent the Pacific Northwest coast - they have been shrinking in size over the past 20-30 years.

A new study led by researchers at Oregon State University has found that gray whales in this region have decreased in body length by an average of 13 per cent since around the year 2000.

The study focused on a subgroup of around 200 gray whales known as the Pacific Coast Feeding Group (PCFG), which spends its summers feeding in the warmer, shallower waters along the Oregon coast rather than migrating to the Arctic like the majority of the Eastern North Pacific (ENP) gray whale population of 14,500.

Add WION as a Preferred Source

Also Read |Researchers finally discover enzyme that can slow ageing and boost health

Researchers from OSU's Marine Mammal Institute have been studying this PCFG subgroup since 2016, using drones to measure the whales' size. They found that a gray whale born in 2020 is expected to reach an adult body length about 1.65 metres (5.5 feet) shorter than a whale born prior to 2000. This represents over a 13 per cent decrease in the total length of these whales, which typically grow to 38 to 41 feet long.

"This could be an early warning sign that the abundance of this population is starting to decline, or is not healthy," said co-author of the study and an assistant professor at OSU KC Bierlich. "And whales are considered ecosystem sentinels, so if the whale population isn't doing well, that might say a lot about the environment itself."

Also Read |Scientists discover mitochondria's role in reducing obesity

The researchers believe this shrinking size could have cascading negative effects on the whales' health and reproduction.

Watch | Study: Secret aliens could be here on Earth already

The study also examined changes in ocean upwelling and relaxation patterns, which influence the availability of the whales' prey. The decline in whale size coincided with shifts in these oceanographic cycles, which the researchers suspect may be linked to climate change impacts on wind and temperature in the Northeast Pacific.

"Without a balance between upwelling and relaxation, the ecosystem may not be able to produce enough prey to support the large size of these gray whales," said co-author Leigh Torres, director of OSU's GEMM Lab.

Researchers are now focused on further investigating the environmental drivers behind the shrinking size of the PCFG gray whales, in order to understand the broader implications for the health of this population and the broader marine ecosystem.

(With inputs from agencies)