Gray whales shrinking in size along Pacific coast, study shows

A new study shows gray whales are shrinking in size along the Pacific Northwest coast throughout the last 20-30 years. This trend of declining sizes has raised concerns among the scientific and biological community.

According to a recent study conducted by Oregon State University (OSU) researchers, gray whales in this area have lost an average of 13% of their body length since 2000.

It focused on the Pacific Coast Feeding Group (PCFG), a subgroup of about 200 gray whales. They spend their summers feeding in the warmer, shallow waters off the coast of Oregon rather than migrating to the Arctic like most of the 14,500 gray whales that make up the Eastern North Pacific (ENP) population. PCFG whales have smaller skulls and flukes than ENP whales.

OSU’s Marine Mammal Institute researchers have been utilizing drones to measure whales’ size. This is part of their research of this PCFG subgroup since 2016. It showed a gray whale born in 2020 is predicted to grow around 5.5 feet shorter as an adult than a whale born before 2000.

These whales usually reach a maximum length of 38 to 41 feet. Hence, the expected size of gray whales (5.5 feet) shows a decrease in size by 13% in their overall length.

KC Bierlich is an assistant professor at OSU and co-author of this research study. He said this research may indicate that the whale population’s abundance is beginning to decrease. Gray whale species may also not be in good health.

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According to KC, gray whales are indicators of an ecosystem guardian. So, a declining whale size or population may hint at significant environmental problems.

However, researchers attribute changes in oceanographic cycles of the Pacific Northwest coast to the shrinking size of gray whales. Climate change might have affected the wind and temperature of oceanographic cycles.

Moreover, researcher Leigh Torres said the ecosystem of the Pacific Northwest coast may not be able to produce enough prey to support the large size of these gray whales. It may also be another reason for the shrinking size of these whales.