Why Are Gray Whales Dying Off?

Some scientists believe there may be too many whales for the population to sustain itself. Others say this explanation of “overcapacity” and “natural causes” overlooks the gantlet of hazards that grays now face — including ecosystem alteration, ship strikes, entanglement in fishing gear, plastics pollution, disease, ocean acidification and loss of kelp forests.

Air Guns Threaten Right Whale Extinction

In June 2017, NOAA Fisheries published proposed whale protections for the surveys. By winter the division’s biologists saw a problem: The protections for the North Atlantic right whale were too weak and put airguns in their direct path.

The agency had proposed a seasonal ban on using airguns up to 47 kilometers (about 29 miles) from shore between November and April, when the whales were known to migrate and give birth along the mid- and south-Atlantic coast.

But peer-reviewed research led by a NOAA Fisheries analyst concluded the whales were traveling farther from shore than ever before — and directly into the path of the proposed survey activity. A draft report for the Navy reached a similar conclusion.

Warming Oceans Increasing Whale Entanglements

“With the ocean warming, we saw a shift in the ecosystem and in the feeding behavior of humpback whales that led to a greater overlap between whales and crab fishing gear,” said Jarrod Santora, a researcher in applied mathematics at UCSC’s Baskin School of Engineering and first author of the study, published January 27 in Nature Communications.

193 Gray Whales Found Dead

So far, the cause of the die-offs remains a mystery, though theories include starvation from lack of food, or a disease that mimics chronic wasting disease. Teams of scientists are investigating what the casualties mean for the gray whale population as a whole. But some also fear that the deaths could be part of a larger trend as animals struggle to adapt to climate change. Said Ferguson: The “gray whales are just one piece” to the environmental puzzle.