Sperm whale's slow death trapped in maze-like Japanese bay raises alarm over impact of global warming

The slow demise of a stray whale in Osaka Bay has alarmed experts who see it as a casualty of global warming.


Whales Losing Their Way More Frequently

According to Yasunobu Nabeshima, a visiting researcher at the Osaka Museum of Natural History, the phenomenon of whales losing their way has become more frequent due to global warming. He explains that the temperature differential between the Pacific Ocean and Osaka Bay has decreased, causing the powerful Kuroshio Current to propel whales from deep ocean waters into the shallow waters along the coast. This has resulted in incidents like the recent tragic case in Osaka Bay, which marked the second in as many years.

The Challenging Environment of Osaka Bay

Osaka Bay, serving as the gateway to Japan's third-largest city, is a maze of artificial islands, landfilled peninsulas, and various industrial structures. This complex environment with its numerous nooks and crannies, wharves, and breakwaters has proven to be a death trap for marine mammals like sperm whales. The bay's structure makes it nearly impossible for the creatures to navigate their way back out to the open water. Recent incidents have also seen short-beaked common dolphins and sea turtles becoming stranded in the area.

Struggles and Solutions

The most recent casualty, a severely emaciated male sperm whale weighing over 30 metric tons and measuring 50 feet in length, was recovered and temporarily buried as it was deemed more cost-effective than hauling the carcass out to sea. Local governments often bear the financial burden associated with dealing with stranded whales, with offshore burials costing significantly more than land burials. In the case of last year's stranded sperm whale, the offshore burial cost taxpayers over half a million dollars.

Efforts are being made to protect these majestic creatures. Scientists propose the use of sensor-activated 'acoustic deterrent devices' at the Kii Strait, the entryway to the Inland Sea, to prevent whales from venturing too close to the coastline. These measures aim to keep the whales safe from harm caused by their navigation mishaps.