🌅 A Humpback Whale in the Sacramento River

SOURCE

The Marine Mammal Center

WHAT TO KNOW

• An adult humpback whale named Rio was spotted breaching the water near the Rio Vista Bridge on the Sacramento River on September 16, about 60 miles from its typical home in the Pacific Ocean. Rio, known as CRC-11620 to researchers, entered the San Francisco Bay on September 15 before traveling east toward the state capital via the Sacramento-San Joaquin Delta, California's largest river delta. The unusual visitor was last seen on September 18 moving west via the Delta toward the San Francisco Bay, in what The Marine Mammal Center describes as a “very positive sign.” Experts say people should stay at least 100 yards away from Rio if they spot the whale.

WHY IT MATTERS

• Rio is well-known to researchers and enthusiasts, who have spotted the whale 15 times over the past 24 years as it swam off the coasts of California and Mexico. It’s unknown why Rio has ventured so deeply into the Delta, including whether the whale is simply passing through or if an underlying ailment or environmental issue spurred the strange trip. Experts say humpbacks frequent the San Francisco Bay this time of year, however, it’s unusual for a whale to take such a lengthy trip, particularly as the freshwater environment is outside its normal saltwater habitat.

CONNECT THE DOTS

• Surprisingly, Rio isn’t the first humpback to visit the Sacramento River. In 1985, a humpback named Humphrey made headlines after it swam within 30 miles of the state capital, prompting a high-stakes rescue when the freshwater environment began making him ill. Five years later, Humphrey beached himself on a mudflat in the San Francisco Bay, necessitating another rescue. In 2007, a mother-calf pair known as Delta and Dawn spent roughly three weeks in the Sacramento River Delta before returning to the ocean.