Evidence is mounting that an exceedingly rare whale, unique to the Gulf of Mexico, ranges farther west than previously thought, prompting new worries about the dangers it faces from heavy ship traffic and other industrial activities near Louisiana and Texas.
Scientists spotted two of the approximately 75 remaining Rice’s whales during an aerial survey of marine animals in the western Gulf last month. National Oceanic and Atmospheric Administration researcher Laura Dias saw one of the bus-size whales breaching the surface about 55 miles from Corpus Christi, Texas on April 11.
“I felt a wave of excitement and relief,” she said, describing the culmination of an “intense effort” to photograph the endangered whale species west of Louisiana. Found to be a distinct speciesjust three years ago, the shy, deep-diving Rice’s whale remains largely a mystery. Scientists are racing to learn the basics, including how the whale eats, breeds and communicates, before the species goes extinct.
Recent audio recordings have also offered proof of the whale’s frequent travels in the western Gulf. A NOAA-led analysis of underwater sounds detected the whale’s distinctive “long moan” several times off the coasts of Louisiana and Texas, and offered the first evidence of the whale in Mexico’s waters.
“This is new knowledge and is critical for our understanding [of the whales] given how heavily industrialized that portion of the Gulf is,” said Melissa Soldevilla, a NOAA scientist who led the acoustical research.
The photos and recordings have upended the theory that the Rice’s whale rarely strayed from DeSoto Canyon in the eastern Gulf near Alabama and Florida.
Ships, oil and plastic
The new evidence was troubling for Michael Jasny, a marine mammal protection expert with the Natural Resources Defence Council.
"The vast majority of the risk this species faces is from vessel strikes,” he said. “There’s so much more vessel traffic in the central and western Gulf than there is in the east.”
Texas and Louisiana have several busy shipping hubs, including Houston, the U.S.’s fifth-largest container port, and Port Fourchon, which serves nearly all of the Gulf’s 3,200 active oil and gas structures.
Rice’s whales are “severely vulnerable” to ship strikes because they rest just below the surface at night, Jasny said. This behavior contrasts with most whales, which tend to be nocturnal. A dozing whale is less likely to notice an oncoming vessel, and the vessel’s crew is less likely to spot the whale in the dark.
In 2021, environmental groups petitioned NOAA to set a 10-knot speed limit around DeSoto Canyon. The proposal drew about 75,500 comments and strong opposition from the shipping and oil industries. In October, NOAA denied the petition in favor of an effort to get vessels to slow down voluntarily.
Jasny noted that NOAA adopted a similar 10-knot speed limit along the East Coast to protect the North Atlantic right whale, a species that’s also endangered but has a population that’s likely three times larger than the number of Rice’s whales.
Gulf Coast political leaders have expressed opposition to other measures to protect the whale, including a NOAA proposal to designate 28,000 acres in the Gulf as a new critical habitat.
On May 1, U.S. senators John Kennedy and Bill Cassidy of Louisiana and Cindy Hyde-Smith and Roger Wicker of Mississippi wrote a letter to NOAA warning against “unnecessary measures for the Rice’s whale at the expense of communities along the Gulf of Mexico.” The Republican senators believe whale-related restrictions on shipping and oil and gas development “would directly harm the economic activity and jobs.”
Rice’s whales are also threatened by oil spills, ocean trash, entanglement in fishing gear and noise, especially blasts from seismic airgun surveys that companies use to find offshore oil deposits.
BP’s Deepwater Horizon oil disaster in 2010 killed nearly 20% of the Rice’s whale population and likely caused widespread health problems and pregnancy failures, according to a NOAA-led assessment.
The growing problem of plastic pollution has also proved fatal for at least one of the whales. In 2019, a 38-foot-long male that washed up on a Florida beach was found to have been killed by a jagged piece of plastic that became lodged in its stomach.
A dead Rice’s whale washed up on a Florida beach in 2019. It was found to have been killed by a plastic fragment lodged in its stomach. Credit: National Park Service
Discovering a new species
The whale’s death had a silver lining, though. The carcass was a treasure trove of information for scientists and helped prove that the Rice’s whale is a distinct species.
Scientists had long thought Rice’s whales were a Gulf-dwelling variety of Bryde’s whales, another endangered species that ranges widely in the Atlantic and Pacific oceans. Rice’s and Bryde’s whales look almost identical. They grow to around 55 feet, weigh about 30 tons, use baleen to filter-feed and are part of what NOAA calls the “great whales,” a group that includes humpback, sperm and blue whales. But the dead specimen offered a rare opportunity to get a close look at the Rice’s whale’s organs, skeleton and DNA, all of which revealed clear differences.
A growing body of research indicates the whales’ behavior also sets them apart. While Bryde’s whales feed near the surface on a range of seafood, including krill, shrimp, herring and other small fish, Rice’s whales like to dive deep for one particular menu item: the silver-rag driftfish. And, unlike the free-ranging Bryde’s whales, Rice’s whales are homebodies, preferring to stick to the Gulf’s warm waters.
Some scientists wanted to name the newly-discovered species the “Gulf of Mexico whale” or the “American whale,” because it lives almost entirely in U.S. waters.
In the end, the NOAA scientists who confirmed the whale was a distinct species decided to name it in honor of Dale Rice, a biologist who first recognized some 60 years ago that the Bryde’s whales in the Gulf seemed different from other Bryde’s whales.
Regardless of what they’re called, Jasny hopes more Americans – especially Gulf Coast residents – come to appreciate this massive and mysterious animal, and understand how close it is to vanishing forever.
“This is a really remarkable species,” he said. “They’re unique to the Gulf and even the U.S. We want to make sure people realize how unique they are and how dependent they are on the habitat of the Gulf.”
This article first appeared on Verite News and is republished here under a Creative Commons license.