The Impact of Deepwater Horizon on one of Earth’s Rarest Whales

Deepwater Horizon is one of the most infamous oil spills in history. But while many people remember the tragedy and how it affected the Gulf of Mexico in 2010, most probably don’t know that the spill nearly wiped out a distinctly American whale species: the Rice’s whale. 

Why? Because we didn’t discover that this whale existed until 2021. 

Now, nearly 15 years after the catastrophic spill, Rice’s whales teeter on the brink of extinction, and we can track some of their struggles back to that fateful day.

The Mysterious Marine Mammal 

Previously thought to be a population of Bryde’s whales, the Rice’s whales we had long spotted in the Gulf were not found to be a distinct species of large whale until 2021. This determination came after scientists examined the anatomy and genetics of a whale found stranded in the Florida Everglades in 2019. The new species was named the “Rice’s whale” after scientist Dale W. Rice, who in 1965 was the first to write about the presence of what was thought to be Bryde’s whales in the Gulf.

In recent years, we’ve learned a few things about the species. Rice’s whales, which are a species of Baleen whale, live exclusively in the Gulf of Mexico and are a whopping 40 feet in length, about the size of a school bus. They are so rare that there is little else known about their lifespan, behavior, and diet. But since Rice’s whales are Baleen whales, they have baleen plates in their mouths that allow them to filter feed on prey like krill, schooling fish, and copepods. 

Based on what little we have discovered about this mysterious marine mammal, we think they likely dive to the seafloor to feed on schooling fish during the day, and stay within 50 feet of the water’s surface at night. Additionally, they are thought to be fully mature at the age of nine. 

We’ve also discovered a grim fact: the Deepwater Horizon spill devastated the species. 

The Infamous Tale of Deepwater Horizon 

On April 20, 2010, the Deepwater Horizon oil drilling rig – located 52 miles off the Louisiana coast in the Gulf of Mexico – exploded. This explosion started the largest oil spill in U.S. history, lasting 87 days and spilling 134 million gallons of oil into the clear blue waters of the Gulf. 

Following this catastrophe, the nation watched as teams of volunteers, scientists, and many more worked to free sea turtles and seabirds from suffocating coats of oil. In spite of their work, tens of thousands of marine animals died as a result of the spill, including sea turtles, dolphins, whales, fish and invertebrates. Every single species of cetacean – a grouping of marine mammals that includes whales, dolphins and porpoises – that lived in the Gulf were found to be exposed to oil. 

Back in 2010, counting those losses was a grim task. But while scientists knew the damaging impacts oil had on whales in the Gulf, they didn’t know at the time the full impact this oil exposure had on the yet-undiscovered Rice’s whale. 

The Lasting Impact on Rice’s Whales

Since Rice’s whales were discovered so late in the game, scientists have only just begun piecing together how the Deepwater Horizon spill affected this species. 

When a Rice’s whale comes into contact with oil, it can cause irreparable harm. Oil can coat the baleen plates inside their mouth that they use to filter feed. This subsequent coat of oil can make it difficult for Rice’s whales to eat and can also cause them to swallow oil – leading to illness or death. Inhalation of oil can also restrict breathing, and ingestion of oil can reduce their ability to fight off disease or reproduce.

It was no surprise then, that when 134 million gallons of oil spilled into an estimated 48 percent of the Rice’s whale habitat, their population declined by up to 22 percent. Even nearly 15 years later, Rice’s whales are likely still facing reproductive problems as a result of the spill. 

The Future of Rice’s Whales

Today, with the effects of the oil spill still lingering, there are fewer than 100 Rice’s whales left on Earth. With a population so low, even a single Rice’s whale death is devastating to their population – and the whales face risk every day. 

Their only home, the Gulf of Mexico, is prime drilling grounds for oil companies, and every time we drill, we run the risk of oil spills similar to Deepwater Horizon that could once again expose marine life to oil. 

Day-to-day offshore drilling operations and other human activity in the Gulf also pose threats to the whales: boat strikes, entanglements from fishing gear and underwater noise could all harm, injure or kill a Rice’s whale. 

Thankfully, hope is not lost – there are things we can do to help save the species. We can protect their most important habitat from oil and gas drilling, slow down ships, reduce noise pollution and invest in innovative new fishing gear. In the long run, we can stop drilling off our coast entirely – only then will Rice’s whales be truly safe from another disaster such as  the Deepwater Horizon catastrophe. 

For now, Rice’s whales need us to tell their story, to highlight the important role they play in the Gulf’s vibrant ecosystem – and for us to urge lawmakers to do what it takes to protect America’s most secretive whale. With enough support, the news around this mysterious marine mammal can be less morose and simply just marvelous.