The whales of the Gulf of Mexico

World Whale Day is on February 19. In recognition, we’re highlighting some of the whales living in our backyard of the Gulf of Mexico. 

These loveable and awe-inspiring creatures are members of the Cetacean family, which includes toothed whales (odontoceti) like dolphins, belugas, sperm whales, and beaked whales, as well as baleen whales (mysticeti) like the Right whale. Whales tend to migrate thousands of miles across most of the earth’s oceans, but here are some facts about the frequent cetacean visitors of the Gulf Coast!

North Atlantic Right Whale

Per its name, the right whale is most often found in the North Atlantic, but some do come as far as the Gulf of Mexico. The Right whale gets its name from the early whalers dubbing it the “right whale” to hunt, although it is now illegal to hunt under the Endangered Species Act. Unfortunately, current estimates report that only about 350 North Atlantic Right Whales remain, and the IUCN Red List labels them as Critically Endangered. 

These whales are most easily identified by the white patches, also known as callosities, that grow on their heads. These patches of skin are thicker than the rest and contain keratin, the same substance that makes up our hair and nails! Right whale callosities are also often host to a species of crustaceans called whale lice or cyamids which feed off the whale’s skin without harming it. These callosities are also useful for identifying individuals because each whale’s pattern is unique. Right Whales use baleen, a filter-like structure made of keratin, to strain through water for food. 

Sperm whale

The Sperm Whale is the largest of the toothed whales, and is roughly the 7th heaviest whale overall. These whales have a large range of migration, and have been observed in all of the world’s oceans. These whales used to be hunted for the oil located in their heads, which was used for a variety of purposes including lamps and lubricants. After the 1986 International Whaling Commission moratorium, the population of Sperm Whales has begun to recover, it is still labeled as vulnerable on the IUCN Red List.

Orcas

Unlike the rest of the whales on this list, the Killer Whale or Orca is actually a member of the family Delphinidae, a subgroup of toothed whales (Odontoceti) that includes most species of dolphins. It can be found in all of the world’s oceans, generally preferring the higher latitudes, but there have been sightings of Orca pods in the Gulf of Mexico. While they can eat a wide range of foods, Orca have been observed forming social bonds, as well as unique behaviors and hunting strategies within their social groups. While the species as a whole is not classified under the Red List, they are protected by the Marine Mammal Protection Act, and some local populations are considered threatened or depleted, such as the “Transient” population of whales after the Exxon Valdez spill.

Bryde’s Whale

Bryde’s Whales (pronounced “broodus” after its norwegian namesake) prefer warmer waters, making them more common visitors to the Gulf. They share some visual similarities with Sei whales, however Bryde’s whales have 3 ridges on top of their heads where Sei whales have only one. Bryde’s whales were not major targets during the historical whaling boom, but they are prone to ship strikes since they frequent warmer coastal regions. The Bryde’s Whale is labeled as a species of Least Concern on the IUCN Red List

Rice’s Whale

While this species was initially assumed to be a Gulf Coast variant of Bryde’s whale (Balaenoptera brydei), studies have recently identified significant differences in genes and unique skull structures. Unlike its relatives in the Balaenoptera family which have one blowhole on their upper jaw, both Rice’s and Bryde’s whales have three. Rice’s whales are the only whales on this list to exclusively be sighted in the Gulf of Mexico, as they are believed to not embark on long distance migrations. Unfortunately, their small population size and distribution also means that they’re at a higher risk of extinction. According to NOAA, there are likely fewer than 100 individuals remaining in the species. 

Threats to whales in the Gulf

Unfortunately, our local whales are often harmed by human activities in the gulf of Mexico. Being such large creatures, they are often at risk of being hit by both large ships and personal watercraft like jet skis. For species that like to migrate close to human-populated areas of the coastline, this becomes an even greater risk. To reduce the risk of fatal collisions, NOAA works to communicate whale sightings and places limits on the speed of ship traffic when they might be present. Similarly, whales can get caught in fishing equipment, causing a variety of issues. Entangled whales often struggle to reach the surface to breathe, and often suffer physical injuries from the equipment.

Another risk to whale populations is our use of equipment offshore for energy production. Even before anything is constructed, the survey equipment used to map the ocean floor for drilling can physically damage whales’ hearing. These surveys use pressurized air guns to send vibrations to the seafloor and read the reflected sound to graph the geology of the seafloor. Unfortunately, the volume of these vibrations and the pressure released can often cause physical harm to aquatic wildlife. 

Finally, whales in the gulf are particularly susceptible to harm from oil spills. These spills, along with the chemicals used to clean up after them can cause infections and irritation, coat their baleen, and affect reproduction. Even when the platforms are not directly within regions populated by whales, spills can still spread out into whale habitats. For example, during the Deepwater Horizon spill, NOAA says that “nearly half of the oil spill footprint overlapped with the [Rice’s] whales’ habitat. As a result, it is estimated that their population decreased by 22 percent.”