#balaenopteridae

Bryde's whale "Balaenoptera" brydei, front center

Cape long-beaked common dolphin Delphinus "delphis" capensis, back far right

With salema porgy Sarpa salpa, around whale

Humpback whales (Megaptera novaeangliae) feeding in Kenai Fjords National Park, Alaska, USA

Rice's Whale Balaenoptera ricei

It is restricted to the northeastern Gulf of Mexico, near the De Soto Canyon off the coasts of western Florida, Alabama, and eastern Louisiana. Alongside the vaquita, it is one of the most endangered cetaceans in the world, with an estimated population of 33.

Main threats are related to industrial and commercial activities within its habitat, including oil pollution, ship collisions, and underwater noise from seismic surveys and vessel traffic. The 2010 Deepwater Horizon oil spill killed nearly twenty percent of the species' population.

The Very Nice Rice's Whale

Rice's whale, also known as the Gulf of Mexico whale (Balaenoptera ricei) is a species of whale found only in the Gulf of Mexico. Originally the species was thought to be restricted to the northeastern part of the gulf, but it is now known to travel throughout the area. They keep close to the coast, and are rarely seen in waters deeper than 400 m (1300 ft). Originally, Rice's whale was considered a subspecies of Bryde's whale (B. edeni), but in 2021 genetic testing revealed it to be a completely separate species.

Gulf of Mexico whales are moderately sized; females grow to 12.65 meters (41.5 ft) in length and 13.87 metric tons (15.28 US tons), while males are slightly smaller at 11.26 meters (36.9 ft) long. Adults are plain grey and three long ridges on the top of their heads, which makes up a full quarter of their body length. The throat pouches and the underside of the tail are pink.

B. ricei follows a diel vertical diving pattern; they spend the day foraging near the bottom of the ocean, and rise to the surface at night. Though little is known about the diet of Rice's whales, it is suspected that they feed on lanternfish, hatchetfish, and silver-rag driftfish, which are abundant at great depths. Because they are baleen whales, they likely ingest large quantities of water and then filter their catch through their baleen plates.

The breeding habits of Gulf of Mexico have not been studied, but scientists extrapolating from information on the closely related Bryde's whale believe that B. ricei reproduce once every two or three years. Pregnancies may last 10-12 months, and subsequent nursing may last for up to 2 years. Scientists also estimate that Rice's whale reaches sexual maturity at 9 years old, and can breed year-round due to the warm, food-rich waters in which they live. Adults are often seen in small groups of 2-4.

Conservation status: The Gulf of Mexico whale is considered Critically Endangered by the IUCN. Less than 100 individuals exist in the wild; most scientists estimate the population to be no greater than 33. Their primary threats are boat strikes and the hazards included in drilling for oil, including underwater noise and oil spills.

Photos

National Marine Fisheries Service

Humpback whale (Megaptera novaeangliae) in the Johnstone Strait, Canada