Whale Species Recently Discovered to Favor Non-Endangered Prey, However, the Species Itself Remains Endangered

The most picky whales in the world. Their favorite meal is small, plentiful fish, and scientists say that, despite its commonness, this fish should be considered as part of conservation strategies for the endangered whale.

Found exclusively in the Gulf of Mexico, Ray’s whales are a newly discovered species that was once thought to be a subspecies of Bryde’s whale that is more geographically diverse. It was only two years ago that scientists announced, after examining the genetic and anatomical evidence, that bay whales were in fact their own distinct species. Only 50 ray of whales are believed to feed primarily on Ariomma bondi, more commonly called a floating silverfish, according to new research led by the FIU.

Identifying their primary prey is an important first step in accelerating the conservation of this newly identified species, according to FIU marine biologist Jeremy Kiska, lead author of the research. He says that while their primary prey is plentiful today, that could easily change in an area heavily affected by people and industrial activity.

“Cedar whales need high-quality food, which could make them more vulnerable to climate change and fisheries impacts if their main prey is affected in any way,” Kiska said. “Previous research shows that being a specialist makes you more vulnerable, especially if your preferred prey experiences decrease.”

Cedar whales engage in deep diving to search for food, which is an energy-intensive effort. While silver-cloth floating fish were not the only fish in the rice whales’ diet, they were the primary prey. Small fish are high in calories, which can give whales more energy. They also swim in large schools, which makes them an easier target. Either of these factors, or perhaps both, make it an ideal meal for whales.

“These research findings suggest that rice whales are more vulnerable than we thought,” said marine scientist Mike Haithose, executive dean of the FIU’s College of Arts, Sciences and Education and co-author of the study. “We need to make sure that we protect their habitat and the habitats of their prey.”

The research began in 2017, which means the team was unaware of the species distinction that would be revealed in 2021. The discovery of whales in the Gulf were actually a new species to science only intensified Kiszka’s interests in large marine mammals. He plans to continue researching cedar whales and help improve scientific knowledge of the species in an effort to save the species from extinction.

The research was published this week in Scientific reports. In addition to Kiszka and Heithaus, the research team also included Michelle Caputo of Rhodes University in South Africa; Joanna Vollenweider of Auke Bay Laboratories in Alaska; Laura Aichinger Dias of NOAA’s National Marine Fisheries Service (NMFS) and the University of Miami; and Lance Garrison from NMFS.