The fish was discovered in the depths of the South China Sea. Dubbed Branchiostegus sanae, or the “Mononoke tilefish,” this deep-sea dweller lives at depths of up to 300 meters below the surface. The fish was named after San, the fierce protagonist of Studio Ghibli’s Princess Mononoke (the iconic 1997 film by Hayao Miyazaki) due to its striking facial markings.

A special tilefish

Tilefish are bottom-dwelling marine fish that inhabit sandy and muddy seabeds on the edges of continental shelves. They are typically found at depths ranging from 20 to 200 meters, but some species venture deeper. Deepwater tilefish are sometimes sold in food markets in East Asia, and in 2021, marine biologists noticed unusual specimens being sold in online seafood markets. These specimens had a distinct cheek pattern, unlike any known species.

Intrigued, a team from the South China Sea Institute of Oceanology and other institutions set out to investigate. By collecting and analyzing specimens from fishermen in 2023, they confirmed that this was indeed a new species. DNA sequencing of the fish confirmed a distinct genetic lineage.

Much like the film’s heroine, the face of the Mononoke tilefish is marked by stripes. Its body is adorned with approximately sixteen dark vertical stripes. But its most distinctive feature is the red stripe running below its eye, contrasting sharply with a white band extending to its upper jaw. This facial pattern is what inspired its name, as it resembles San’s tribal markings, a symbol of her connection to nature and her warrior spirit.

Aside from its vivid markings, B. sanae boasts translucent grayish dorsal fins, yellow predorsal ridges, and a unique combination of fin and scale characteristics that set it apart from its relatives. Unlike other tilefish, it lacks black spots at the base of its scales, and its tail fin has a distinctive mix of pale orange, yellow, and dark gray hues.

A symbolic name

The choice of name for this new species is not just a whimsical tribute to a beloved animated film. It carries a deeper message. In Princess Mononoke, San fights to protect the forest and its creatures from destruction caused by human greed. Her story is a powerful allegory for environmental conservation.

By naming the fish after San, scientists hope to highlight the importance of marine conservation, especially in deep-sea ecosystems that are increasingly threatened by overfishing, habitat destruction, and climate change. Lead author of the study Haochen Huang said:

“In Princess Mononoke, San is a young woman raised by wolves after being abandoned by her human parents. She sees herself as a part of the forest and fights to protect it.

“The film delves into the complex relationship between humans and nature, promoting a message of harmonious coexistence between the two: something we hope to echo through this naming.”

Deep-sea fishing, trawling, and habitat degradation pose significant threats to species like the Mononoke tilefish. Many deep-sea fish are slow-growing and have low reproductive rates, making them particularly susceptible to overfishing. Furthermore, many species in the deep ocean we haven’t even discovered yet. Without proper management, unique species could be wiped out before we even have a chance to discover them.

The Mononoke tilefish serves as a reminder that many species remain unknown to science, and protecting the ocean means protecting the mysteries it still holds. This is particularly true in the South China Sea, one of the most important biodiversity hotspots on the globe.

“In the last decade, only two new species of this genus have been described, but both of them come from the South China Sea. Reviewing the distribution of all Branchiostegus species, we find that all except B. semifasciatus are distributed in the Indo-West Pacific region. This region is also considered the center of global marine biodiversity,” the researchers conclude.

The study was published in ZooKeys.