Unprecedented, record in the deep sea species of sharks fóliving fossils: We didn't even know it existed

In an unprecedented discovery deep within the ocean's abyssal zones, scientists have captured footage of live specimens of the "living fossil" known as the ghost shark (*Mitsukurina owstoni*) in their natural habitat. This marks the first time such observations have been made in situ, shedding new light on this elusive species and significantly expanding its known geographic range and depth distribution. The study, published in the *Journal of Fish Biology*, represents a major milestone in marine biology and has sparked considerable interest among researchers worldwide.

The ghost shark, often referred to as a "living fossil," is the sole surviving member of a lineage that dates back approximately 125 million years. First described scientifically in 1898 in the deep waters off Japan, the species had previously only been observed in captivity or caught in fishing nets, where survival rates were extremely low. Until now, all available images of the ghost shark came from these artificial environments, making the recent recordings in the open ocean particularly significant.

The research team documented two encounters with living ghost sharks in the central Pacific. The first occurred in 2019 near Jarvis Island, where a remotely operated vehicle named Hercules recorded a male specimen at a depth of 1,237 meters. Estimated to be around 3.43 meters long and approximately 51.5 years old, this observation was groundbreaking. A second encounter took place in 2024 in the Tonga Trench, where a female ghost shark was spotted at depths exceeding 2,000 meters. These findings extend the species' known depth range by nearly 700 meters and suggest a broader geographic presence than previously thought.

Aaron Judah, lead author of the study and a researcher at the School of Ocean and Earth Science and Technology (SOEST) at the University of Hawai‘i at Mānoa, emphasized the significance of the discovery. He noted that witnessing a healthy ghost shark in its natural environment was both rare and deeply meaningful. Additionally, he expressed surprise at how much deeper the species was found compared to previous estimates. This revelation could influence future conservation efforts and biodiversity assessments, as the ghost shark’s expanded range might necessitate updated management strategies.

The ghost shark exhibits unique hunting behavior that sets it apart from other deep-sea predators. It keeps its jaws retracted inside its skull most of the time but can rapidly project them forward in a powerful motion akin to a spring mechanism. This allows it to capture prey such as fish, squid, and crustaceans with remarkable speed and efficiency. Such adaptations highlight the species' evolutionary distinctiveness and its ability to thrive in extreme conditions.

The discovery has generated excitement among deep-sea researchers, including experts from the Minderoo-UWA Deep Sea Research Centre. The footage provides critical insights into the ghost shark’s ecology, behavior, and physiology, which were largely unknown due to the challenges of studying organisms in such remote and inhospitable environments. Scientists hope that further exploration will uncover more about the species’ life cycle, reproductive habits, and role in the deep-sea ecosystem.

With the confirmation of the ghost shark’s existence in new regions and depths, there is growing anticipation for additional studies that could refine our understanding of this ancient creature. Researchers are calling for increased investment in deep-sea exploration technologies to facilitate more discoveries of this kind. As one of the last remaining representatives of a lineage dating back millions of years, the ghost shark continues to intrigue scientists and underscores the vast mysteries still hidden beneath the ocean’s surface.