Rare Great White Shark Encounter Reveals Elusive, But Persistent “Ghost” Population In Mediterranean

Great white sharks, also known simply as white sharks (Carcharodon carcharias), are a fascinating but fragile species. For all the fear they have gained in popular culture over the decades, they are actually crucial predators that help maintain the health of the world’s oceans. They do this by controlling prey populations, which helps coastal seagrass and kelp ecosystems – both of which are not only excellent habitats for marine life but also carbon sinks.

Although white sharks have historically had widespread distribution across the planet, the species has suffered significant population loss. As such, they are currently classified as a Vulnerable species by the International Union for Conservation of Nature (IUCN).

When it comes to the Mediterranean Sea in particular, white sharks have been something of a mystery. Their presence has largely been inferred from sporadic sightings, bycatch, or historical records. So, it was quite shocking when, on April 20, 2023, a juvenile great white shark was accidentally caught by local fishers off the coast of the eastern peninsula within the Spanish Exclusive Economic Zone. The fish was around 2.1 meters (6.9 feet) in length and weighed around 80 to 90 kilograms (176 to 198 pounds).

Given the scarcity of white sharks in the region, any encounter with one is extremely significant for scientific and conservation purposes. There is very little data available to researchers on young and juvenile specimens in the Mediterranean, though for some time, the Strait of Sicily and the Gulf of Gabès have been considered breeding grounds for white sharks. It is possible that the Bay of Edremit in the northwestern Aegean Sea is also a nursery ground, as 11 newborn white sharks have been recorded there since 2008.

However, the presence of the juvenile white shark in the Spanish Mediterranean prompted some important questions – basically, was this shark native to the region or had it migrated from the central Mediterranean?

To investigate this, researchers undertook a deep dive into past records covering the years between 1862 and 2023. Their analysis revealed that although white sharks are an elusive “ghost” population, they maintain a continued presence in the Spanish Mediterranean waters. The results demonstrate a persistent but infrequent occurrence, with sightings being exceptional.

“Determining the presence of juvenile individuals is of particular importance,” Dr José Carlos Báez, the study's lead researcher, explained in a statement. “The occurrence of juvenile specimens raises the question whether active reproduction may be occurring in the region.”

In reference to the unfair fear great white sharks generate, Báez quoted the famous observation by H.P. Lovecraft, that “the oldest and strongest emotion of mankind is fear, and the oldest and strongest kind of fear is fear of the unknown.” He hopes that scientific clarity will help remedy this.

“By shedding light on the biology and ecology of the great white shark, research can help replace unfounded myths with genuine understanding,” Báez said.

As white shark populations continue to decline, there is a greater need for long-term observation programs that help us understand the species’ biology in the Mediterranean. Combining data from direct sightings with advanced tracking methods will help scientists to develop evidence-based conservation strategies for the most iconic predator in the seas.

“The main idea I want to convey to the public is that these large marine animals have a fundamental role in marine ecosystems,” Báez added. “As highly migratory pelagic species, they redistribute energy and nutrients across vast distances. They serve as nature’s scavengers - by consuming carrion, they keep ecosystems clean. Even in death, their descent to the seafloor provides a critical pulse of nourishment for deep-sea communities.”

The study is published in Acta Ichthyologica Et Piscatoria.