A peer-reviewed study published in early 2026 has placed a single accidental catch into 160 years of historical context, and the picture it reveals is stranger and more important than the headlines suggested.
Juvenile Caught: April 2023, Eastern Spanish coast
Size and Weight: 210 cm, ~80-90 kg juvenile
Records Reviewed: 1862-2023 (160-year study span)
IUCN Status: Vulnerable, Declining population
Study Published: Jan 2026, Acta Ichthyologica
On 20 April 2023, a crew of fishermen working off the eastern Spanish coast hauled something into their boat that they were not expecting: a juvenile great white shark, approximately 210 centimetres long and weighing between 80 and 90 kilograms.
They filmed it, reported it, and released it. Then the scientists got involved, and what began as a single unusual catch became a 160-year investigation.
New record of white shark, Carcharodon carcharias (Elasmobranchii, Lamniformes, Lamnidae), from the Mediterranean Spanish coast
José Carlos Báez · Miguel A. Puerto · Davinia Torreblanca · José L. Varela · Leila Carmona · David Macías
Published in open-access journal Acta Ichthyologica et Piscatoria in January 2026, this study placed the accidental 2023 catch within a comprehensive database of white shark records in Spanish Mediterranean waters dating back to 1862.
The study is the most thorough scientific review of Mediterranean great white shark presence ever conducted for the Spanish coast, and its conclusions challenge both the widespread assumption that great whites have “returned” to the region and the equally widespread assumption that they are entirely absent.
DOI: 10.3897/aiep.56.173786 · Open access
The study’s lead author, Dr. José Carlos Báez, describes the Mediterranean great white shark population using a term that captures both its reality and its mystery: a ghost population.
Great white sharks have not returned to Spanish waters, because they never fully left. The 160-year record shows a consistent, if extremely infrequent, pattern of appearances – not a disappearance and reappearance, but a continuous presence so sparse that it was all but invisible without systematic documentation.
This distinction matters enormously. The narrative of “return”, which many news headlines adopted when the footage of the 2023 catch circulated, implies that something has changed, that the sharks are coming back.
The peer-reviewed evidence suggests something more nuanced and, in some ways, more concerning: the sharks may never have left, but their numbers are so critically low that even their continued presence is ecologically tenuous.
What 160 Years of Records Actually Show
The 1862-2023 database compiled for the study represents every documented encounter (incidental catches by fishermen, sightings by researchers, and verified reports) of white sharks in Spanish Mediterranean coastal waters over that period.
The total number of records is modest: confirmed sightings and catches are measured in dozens across the entire 160-year span, not hundreds. This rarity is itself the key finding.
The most recent confirmed sighting before the 2023 catch was in 2018, when marine biologists from the Alnitak research team filmed a five-metre adult circling their research boat off the coast of Cabrera – the first confirmed great white in Spanish waters in over 30 years.
That five-year gap between the 2018 sighting and the 2023 catch is consistent with the historical pattern: appearances measured in years apart, not months.
The appearance of a juvenile in 2023 triggered a specific scientific question that the study addresses directly. “Determining the presence of juvenile individuals is of particular importance,” says Dr. Báez. “The occurrence of juvenile specimens raises the question whether active reproduction may be occurring in the region.”
The Mediterranean, it has long been hypothesised, may function as a nursery area for Atlantic great whites – females entering through the Strait of Gibraltar to give birth in the calmer, warmer waters, with juveniles remaining before eventually migrating out. The 2023 juvenile does not confirm this theory, but it does not contradict it either.
“These large marine animals have a fundamental role in marine ecosystems. 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.”
– Dr. José Carlos Báez, lead researcher, Acta Ichthyologica et Piscatoria, 2026
The Factors Driving Sightings Near Spain’s Coast
Climate change and shifting prey distributions
Rising sea temperatures in the Mediterranean (the sea has warmed faster than the global average over the past four decades) are altering the distribution of prey species including bluefin tuna, which has been recovering in Mediterranean waters following decades of overfishing protection measures.
Great white sharks are highly migratory apex predators that follow food sources across thousands of kilometres; as tuna populations rebuild in the western Mediterranean, the incentive for great whites to enter through the Strait of Gibraltar may be increasing.
Marine biologist Juan Carlos García has noted that sharks approaching Spanish shores are often following prey that precedes them, including fish escaping from aquaculture nets.
The nursery hypothesis
Expert Pablo García Salinas, speaking to El País, offered a specific hypothesis about why females in particular may enter the Mediterranean: “The females in the Atlantic could be using the Mediterranean as a kind of nursery: they would go there to give birth and, when the pups grew, they would leave through the Strait of Gibraltar.”
The logic is ecological: sheltered bays and protected coastal areas offer juvenile sharks fewer predators during their most vulnerable early months. If this hypothesis is correct, the 2023 juvenile catch represents exactly the kind of animal that this theory predicts.
Better documentation, not more sharks
A critical caveat in interpreting any apparent increase in sightings is the transformation of recording and reporting technology over the past decade.
Drones, high-resolution underwater cameras, smartphones, and social media have collectively made it far more likely that any unusual marine encounter will be documented and widely shared.
The Báez et al. study explicitly accounts for this reporting bias in its methodology, which is precisely why the 160-year historical record is valuable. Without that baseline, recent sightings cannot be meaningfully interpreted.
The Real Story: Not a Return – A Critically Endangered Population in Decline
The framing of these sightings as a “return” to Spanish waters does a disservice to the conservation reality.
Great white sharks are currently listed as Vulnerable on the IUCN Red List globally, and as critically endangered in the Mediterranean specifically, where overfishing, pollution, and habitat destruction have reduced their numbers to a population so small that it may struggle to sustain itself reproductively.
OCEARCH, the US-based research organisation that has collaborated with Spain’s Fundación Oceanogràfic on Mediterranean white shark studies, describes the situation starkly: “Ruthlessly persecuted, completely misunderstood, and now critically endangered.” Their expeditions to Mediterranean waters, crossing over 4,000 miles from the United States, found that confirmed sightings were rare even when specifically looking for them with advanced tracking equipment.
Beyond the Great White: Spain’s Actual Shark Fauna
While great white sharks dominate headlines, they represent just one of over 50 shark species present in Spanish waters.
The more ecologically and statistically significant shark encounters near Spain involve species that are considerably more common, and whose relationship with human beach activity is better documented.
Most Common in Spanish Waters
Blue Shark (Tintorera)
The blue shark (Prionace glauca) is the most frequently encountered shark species along Spanish coasts. In August 2023, a blue shark bit a man at Rabdells Beach in Valencia, causing minor injuries. In 2024, a blue shark in Menorca forced temporary beach closures in the Balearics. They typically chase squid and fish but are known for curious behaviour near swimmers.
Offshore, Canary Islands
Hammerhead Shark
Scalloped hammerhead sharks (Sphyrna lewini) appear regularly off the Canary Islands, particularly Gran Canaria. A hammerhead sighting prompted precautionary beach closures in 2024. They are generally non-aggressive toward humans. Critically endangered globally due to the fin trade.
Fast Pelagic Species
Shortfin Mako
The shortfin mako (Isurus oxyrinchus) is considered the fastest shark in the world, capable of reaching 45 km/h. It inhabits both Atlantic and Mediterranean waters around Spain. Listed as Endangered on the IUCN Red List. Rarely encountered near swimmers but considered potentially dangerous given its speed and size.
Atlantic Deep Waters
Basking Shark
The basking shark (Cetorhinus maximus), the world’s second-largest fish, appears periodically in Galician and Cantabrian Atlantic waters off northern Spain. Entirely harmless filter feeders, they can reach 12 metres in length and are occasionally mistaken for more dangerous species when seen from a distance.
Context on Shark Attacks in Spain
The International Shark Attack File records just 13 confirmed shark attacks in Spanish waters across the entire documented history of the country, with only 6 classified as unprovoked.
In September 2024, a German woman was fatally attacked by a shark near a catamaran in international waters south of the Canary Islands – the first fatal incident in the region in many years.
The incident underscores that while attacks are statistically rare, they are not zero. Spanish coastal authorities act quickly with precautionary beach closures when sharks are sighted near swimmers.
Why Finding a Ghost Shark Is Actually Significant
For conservationists, each confirmed record of a great white in the Mediterranean is not a cause for alarm – it is data in a dataset that has historically been far too sparse to draw reliable conclusions from.
Dr. Báez frames this explicitly: the presence of a juvenile is not a threat, it is information. It is evidence that a functionally extinct regional population may still have enough biological resilience to produce young, which means conservation intervention is not futile.
OCEARCH’s Chief Scientist Dr. Harley Newton articulates the broader ecological principle at stake:
“Sharks are keystone species in marine ecosystems. As top predators in the food web, they regulate prey populations and through that shape the diversity, abundance, and distribution of other species. This abundance and diversity is key to the health of marine habitats as well as human livelihoods.”
A Mediterranean without great whites is not just ecologically impoverished – it is structurally compromised. Losing an apex predator from a sea as enclosed and stressed as the Mediterranean would have cascading effects on every level of the marine food web.
The Báez et al. study concludes with a specific call: long-term monitoring programmes, combining direct observation with satellite tagging and environmental DNA techniques, are essential to understanding whether the Mediterranean ghost population has any realistic prospect of recovery. Without that data, conservation strategy is guesswork. With it, evidence-based interventions become possible.
Who Is Studying Mediterranean Great Whites
The organisations working to understand and protect the ghost population
OCEARCH – Expedition Save the Med
US-based research organisation that sailed over 4,000 miles to collaborate with Spanish and European scientists on Mediterranean white shark biology. Their satellite tagging programme aims to map migration routes and identify potential nursery areas.
Fundación Oceanogràfic (Spain)
Spanish marine research foundation partnering with OCEARCH and domestic institutions to study elasmobranch (shark and ray) populations in the western Mediterranean. Headquartered in Valencia.
Alnitak Research Centre
The Spanish research team that filmed the 2018 five-metre great white off Cabrera – the first confirmed sighting in over 30 years. Alnitak conducts ongoing cetacean and elasmobranch surveys in the Balearic Sea.
IUCN Shark Specialist Group
The body that maintains the global Red List status of Carcharodon carcharias as Vulnerable, with a declining population trend. Mediterranean great whites have been assessed as critically endangered at the regional level.
The great white sharks of the Mediterranean are not returning. They are still there – barely, and in numbers so small that the phrase “population” strains its own definition.
What the 2026 study has done is make the invisible slightly more visible, and given conservationists a clearer picture of what they are working to protect.
That juvenile, 210 centimetres long, accidentally caught and released back into the same sea its species has inhabited for millions of years, was not a warning sign. It was a data point. And in conservation, data points are hope.
Mediterranean Great White Shark · Carcharodon carcharias · Ghost Population · Spain · 2026 Scientific Review
Primary Scientific Sources:
phys.org – New record of great white shark in Spain sparks a 160-year review (Feb 2026)
ScienceDaily – A “ghost” great white shark reignited a Mediterranean mystery (Mar 2026)
SciTechDaily – Ghost 7-Foot Great White Shark Caught in the Mediterranean (Feb 2026)
Pensoft Publishers – Great white sharks in Spain: new record sparks a 160-year review (Feb 2026)
Gulf Great Whites / OCEARCH – Expedition Save the Med (2024–2025)
Additional Reporting:
Majorca Daily Bulletin – Balearic shark alert: New record great white (Feb 2026)
The Olive Press – Spain investigates great white sharks off coast (Aug 2024)
RightCasa – Are there sharks in Spain? Complete guide
Euro Weekly News – Spain’s Top 3 Most Dangerous Sharks 2025
A-Z Animals – A ‘Ghost’ Great White Shark Sighting Revives a Mediterranean Mystery
The peer-reviewed study referenced throughout this article: Báez et al., “New record of white shark, Carcharodon carcharias, from the Mediterranean Spanish coast,” Acta Ichthyologica et Piscatoria, 2026 (56: 27). DOI: 10.3897/aiep.56.173786. Open access. This article is an editorial overview for informational purposes and does not constitute scientific advice or official conservation guidance.
