The Mediterranean Sea is a semi-enclosed basin connecting three continents. While popular for tourism, its waters support a diverse population of cartilaginous fish, including sharks. Contrary to popular perception focused on large predators, the majority of the shark fauna consists of smaller, less-known species that inhabit deep-sea environments. This sea hosts a significant portion of the world’s shark species, although their populations are currently facing substantial pressure.
Characterizing the Mediterranean Shark Habitat
The Mediterranean is connected to the Atlantic Ocean only through the narrow Strait of Gibraltar, making it a unique and isolated environment. This geographical bottleneck contributes to distinct oceanographic conditions, including a relatively low-nutrient environment compared to open oceans. The basin features extreme depth variations, with trenches reaching over 15,000 feet, creating a wide range of habitats for sharks.
The deep-water environment is permanently warm, maintaining a temperature of around 55 degrees Fahrenheit (13 degrees Celsius) at depth. Over 40 different shark species have been recorded, but many of these are rare or only occasional visitors. The division between the western and eastern basins also influences species distribution, with some populations showing regional specialization.
Major Categories of Mediterranean Sharks
The composition of the Mediterranean shark population can be grouped into categories based on their preferred habitat and size. A large portion of the species consists of smaller, bottom-dwelling sharks, which are rarely encountered by humans. These deep-water and benthic species include various types of catsharks and dogfish, which typically reside on the continental shelf and slope. The Small-spotted Catshark, for example, is a common bottom-dweller, rarely exceeding three feet in length, that hunts small fish and invertebrates near the seabed. The Bluntnose Sixgill Shark is another inhabitant of the deeper zones, sometimes reaching lengths of 16 feet, and it is known to migrate vertically to shallower waters at night to feed.
Coastal and medium-sized sharks are more likely to be found closer to the continental shelf but still generally avoid congested coastal areas. The Sandbar Shark is a common example, characterized by its high dorsal fin and preference for sandy or muddy bottoms in bays and harbors. This species can grow to about eight feet long and is often a target of fisheries throughout the region. Another medium-sized species is the Tope Shark, or School Shark, which has a slender body and is known for forming large, segregated groups.
The third category includes large pelagic species, which spend most of their lives in the open ocean but migrate into the Mediterranean. The Blue Shark is the most frequently observed large species, often comprising a majority of those encountered in scientific surveys. These slender sharks can reach ten feet in length and are generally found in cool, deep waters away from the coast. Historically, the Great White Shark was a resident, though verified occurrences are now extremely uncommon. Other large pelagic visitors include the Shortfin Mako and various species of Hammerhead Sharks, such as the Scalloped Hammerhead.
Current Status and Likelihood of Encounters
The Mediterranean Sea is recognized as having the highest proportion of threatened shark and ray species globally, with over half of the native species facing an elevated risk of extinction. This severe decline is largely attributed to intense fishing pressure, resulting in both targeted catches and high rates of accidental bycatch. Species like the Blue Shark, Shortfin Mako, and Great White Shark are all listed in threatened categories due to their slow growth, late maturity, and low reproductive rates, making them vulnerable to overexploitation.
Despite the presence of numerous species, the likelihood of a human encounter with a shark in the Mediterranean is statistically low. Historically, unprovoked incidents have been exceedingly rare, with only a few dozen confirmed cases over the last century and a half. The greatest risk to Mediterranean sharks comes from human activity, not the reverse, as conservation efforts struggle to keep pace with population declines.