The Mediterranean Sea, often celebrated for its inviting waters and coastal beauty, is also a dynamic marine environment that hosts a variety of shark species. Many people are unaware that this enclosed sea, connecting three continents, provides a home for these diverse and often misunderstood creatures. Sharks are an integral part of the Mediterranean’s rich biodiversity, contributing to the health and balance of its marine ecosystems.
Notable Shark Species of the Mediterranean
The Mediterranean Sea is home to at least 47 different species of shark, with some being more commonly encountered than others. Among the larger and more recognizable species is the Great White Shark (Carcharodon carcharias), though sightings are rare. These powerful predators can reach lengths of up to 20 feet and weigh over 2,000 kilograms, possessing a torpedo-shaped body and sharp teeth. While capable of living up to 900 meters deep, they typically hunt between 3 and 25 meters, preying on small whales, dolphins, and seals. Historically, only 23 documented Great White Sharks have been seen in the last 50 years, often near the Strait of Messina.
Another notable resident is the Blue Shark (Prionace glauca), a slender and graceful species found throughout the Mediterranean. Identified by its vibrant blue coloration and long, sleek body, it can grow up to 12.5 feet long. Blue sharks are adaptable, swimming in various waters and feeding on squid, fish, and crustaceans.
The Shortfin Mako Shark (Isurus oxyrinchus) is recognized as one of the fastest sharks, capable of reaching speeds of up to 75 km/h. Belonging to the same family as the Great White, this shark can grow to 4.5 meters in length and weigh up to 750 kilograms. Shortfin makos are pelagic, meaning they inhabit the open ocean, and primarily feed on large tuna, swordfish, and even small whales.
Hammerhead Sharks (Sphyrna spp.), including the Smooth and Scalloped Hammerheads, are distinctive for their flattened, hammer-shaped heads. This unique head shape aids in scanning the seafloor for prey using sensitive electroreceptors. Hammerheads in the Mediterranean can reach up to 16 feet (Smooth Hammerhead) or 14 feet (Scalloped Hammerhead) in length. They typically feed on cephalopods, rays, sardines, and mackerel, often found in warm coastal areas.
The Thresher Shark (Alopias superciliosus) is characterized by its exceptionally long, whip-like tail, which can be as long as its body. This pelagic shark uses its tail to stun schools of fish before consuming them. Thresher sharks also possess large eyes, which assist them in hunting in low-light conditions. Growing to about 3-4 meters, they are generally shy and pose no danger to humans.
Sand Tiger Sharks (Carcharias taurus), also known as Grey Nurse Sharks, are slow-moving and can reach 3.5 meters in length and weigh 160 kilograms. Despite their sharp teeth, they are generally not aggressive towards humans. These sharks prefer coastal sandy bottoms up to 20 meters deep, where they hunt rays, other sharks, moray eels, or squid.
The Basking Shark (Cetorhinus maximus) is the second-largest living shark globally, reaching over 10 meters in length. This filter feeder is identified by its wide, open mouth and gill rakers used to capture zooplankton. Despite its immense size, the basking shark is harmless to humans, as its diet consists solely of tiny organisms. It is a migratory species found in temperate oceans, including the Mediterranean.
Ecological Role and Habitat Dynamics
The Mediterranean Sea’s characteristics make it a suitable habitat for a variety of shark species. Its connection to the Atlantic Ocean via the Strait of Gibraltar provides a migratory pathway for many pelagic sharks. The sea’s diverse depths, ranging from shallow coastal areas to over 15,000 feet in some basins, cater to different shark preferences. This range includes coastal habitats, open ocean waters, and deep-sea environments.
Sharks serve as apex predators within the Mediterranean marine ecosystem. They regulate prey populations, contributing to the overall health and balance of the food web. Their presence helps maintain species diversity, preventing any single prey species from becoming overly dominant. Different shark species occupy specific niches. Some prefer shallow, sandy bottoms, while others thrive in open, deeper waters.
The Mediterranean’s warm waters and abundant sea creatures provide a consistent food supply for sharks. This influences the distribution and seasonal movements of shark species across the basin. Sharks are vital to the marine environment, and their decline could lead to broader ecological consequences.
Conservation Status and Threats
Shark populations in the Mediterranean Sea face significant threats. Over half of the shark and ray species in the region are considered threatened with extinction, making the Mediterranean one of the most concerning areas globally for these animals. This situation has worsened over the last decade.
Overfishing is a major threat, including both targeted fishing and bycatch. Many sharks are vulnerable to overexploitation due to their biological characteristics, such as slow growth rates, late maturity, and producing few offspring after long gestation periods. This makes their populations slow to recover once depleted. For instance, the critically endangered Blue Shark and Porbeagle are often caught for their meat, which can sometimes be mislabeled as swordfish in markets.
Habitat degradation and pollution also contribute to the decline of shark populations. This includes damage from shipping, underwater construction, contamination, and plastic waste.
Conservation measures have been identified across the 22 coastal states of the Mediterranean. These include bans on finning, regulations to reduce bycatch, and prohibitions on catching certain protected species. However, enforcement often falls short, particularly in non-European Union countries. Ongoing projects aim to improve data collection, promote responsible fishing practices, and raise public awareness.