Angelshark

The angel shark is a unique marine predator belonging to the genus Squatina. They are the only living members of the family Squatinidae and the order Squatiniformes. While they are technically sharks, their physical appearance is very different from typical shark species. They possess highly flattened bodies and broad pectoral fins. This shape makes them look much more like rays than most other sharks. They inhabit various temperate and tropical seas across the entire world. Most species prefer shallow waters, but some live in deeper areas down to 300 feet.

Angel sharks are specialized ambush predators that rely on camouflage to survive. They spend much of their time resting on muddy or sandy benthic substrata. To hunt, they bury themselves in loose sediment and remain motionless for weeks. When a target swims nearby, the shark uses extensible jaws to snap upward rapidly. They also use negative pressure to suck prey into their mouths. Their diet consists of fish, crustaceans, and various mollusks. This hunting method requires them to stay very still to avoid detection.

These sharks have a unique respiratory system compared to other bottom-dwelling fish. Most fish pump water through an oropharyngeal cavity to breathe. Angel sharks do not use this method. Instead, they use gill flaps located underneath their bodies to pump water. This specialized mechanism allows them to breathe while remaining discreetly buried. By using these flaps, they avoid creating movements that might alert prey. This biological adaptation is essential for their stationary, bottom-dwelling lifestyle.

The evolutionary history of the Squatiniformes is quite ancient. The earliest members of this group appeared during the Late Jurassic period. This was approximately 160 million years ago in Europe. These early sharks belonged to the genus Pseudorhina. Preserved full-body fossils of Pseudorhina show they were very similar to modern Squatina species. Some modern records of the genus date back to the Early Cretaceous in England. This long history shows how successful their body plan has been over millions of years.

There is significant diversity among the recognized species within this genus. There are currently 26 recognized species of angel sharks. For example, the Japanese angel shark is quite large and can reach 2 meters in length. Most other species typically grow to about 1.5 meters. In the southern western Atlantic, three specific species exist: Squatina guggenheim, S. occulta, and the Brazilian guitarfish, Pseudobatos horkelii. These species are currently listed as threatened and are protected under Brazilian law.

Human activity has caused dramatic changes in angel shark populations. In the mid-1980s, landings of the Pacific angel shark rose significantly. In 1986, they reached over 1,125 tonnes off the US West coast. Before the late 1980s, they were often considered "junk fish" used only for crab bait. However, a market was developed in 1977 by Michael Wagner in California. This led to a massive increase in catches. By 1985, the annual take in central California exceeded 454 tonnes, involving roughly 90,000 sharks.

Today, many angel shark species face a high risk of extinction. The Squatina squatina species was classified as "Critically Endangered" by the IUCN in 2010. They are highly sensitive to bottom trawling and accidental capture in gillnets. Because they live close to the shore, bycatch rates are very high. In 2008, the UK government gave the angel shark full protection. Conservation groups like the Angel Shark Conservation Network are now working with authorities in Greece and Turkey. They aim to create strategies to protect these remaining populations from disappearing.