The Angel Shark, Also Known as the Sand Devil, Conceals Itself on the Seabed

Essential Insights

Could the angel shark be considered the most sacred fish in the ocean? Its name suggests a divine and serene nature, and many seafood enthusiasts describe its flavor as a heavenly delight.

Or is their name derived from the fact that it's astonishing they are even categorized as sharks?

Unlike the stereotypical shark with its streamlined, torpedo-like body and menacing fins, the angel shark appears as though it has been flattened, giving it a unique and unusual appearance.

Angel Sharks vs. Skates, Rays and Other Sharks

The angel shark bears a closer resemblance to a skate or ray, the shark's bottom-dwelling relatives, but it is scientifically classified as a shark within the Squatinidae family, which includes only one genus: Squatina.

The term Squatina, derived from Latin, means "a type of shark," possibly indicating early uncertainty about its classification. However, the name fits well, as these sharks are robust and more compact compared to other shark species.

What about their alternate name, angel shark? The 24 species of Squatina owe this name to their unique appearance. The extensions around their head are actually flattened pectoral fins, giving them the appearance of a winged or haloed shark, reminiscent of a celestial being.

While their flattened pectoral fins inspire their angelic name, they also play a crucial role in their classification as sharks. Unlike skates and rays, whose pectoral fins are fused to their heads, angel sharks' fins remain separate, a key distinction.

Though this distinction may seem minor, it is significant enough to keep them classified within the shark family.

These flattened fins enable them to spend extended periods resting on the ocean floor, lying in wait for prey. Despite their less intimidating appearance compared to other sharks, they are formidable predators. Their sharp teeth and powerful bite have earned them a contrasting nickname: sand devil.

Angel Shark Anatomy

As noted earlier, angel sharks truly embody their "squatty" name, with most Squatina species reaching only around 5 feet (1.5 meters) in length. Some species, like the Japanese angel shark (Squatina japonica), can grow up to 6.5 feet (2 meters), but this is their maximum size.

Most angel sharks weigh approximately 60 pounds (27 kilograms).

Fins

Angel sharks resemble rays more than great whites, but they possess all the fundamental features of sharks. These features, however, are flattened dorsoventrally, or from top to bottom. The most noticeable characteristic is the broad pectoral fins, which inspire their angelic name.

To clarify, these fins are not connected to the head, unlike those of rays. The pelvic fins are also flattened and extend outward from the body.

Mouth

The mouth is positioned at the front of the snout and contains intimidating teeth. These triangular teeth are razor-sharp and taper to needle-like points.

Flanking the mouth are barbels, whisker-like sensory organs that detect the chemical signals of prey along the seabed.

Gills

Positioned along the sides of the head are gill slits, enabling the angel shark to breathe. The location of these slits is a key difference from rays and skates, which have gill slits on the underside of their heads.

Unlike many sharks that require constant movement to force water over their gills, the angel shark uses muscular action to draw water over its gill slits while stationary. Additionally, it possesses a spiracle, a tube behind the eyes that allows water intake when the mouth is closed.

Tail

Angel sharks stand apart from other sharks in the structure of their caudal fin, or tail. While most sharks have tails with a larger upper lobe, angel sharks exhibit the opposite trait.

Their lower lobe is more elongated, which likely aids in swift upward propulsion when ambushing prey from below.

A Body Designed for the Seabed

An effective ambush from below is crucial for the angel shark's survival. Its flattened body, sensory barbels, and tail adapted for rapid upward movement are all evolutionary features that enable it to thrive on the ocean floor, lying in wait for unsuspecting prey.

Their coloration also provides excellent camouflage. Angel sharks display shades of white, gray, brown, and black, blending seamlessly with the seabed. Some even have red spots, further enhancing their ability to blend into their surroundings.

Angel Shark Habitat and Hunting

Angel sharks inhabit various regions across the globe, including both the Atlantic and Pacific Oceans' eastern and western coasts. They are rarely found in the Indian Ocean, with the exception of a small southwestern area.

Among all angel shark species, the Pacific angel shark (Squatina californica) is the most extensively researched and recognized, though many species share similar traits aside from their geographic distribution.

Despite inhabiting diverse regions worldwide, from cool to tropical waters, angel sharks consistently seek out similar ocean environments. They reside on the ocean floor, in both shallow zones and depths reaching up to 4,265 feet (1,300 meters).

The Hunting Strategy of Angel Sharks

Angel sharks conceal themselves in the sand and mud of the seabed, with only their eyes visible. They can remain motionless for days, patiently waiting for the ideal prey to pass by.

When attacking prey — typically bony fish like flounder and halibut, crustaceans, or mollusks — the shark swiftly lifts its front half to ambush from below. It can seize its prey in as little as a tenth of a second.

Angel sharks often favor specific hunting locations, but if local fish detect their presence, the shark will temporarily relocate several miles away.

Although their barbels are always active, the most critical sense for a hunting angel shark is its vision.

In a 1999 study, Pacific angel sharks were shown rubber fish lacking any olfactory, electrical, or vibratory cues typical of real fish. The sharks attacked nearly all the targets.

When threatened, angel sharks may bite humans with their sharp teeth, but generally, humans pose a far greater threat to them than they do to us.

Angel Shark Species

There are 24 species of angel sharks inhabiting the global ocean.

Angel Shark Fishing and Recovery

Out of the 24 angel shark species, eight are classified as critically endangered by the International Union for Conservation of Nature (IUCN), with an additional four listed as endangered.

Fishing, both targeted and accidental, poses the greatest danger to angel sharks. These seabed dwellers are often caught in nets intended for other species. Additionally, habitat destruction caused by pollution and coastal development further endangers their survival.

Angel shark populations are highly susceptible to overfishing due to their slow growth and low reproduction rates. They typically give birth to litters ranging from six to 25 pups. The gestation period varies by species but usually lasts between eight and 10 months.

Angel sharks are ovoviviparous, meaning the females carry eggs that hatch internally, resulting in live births. Newborn pups measure around 9 inches (23 centimeters) and are born in deeper waters, where adults seek to protect them.

The Tale of the Pacific Angel Shark

Before the 1970s, Pacific angel sharks were considered "junk fish," often discarded when caught accidentally. This changed when Michael Wagner, a seafood processor in Santa Barbara, California, highlighted their culinary appeal.

Wagner's efforts were largely responsible for introducing the Pacific angel shark to countless dining tables.

As reported by the Monterrey Bay Aquarium, Pacific angel shark catches surged from 366 pounds (166 kilograms) in 1977 to 700,000 pounds (317,545 kilograms) by 1984. At its peak in 1985 and 1986, around 1.2 million pounds (544,311 kilograms) were caught annually.

The implementation of a minimum size limit in 1989 and an inshore gill net ban in 1994 aided the recovery of the Pacific angel shark population, though other species still require conservation efforts.