Hidden Gems: Shifty Sharks

Most guests easily spot the grey silhouettes of sand tiger and sandbar sharks in Shark Alley, but they aren't the only sharks in Aquarium habitats. Only six of the ten shark species found at the National Aquarium are routinely seen by visitors, which makes the other four a fun challenge to find.

A Reef Masquerade

Blacktip Reef teems with life as diamondfish flit through the bright, shallow waters and red hind grouper peer out from their shadowy coral caves. Two other species lurk within these waters and are masters of camouflage, easily disappearing into the exhibit's backdrop.

The ornate and tasselled wobbegongs look less like sharks and more like coral and rock, at least from the front. Their heads are marked with splotches and branching protrusions that resemble a beard, especially in the tasselled's case. Without similar camouflage on their tails, they wedge themselves into darker crevices from which they would ambush prey if our dive staff weren't already feeding them. Their preference for dark caverns means you'll have the most luck finding them from Blacktip Reef's underwater viewing area, looking through the two darkest windows on the left.

Cloaked Among Kelp

A few stories up from Blacktip Reef, artificial algae fronds sway in the chilly waters of the Kelp Forest located within North Atlantic to the Pacific. Brilliant orange garibaldis slowly swim between the rocks, passing vermilion rockfish and short-spined sea stars. Like the wobbegongs, the two elusive shark species in Kelp Forest are sedentary and tend to lurk.

The horn shark and swell shark are mottled brown and blend in with the rocks they rest on or under. They are not graceful swimmers and have little need for speed since they eat scuttling crustaceans, slow sea urchins and immobile mussels in the ocean. Given their slower speeds and smaller sizes, both species have adaptations to help defend themselves from predators. The horn shark is equipped with two venomous spines in front of its dorsal fins, while the swell shark can take in enough water to expand to three times its normal girth—a handy way to wedge its body into a cave or crevice and resist being pulled out. Guests should look near the exhibit's rock shelves or inside small caverns to spot the tails of one or both species.

Helping These and Other Sharks

The wobbegongs' affinity for reefs protects them from larger-scale fishing pressures. For example, the tasselled's range overlaps with many no-take areas of the Great Barrier Reef. This means most wobbegong species are considered of "least concern" by the International Union for Conservation of Nature. Rising sea levels, increased water temperatures and ocean acidification put these coral reef homes at risk, though. Using renewable energy or taking greener transportation are some ways to slow these environmental impacts and keep wobbegongs' habitats intact.

Like the wobbegongs, the horn and swell sharks aren't sought after by fisheries. They are sometimes caught as bycatch in crab traps or trawls, though. This can harm their populations because it takes both species several years to mature, and they don't have many offspring. Many sharks share these traits, so cleaning up fishing gear or trash from shorelines and pushing for responsible fisheries management are a few ways to protect them.