Ghost sharks, also known as chimaeras, are ancient cartilaginous fish. Though bearing “shark” in their name, they are distant relatives that diverged approximately 400 million years ago. They possess a unique appearance, characterized by large, reflective eyes, unusual head shapes, and often pale coloration. Their primary residence in the deep ocean, a largely unexplored realm, contributes to their mysterious and elusive nature.
Global Geographic Distribution
Ghost sharks are found across most of the world’s major oceans, excluding polar waters, including the Pacific, Atlantic, Indian, and Southern Oceans. Some species, like the Rabbitfish, have widespread distributions across areas such as the North Atlantic and Mediterranean. Others, such as the Galapagos Ghostshark, exhibit more limited ranges.
Different species often occupy distinct, sometimes overlapping, specific geographic regions. Many are sighted in deep waters near New Zealand and southern Australia. Over half of known species are found in the Indo-Pacific oceans, where new discoveries continue, such as around the Chatham Rise east of New Zealand’s South Island.
The Deep-Sea Environment
Ghost sharks primarily reside in the deep-sea environment, typically at depths ranging from 200 to 2,600 meters, though some have been recorded as deep as 3,000 meters. This profound depth explains why these creatures are rarely observed. The deep ocean represents a vast and largely unexplored region, covering over 70% of the Earth’s surface.
Conditions in these deep-sea habitats are extreme and consistently cold, often near freezing temperatures. This environment is also characterized by immense hydrostatic pressure and perpetual darkness, known as the aphotic zone, where sunlight cannot penetrate. Such challenging conditions have shaped the evolution of deep-sea inhabitants, allowing ghost sharks to thrive in a realm that offers refuge from many pressures faced by shallower-water marine life.
Specific Habitat Characteristics
Within the deep-sea environment, ghost sharks prefer specific seabed types, typically remaining within a few meters of the seafloor. They are often found on soft sediments, such as muddy or sandy bottoms, which they utilize for foraging and shelter. Some species also inhabit areas with rocky slopes, volcanic boulders, or cobbles.
Their lifestyle is primarily benthic. This relates to their diet, which largely consists of bottom-dwelling invertebrates like crabs, mollusks, octopuses, marine worms, and sea urchins. Ghost sharks possess sensory organs on their snouts that help them detect prey in the dark, allowing them to sense movement and weak electrical fields on the seafloor. They also frequent specific underwater features, including seamounts and continental slopes, which provide varied topography and potential food sources.