Facts: The Chimaera (Ghost Shark)

Chimeras are large-eyed cartilaginous fish that primarily inhabit the deep ocean. There are around 40 different species. Many of these species were just discovered within the last 15 years. Chimeras are relatively abundant and can be found in all oceans around the world, most commonly from 650 to 6500 ft deep. They use their long fins on their sides, called pectoral fins, to slowly swim over the seafloor. They primarily feed on organisms inhabiting sandy seafloors, such as clams and crabs. However, they will also feed on a variety of other creatures, including other chimeras. Instead of sharp teeth, chimeras have large grinding tooth plates for crushing prey. They have been observed diving headfirst into the sand, probably searching for prey. Chimeras use smell and electroreception to find their prey. The visible lines on their head assist them in sensing vibrations in the water. For defense, they possess a long spine in front of their dorsal fin. Males possess an additional retractable appendage on their forehead used to grasp onto females during mating. Some female species have been shown to store sperm after mating, possibly for years, most likely due to the fact that it can be hard to find a mate in the deep ocean. All chimeras are oviparous. This means that instead of giving live birth, they lay egg cases. Each egg case contains one embryo. It has been observed in some species, such as the spotted ratfish, that the female will lay two egg cases at a time and multiple sets of egg cases throughout the year. The egg cases fall to the bottom, where they incubate for about a year, before hatching. Hatchlings resemble miniature adults. Depending on the species, adult chimeras can grow over 4 ft long. They possess smooth skin and no scales. The many predators of chimeras include larger fish like sharks. Most chimeras are restricted to inhabiting deep waters. The few species of chimera that can inhabit shallow waters, such as the spotted ratfish, are sometimes accidentally caught by bottom trawling fishing vessels. Even though chimeras are sometimes called ghost sharks, they are not actually sharks. It is thought that chimeras diverged from sharks around 400 million years ago. For more marine facts, click the SUBSCRIBE button!!