Ecology
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Coelacanths are generally considered to be deep-water fish and live in water that is up to 700 meters deep. They generally dwell in caves, which is why their coloration is thought to be the way it is. They have white spots on their scales that help camouflage the fish in dark caves covered in sponges and oysters. Most coelacanths stay in caves around 100 to 500 meters underwater while the sun is out because they have sensitivity to light, but they swim as shallow as 50 meters at night when it is dark. It is believed that dim light is and the temperature of the water is more important than how deep they live at. Ideal water conditions have a temperature of around 14 to 20 degrees Celsius. This temperature is important because it controls how much oxygen they can absorb through their gills from water. Islands create ideal habitats for coelacanths because of the abundance of caves, crevices and coves for the fish to live in.
Coelacanths are primarily active at night for several reasons. The most important reason is that their eyes are adapted to low light levels, so sunlight is harmful for them. Another reason for night activity is that they do not encounter as much resistance from currents that generally run stronger during the day due to factors such as wind. This slows down their metabolism and creates the need for less energy than if they were on the move.
The primary geographic distribution of coelacanths is around the coast eastern Africa. They have been known exist off the coasts of Comoros, Tanzania, Mozambique, Indonesia, Madagascar, Kenya, and South Africa. The island chain of Comoros in the Indian Ocean is the most common place to find coelacanths, almost entirely of the Latimeria chalumnae species. The primary reasons for this distribution are that food is abundant in these areas and the water temperature is ideal.
Coelacanths are known to have a wide range of food in their diet. They are often regarded as “opportunistic feeders,” which means they will eat whatever they encounter. This also means that they do not have a preference for one type of prey in particular. Coelacanths are thought to search for prey through the use of the rostral organ in the front of their skull. This organ is believed to receive the electric fields off other fish. The diet of the coelacanth is known to be often compromised of lantern fish, stout beard fish, cardinal fish, cuttle fish, squids, witch eels, snipe eels, swell sharks, and other deep reef habitat fish. An aspect of the diet of this fish thought to contribute to it longevity as a species is its ability to slow down its metabolism by a form of hibernation where it sinks into deep depths. They primarily feed at night and studies have shown that they often time leave their caves at the same time right before dark to hunt for food.
Coelacanths are known to interact somewhat peacefully with each other. They seem content and calm while in close proximity of each other, especially in small caves. They seem to dislike direct contact with one another and immediately move away if they touch. Coelacanths often react with a panic flight when anything unusual or a potential predator draws near. The predators of coelacanths are not well known, but bite marks from sharks have been seen on coelacanths.
The coelacanth also has a unique type of movement. They often utilize the current to drift around and use their paired fins to guide themselves and control where they move. The high number of fins that are unique to the coelacanth allow it to maneuver very quickly and precisely. This type of movement allows this fish to move in almost every direction, which is very helpful in a cave habitat. The rostral organ is also thought to give the coelacanth “electroperception,” allowing them to sense objects or obstacles in their way.
In terms of reproduction, Coelacanths are ovoviviparous. This means that the females keep their eggs inside of their body, allowing the embryos to develop, with a year long gestation period. Once the embryos hatch, the mother gives a sort of live birth to pups that can survive on their own.
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The primary geographic distribution of coelacanths is around the coast eastern Africa. They have been known exist off the coasts of Comoros, Tanzania, Mozambique, Indonesia, Madagascar, Kenya, and South Africa. The island chain of Comoros in the Indian Ocean is the most common place to find coelacanths, almost entirely of the Latimeria chalumnae species. The primary reasons for this distribution are that food is abundant in these areas and the water temperature is ideal.