Echeneidae
The Echeneidae, commonly known as remoras or suckerfish, are a family of perciform fish that are characterized by their distinctive dorsal fin, which has been modified into an oval-shaped adhesive disc. This disc, located on top of the head, allows remoras to attach themselves to larger marine animals, such as sharks, rays, turtles, whales, and even boats, for transportation and access to food. Remoras are found in tropical and subtropical waters worldwide, and their unique biology has captivated scientists and marine enthusiasts alike.
Characteristics
Remoras typically range in size from 10 to 100 centimeters (4 to 40 inches), with the largest species, the shark sucker (Echeneis naucrates), reaching up to 2 meters (6.5 feet) in length. Their bodies are elongated and somewhat flattened, with a streamlined shape that aids in swimming. Their color can vary from brown to grayish-blue, often with dark spots or stripes. Remoras have a single dorsal fin that is modified into an adhesive disc, which is composed of numerous lamellae (thin, plate-like structures) covered in mucus. This disc allows the remora to attach firmly to its host, even in strong currents. They also possess a long, whip-like tail, which provides them with good maneuverability.
Environment
Remoras are found in a wide range of marine habitats, including open ocean, reefs, estuaries, and coastal waters. They are typically found in tropical and subtropical regions, but some species have been observed in temperate waters as well. Remoras are generally considered to be pelagic fish, meaning they live in the open ocean, but they can also be found in shallower waters near the coast. They are often associated with larger marine animals, which they use as a means of transportation and food acquisition.
Diet
Remoras are primarily scavengers, feeding on scraps of food that fall from their hosts, as well as parasites and other small organisms that live on the host's skin. They have also been observed feeding on the host's feces. Some remoras have been known to steal food from other fish, and some species may even eat the eggs of other fish. Their diet is opportunistic and varies depending on the availability of food sources.
Symbiosis
The relationship between remoras and their hosts is an example of commensalism, a type of symbiotic relationship where one species benefits while the other is neither harmed nor helped. The remoras benefit from their association with larger animals by gaining transportation, access to food, and protection from predators. The host animals are generally unaffected by the presence of remoras, although there have been some reports of remoras interfering with the feeding behavior of their hosts.