AT A GLANCE
- Common Name: Common Remora
- Scientific Name: Remora remora
- Category: Fish
- Subcategory: Bony Fishes
- Range: Cosmopolitan in warm-temperate and tropical oceans worldwide, throughout the Atlantic, Pacific, and Indian Oceans, and the Mediterranean Sea
- Habitat Type: Open pelagic oceanic waters and coastal reefs, almost exclusively attached to large marine hosts such as pelagic sharks, rays, sea turtles, marlins, and whales
- IUCN Red List Status: Least Concern
- Lifespan: 5 to 8 years
- Diet: Carnivorous/Commensal (parasitic copepods and isopods picked from the host’s skin, scraps of host meals, and pelagic zooplankton)
- Average Size/Weight: Length 30 to 60 cm (maximum up to 86 cm); weight 0.5 to 1.5 kg
- Key Defining Feature: Streamlined, dark slate-grey hitchhiking fish possessing a massive, oval laminated suction disc atop its flattened head that can clamp onto sharks with immense vacuum force
Overview
The Common Remora (Remora remora), celebrated since ancient antiquity as the legendary Sharksucker, is one of the most anatomically extraordinary symbiotic fishes in the world’s oceans. Belonging to the family Echeneidae, this pelagic traveler has evolved its first dorsal fin into an ingenious, mechanical suction pad on the crown of its head. Clamping securely onto the bellies and flanks of pelagic sharks, manta rays, and sea turtles, the Remora hitches free oceanic rides, keeping its host free of external parasites while dining on leftover crumbs.
Biology and Physical Characteristics
Remora remora has a sleek, torpedo-shaped, slightly flattened body covered in tiny cycloid scales. Its coloration is a uniform dark slate-grey, charcoal-brown, or blackish, blending with the underbellies of large ocean predators. Its defining evolutionary triumph is its cephalic suction disc, which occupies the entire flat top of the head and nape. Composed of 27 to 34 transverse lamellae (ridges) surrounded by a flexible fleshy rim, this structure is a radically transformed spinous dorsal fin. When the remora slides backward against a shark’s skin, the lamellae pivot erect, creating a powerful vacuum chamber that holds fast even against high-speed oceanic swimming.
Behavior and Ecology
The relationship between the Common Remora and its host is a classic marine mutualism. The remora gains effortless hydrodynamic transport, continuous water flow over its gills for respiration, and access to scrap food when its host attacks schools of prey. In return, the remora acts as a diligent oceanic cleaner, using its fine rows of teeth to pick off parasitic copepods, sea lice, and dead skin from the host’s body. If the host stops or feeds, the remora readily detaches with a slight forward slide to dart after food scraps before instantly reattaching. Ancient Greeks and Romans believed remoras possessed supernatural power to hold sailing ships motionless in the water, giving them the Latin name remora, meaning ‘delay’ or ‘hindrance.’
Conservation and Human Impact
The Common Remora is classified as Least Concern on the IUCN Red List. Due to its circumglobal distribution across all tropical and warm-temperate seas, its population is vast and secure. It is not commercially harvested for food, although it is occasionally caught incidentally by pelagic longline and tuna fisheries. Because it relies heavily on pelagic sharks and sea turtles, global declines in large shark populations can indirectly influence remora abundance.
Interesting Factoid
The suction disc on top of a Common Remora’s head creates such a powerful vacuum that ancient Caribbean fishermen tied ropes around remora tails and tossed them into the water to catch sea turtles, reeling in the turtle when the remora clamped onto its shell.