What is a Lumpsucker Fish?
The lumpsucker fish is a small fish recognised for its distinctive rounded appearance and behaviour. It belongs to the Cyclopteridae family, which is part of the order Scorpaeniformes. Scorpaeniformes includes a diverse group of mostly marine fish, including scorpionfishes, sculpins, and dragonfishes known for having lateral rows of larger bony thorns along their body. Whilst most lumpsuckers are generally 5-30 centimetres in length, some have been known to grow up to 50 cm.
The lumpsucker’s name comes from its lumpy body and the suction disc on its underside, which it uses to cling to rocks, seaweed and other surfaces. Despite their unconventional look, lumpsuckers are well-adapted to their environment and have evolved to thrive in challenging environments.
Where Can You Find Lumpsucker Fish?
Lumpsuckers are commonly found in the cold, coastal waters of the North Atlantic and Pacific Oceans. In the North Atlantic, they have been recorded along the coasts of Europe, including Iceland, Norway, parts of France, and the UK.
They have occasionally been spotted around Cornwall, particularly in areas with kelp forests and rocky habitats. The most commonly found species in Cornwall is the European lumpsucker (Cyclopterus lumpus).
Lumpsuckers typically inhabit depths ranging from shallow coastal zones to deep waters and have also been observed off the coasts of Canada and the northeastern United States. In the North Pacific, lumpsuckers are found in the cold waters of the Bering Sea and Alaska, as well as along the Pacific coasts of Russia and Japan.
The Biological Reasons for that Distinctive Shape
One of the most distinctive features of the lumpsucker is the suction disc on its underside, which allows it to attach firmly to surfaces. This disc is formed by modifications of the pelvic fins, which have fused together to create a powerful suction mechanism. This adaptation is essential for surviving in strong currents, as it helps prevent the lumpsucker from being swept away.
The lumpsucker’s round, stocky body helps it to conserve energy while it is anchored to surfaces. The compact shape minimises water resistance, making it easier for the fish to stay still. This round shape also reduces the fish’s surface area, helping it to conserve heat in colder waters and making it less visible to predators.
Evolution of the Lumpsucker
The lumpsucker has a relatively low swimming ability due to its short, rounded body and reduced tail fin. To counteract this, it has adapted to be more of a bottom-dwelling fish, rather than a free-swimmer. Its body structure helps it maintain its position on the seabed, which also aids in feeding on seafloor organisms.
The lumpsucker’s shape is an evolutionary adaptation that enables it to survive in challenging environments. Its rounded body, suction disc, and lumpy texture all help it to remain stationary in strong currents, hide from predators, and secure food. Its form is a perfect example of how a fish’s physical characteristics are shaped by its ecological niche and survival needs.
Lumpsucker Appearance
Lumpsuckers have a rough appearance, often covered in small bumps or tubercles. This texture helps to blend them into rocky or weedy environments, providing camouflage and protection from predators. The bony armour also acts as a form of protection against abrasions in turbulent waters. The lumpsucker fish has thick, mucus-covered skin that helps protect it from parasites, infections, and physical damage. This slippery coating also makes it difficult for predators to grab onto the fish.
The European lumpsucker is slate grey to blue, although the colouring in the males changes to blue dorsally and red/orange ventrally during the breeding season.
Lumpsucker Behaviour
Between February and May, female lumpsucker fish migrate to shallower waters to lay their eggs and wait for their eggs to hatch. The newly hatched fish are 6-7 millimetres in length, and have a ‘tadpole-like’ form. Eggs of the lumpsucker are also commercially harvested as a form of caviar.
Lumpsuckers become more social during the breeding season. During this time, males may become more territorial, as they guard the eggs for 6-7 weeks, defending their eggs from other males. While males may interact with each other during this period (often with aggressive displays), outside of mating activities, lumpsuckers are generally non-social and avoid unnecessary contact with other fish.
Communication Methods
Lumpsucker fish are generally not highly communicative, however, they do have some subtle forms of communication relating to mating behaviour or territorial behavior.
Lumpsuckers will use visual signals such as colouration and body posture to communicate during the breeding season. Males can display changes in colouration or postures that signal readiness for mating or territorial defence. Bright colours can also serve as a way to intimidate rivals during breeding contests.
Lumpsuckers may use pheromones (chemical signals) to communicate, especially during mating. These chemicals are released into the water to signal the presence of a mate or to establish dominance.
Females may also release specific pheromones to signal their readiness to spawn. Male lumpsuckers may use aggressive posturing or swimming patterns to warn off rival mates from their nesting area. These behaviours are non-verbal and rely on physical presence or subtle movements to convey dominance.
Preferred Prey
Despite their tough, bony armour, lumpsucker fish can still fall prey to a variety of marine predators.
Predatory fish are a threat to lumpsuckers, species that are large enough to overpower the lumpsucker’s defences and that share the same habitat. These could include: cod, pollack, flatfish, or seabass.
Seabirds that dive or fish in coastal waters may also prey on lumpsuckers, especially when they are young or juvenile fish. Birds like gulls or cormorants might catch and consume lumpsuckers while they are near the surface or at shallow depths.
Larger marine mammal species such as seals might also target lumpsuckers, particularly when hunting in cold, rocky coastal waters.
Primary Food Sources
Lumpsuckers are bottom-dwelling carnivores that feed on a variety of small organisms found in their habitat. Lumpsuckers’ diet mainly consists of small invertebrates that are abundant in coastal environments such as crustaceans, molluscs, and worms.
Lumpsuckers also eat zooplankton, which include tiny organisms that drift in the water. Lumpsuckers are sit-and-wait predators. Their feeding strategy is based on opportunistic predation, meaning they take advantage of whatever small invertebrates or plankton are available in their immediate environment. As they remain stationary, they will snap at passing food with their small, pointed mouths, feeding on whatever comes close enough to their territory.
Are Lumpsucker Fish Dangerous?
Lumpsucker fish are not dangerous to humans. They are small, relatively passive fish that pose no threat to humans in terms of aggression or venom.
Lumpsuckers do not possess any venom or poison to defend themselves. If you encounter a lumpsucker while diving or exploring the ocean, they will typically remain in their place and not react to humans unless disturbed.
Human Uses
Lumpsucker fish are not widely targeted for human consumption, but they do have certain uses.
Lumpsucker roe (eggs) is considered a delicacy in some parts of the world, particularly Russia, Japan, and Iceland. The eggs are often harvested, salted, and sold as a type of caviar. Lumpsucker caviar is prized for its distinctive flavour, and is considered more affordable than traditional sturgeon caviar, but is still highly valued for its texture and taste.
Lumpsucker fish are sometimes used in scientific research to study fish behaviour, marine ecology, and adaptations to cold-water environments. Their unique physical characteristics make them interesting subjects for studies on evolution, adaptations, and habitat use.
Lumpsuckers are occasionally kept in aquariums due to their distinctive appearance. However, because they require specific habitat conditions, they are not as commonly found in the aquarium trade as other species.
Threats to Lumpsuckers
Lumpsucker fish face several threats that can impact their survival, particularly due to their specific habitat requirements and ecological characteristics. These threats mainly stem from human activity and climate change. As human activity increases along coastlines, habitat destruction is a major concern for lumpsuckers. Construction of ports, piers and other infrastructure can damage or destroy the kelp forests, rocky shores, and shallow coastal areas that lumpsuckers rely on for shelter and feeding.
Pollution events including oil spills, chemical runoff, and plastic waste can also degrade the water quality in which lumpsuckers live. These pollutants can harm their habitat, impact their prey availability and introduce toxic substances into their environment.
Rising sea temperatures due to climate change can alter the distribution of cold-water species like lumpsuckers. As water warms, lumpsuckers may be forced to migrate to cooler waters, which could limit their available habitat and ability to thrive.
Overfishing of certain marine species can affect the availability of prey for lumpsuckers. While lumpsuckers themselves are not typically targeted by fisheries, bycatch of lumpsuckers in fishing nets could lead to declines in their populations. Trawling and other destructive fishing practices can also affect lumpsucker habitats, further threatening their survival.
Conservation Status of Lumpsuckers
The conservation status of lumpsucker fish varies by species. The European lumpsucker was listed as “Near Threatened” by the IUCN in 2013. While this species is not currently listed as endangered, factors including habitat loss, pollution, and overfishing could threaten their populations in the future, should conditions continue to deteriorate.
FAQs
Q: What do lumpsucker fish look like?
A: Lumpsuckers have a round, bumpy body with a distinctive suction disc on their underside. Their body is often a dull green/brown/grey with spots or patterns that help them to camouflage into their surroundings.
Q: Why do lumpsucker fish have a suction disc?
A: The suction disc on a lumpsucker’s underside helps it to cling on to substrates in strong currents. This allows the fish to stay stationary and avoid being swept away.
Q: What do lumpsucker fish eat?
A: Lumpsuckers are opportunistic feeders that primarily eat small invertebrates, such as crustaceans, zooplankton, and worms.
Q: Are lumpsucker fish dangerous to humans?
A: No, lumpsuckers are not dangerous to humans. They are small, passive animals that do not pose any threat.
