Lumpfish

What it is

This species belongs to the family Cyclopteridae and is the sole member of its genus. Adults possess a spherical body covered in knobbly skin and bony tubercles. Their pelvic fins have evolved into a powerful suction disc that allows them to cling firmly to rocks or other surfaces. Males are generally smaller than females, with the largest recorded specimen reaching 61 cm in length and weighing nearly 10 kg. Colouration varies widely, including shades of blue, grey, olive, yellow, and brown, while mature males develop an orange-red hue during the breeding season.

Where it lives

Lumpfish inhabit the North Atlantic Ocean and adjacent Arctic regions. Their distribution extends south to Chesapeake Bay on the American coast and Spain on the European coast. They are occasionally reported in the Mediterranean Sea. Juveniles typically occupy warmer waters between 6 and 9 °C, whereas adults prefer temperatures between 4 and 8 °C. They become rare in waters exceeding 12 °C. While often associated with the seabed, they also spend time in open water, migrating vertically through the water column.

How it lives

After hatching, young fish live in tidal pools or among floating seaweed before moving to open ocean waters. In the pelagic zone, they feed on gelatinous zooplankton, small crustaceans, and fish eggs. Juveniles exhibit biofluorescence, emitting green light from specific body ridges. Adults alter their daily behaviour, spending more time near the surface at night and closer to the seabed during the day. They lack a swim bladder but can move rapidly between depths of over 300 metres.

Breeding and life cycle

Mature fish migrate to coastal areas in spring to spawn. Females lay eggs in batches of 50,000 to 220,000 onto rocky nests selected by males. The male guards the eggs for approximately one month, fanning them with his fins to ensure oxygen flow. Females often return to the same spawning grounds and times each year. The ovaries of mature females can constitute up to one-third of their total body weight prior to spawning.

Fish and people

The primary commercial value lies in the roe, which is processed into inexpensive caviar substitutes. Major catches occur in Iceland and Greenland, where females are targeted using gillnets. Male fish are sometimes caught for local consumption in Scandinavia, prepared by salting, smoking, or boiling. Additionally, live lumpfish are used as cleaner fish on salmon farms in several countries to reduce parasite loads. Bycatch issues have impacted fishing certifications in some regions.

Status and threats

Populations in Iceland and Norway are monitored and considered healthy. Greenland shows stable trends based on limited data. The Canadian population is classified as threatened due to severe declines. Abundance in the North Sea and Baltic Sea remains unknown due to insufficient survey data. Fisheries in Iceland, Norway, and Greenland have held Marine Stewardship Council certifications, though Iceland’s was temporarily suspended due to bycatch concerns before being reinstated.

Relatives and look-alikes

The genus Cyclopterus contains only this single species. Other members of the family Cyclopteridae include various lumpsuckers, though taxonomic authorities differ on whether to recognize subfamilies within the group. Lumpfish are distinct from other bottom-dwelling fish due to their pelagic juvenile phase and unique suction disc adaptation.

Questions people ask about Lumpfish

Good reading and sources

• Cyclopterus on WikipediaEncyclopedia
• More photos on Wikimedia CommonsPhotos
• Wikidata recordOpen data