Fish
Lumpfish
Cyclopterus lumpus · also called lumpsucker, henfish
The lumpfish looks like a mistake — a fat, warty, almost round fish with tiny fins and a sucker stuck on its belly, drifting slowly through the cold North Atlantic. Yet its eggs turn up on canapes as budget caviar, and millions of farmed lumpfish now work as living lice-pickers in the world’s salmon cages.
Overview
Cyclopterus lumpus is a rotund, knobbly fish of the cold North Atlantic, blue-grey in the female and reddish in the breeding male, with rows of bony tubercles instead of normal scales and a sucker disc on the underside formed from the fused pelvic fins. It is a weak swimmer that clamps itself to rocks and weed, and it eats slow prey — jellyfish, comb jellies, small crustaceans, and fish eggs.
A devoted father
Females lay a large mass of pink-orange eggs in shallow water, and the male stands guard for weeks, fanning them and fending off crabs and fish, sometimes left high and dry by the falling tide.
Roe and lice
The roe of egg-bearing females is washed, salted, and dyed black or red and sold as a cheap caviar substitute, mainly from Iceland, Greenland, Norway, and Canada. Separately, farmed lumpfish are now placed in salmon sea cages to pick off parasitic sea lice, reducing the need for chemical treatments, though their welfare in the cages is debated.
Status
The lumpfish is Near Threatened, moved up from Least Concern in 2020 because the fishery for its roe targets breeding females at spawning time, and bycatch and signs of decline add to the concern.
Lumpfish: common questions
Why does a lumpfish have a sucker?
The sucker lets a slow, weak-swimming fish hold its position where it wants to be without wasting energy. Formed from the fused pelvic fins into a round disc on the underside of the body, it works like the suction pad of a climbing toy, and a lumpfish uses it to fix itself to a rock, a stone, or a frond of kelp in areas of current, swell, or surf that would otherwise sweep it away. It is especially important during the breeding season, when the male has to stay put beside the egg mass in shallow, wave-battered water for weeks, and it also lets juvenile lumpfish attach to drifting seaweed and be carried along.
Is lumpfish caviar real caviar?
Strictly, no. The term caviar properly refers to the salted roe of sturgeon, and the eggs of any other fish are, by the stricter definitions, roe or a caviar substitute rather than caviar. Lumpfish roe is one of the most common substitutes, harvested from egg-carrying females, then rinsed, salted, and coloured with a dye, usually to a glossy black but sometimes red or orange, because the natural roe is a dull pinkish colour. It has a firm pop and a briny taste, is far cheaper than sturgeon caviar, and is widely used as a garnish. The dye can bleed onto other foods, which is why lumpfish roe is often served slightly apart on a plate.
How are lumpfish used in salmon farming?
Atlantic salmon reared in sea cages are plagued by sea lice, small parasitic crustaceans that attach to the skin and can weaken or kill fish and spread to wild salmon and sea trout nearby. Rather than relying only on chemical or mechanical delousing, many farms now stock their cages with cleaner fish, and the lumpfish is the main cold-water choice, with wrasse used in warmer conditions. The lumpfish swim among the salmon and pick lice off them. This reduces chemical use, but the practice has drawbacks, since large numbers of lumpfish are needed, many die in the cages, and their own welfare and the sustainability of supplying them, whether farmed or wild-caught for broodstock, are under scrutiny.
Why is the lumpfish considered Near Threatened now?
The change, made by the IUCN in 2020, reflects concern about the fishery for its roe. That fishery specifically targets mature females carrying eggs as they move inshore to spawn, which removes breeding animals at the most sensitive point in their life cycle, and catches in the main fishing nations have at times been high relative to the estimated stock. Lumpfish are also taken as bycatch in nets set for other species. Combined with a fairly slow life history and signs of decline in several areas, this was enough to lift the species from Least Concern to Near Threatened, with calls for tighter catch limits and better monitoring.