Cyclopterus

Monotypic genus of fish

Cyclopterus is a genus of marine ray finned fish belonging to the family Cyclopteridae, the lumpsuckers or lumpfish. Its only species is Cyclopterus lumpus, the lumpsucker or lumpfish.

Cyclopterus and C. lumpus were both first formally described in 1758 by Carl Linnaeus in the 10th edition of the Systema Naturae with the North and Baltic Seas given as its type localities. C. lumpus was the only species described by Linnaeus in the genus and is described in Catalog of Fishes as the "type by Linnaean tautonomy". however, other authorities place this taxon in the monotypic subfamily Cyclopterinae.

Cyclopterus is sexually dimorphic with females reaching larger sizes than the males. Males typically reach in length while females can typically grow up to in length and in weight. The largest specimen recorded measured in length, In the brackish water of the Baltic Sea, it usually does not surpass Mature males turn orange reddish during the breeding season. or in association with floating seaweed clumps. As they grow they migrate out into open water far from land where they live in the pelagic zone feeding upon gelatinous zooplankton, fish eggs and small crustaceans. When they reach maturity they will migrate to coastal areas in spring to breed. During the breeding season, males change colour, taking on a reddish/orange colouration. The population spawns over many months with spawning fish being caught in Iceland from March until August. Females which have spawned during the previous year tend to return to the same area when spawning again. They will also return at a similar time of year i. e. individuals which spawned early and late in the season will return to spawn early and late in the season the following year. A single female will lay 50,000–220,000 eggs which are laid in two batches of roughly equal size 1–2 weeks apart. The nest is in relatively shallow water (<) and may even be in the intertidal zone. Lumpfish are frequently caught in pelagic fishing nets, however, capture in bottom trawls is also common. An investigation using electronic data storage tags attached to the fish have confirmed that, at least during its breeding migration, this fish will spend time associated with the sea bed, and also some time in the pelagic zone. As the fish came close to breeding, they began to spend a greater amount of time in the pelagic zone. With the lack of a swim bladder, the fish were able to make rapid movements through the water column, moving between surface waters and depths of over within one day. Data from research surveys and data storage tags show that adult lumpfish alter their behaviour between night and day with the fish spending more time in the pelagic zone at night and found associated with the seabed during the day, the reasons for this are unclear. that is, when they are illuminated, light absorbed by the organism is remitted in lower energy wavelengths. The light reemitted by lumpfish appears green to the human observer and peaks at 545 and 613 nm. The greatest intensity is along the tubercles of the high crest and the three longitudinal ridges. The purpose of this biofluorescence remains unclear and it is also not known if this is also exhibited by adult lumpfish.

Cyclopterus is fished for its roe, landings of lumpfish roe varied from approximately from 1977 to 2018. In recent years, Iceland and Greenland have been the two largest fishing nations in regards to lumpfish and account for >95% of the global catch. Historically, Norway and Canada also contributed significant amounts but due to a decrease in the price of salted roe, and a severe population decline in Canada, the contribution from these countries has decreased. these are now frozen and exported, mainly to China. In Iceland, there is also the tradition of catching the male fish, mainly for the local market. This is done using gillnets with a smaller mesh size than that used for the females. The males are targeted in January–February, which is earlier than the females which are targeted from March until August.

Cyclopterus populations in both Iceland and Norway, the population is monitored using data from scientific surveys and is currently above the long term average and considered to be healthy. In Greenland, no survey data is available and data on fishing effort and landings are monitored. The time series is short for this population however appears to be stable. The population in Canada appears to be depleted and the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) has classified this as threatened. There is a lack of data to reliably assess the abundance of lumpfish in the North Sea or Baltic Sea thus the population status of this area is unknown. The fishery in Greenland and Norway was certified by the Marine Stewardship Council in 2015 and 2017 respectively with these certifications being valid for 5 years. The fishery in Iceland was certified in 2014 but this was suspended in 2018 due to issues surrounding bycatch but regained certification in 2020.

Cyclopterus roe, a good source of omega 3 fatty acids, is used to produce relatively inexpensive caviar substitutes. The roe is removed from the fish and processed to remove connective tissue. The roe is stored in large barrels where it is salted. The roe is dyed either red or black and packed with a mould inhibitor such as sodium benzoate (E211). In Scandinavia the flesh of the fish is eaten.