Greenland halibut
Encyclopedia
The Greenland halibut or Greenland turbot (Reinhardtius hippoglossoides) belongs to the Pleuronectidae
family (the right eye flounders), and is the only species
of the genus Reinhardtius. It is a deepwater fish distributed from 200 to 1600 m but has been caught at depths more than 2200 m (7,217.8 ft). It is mainly found in waters with temperatures from 1-4 °C, but has also observed at sub-zero temperatures down to -2.1 °C. It has a circumpolar distribution and is found in both the Atlantic and the Pacific oceans.
Its morphology with the left eye positioned on the dorsal ridge of the forehead gives it an appearance of a cyclops
when looking straight at it. The central position of the left eye in the Greenland halibut probably gives it a much wider range of peripheral vision
in comparison to other flatfish where the eye has migrated completely. The body shape is elongated and compressed dorsal-ventrally and muscles on both sides are equally developed. Both sides are pigmented; however the left blind side is slightly lighter in color than the right side.
Its physical appearance suggests it to be a vigorous swimmer that can swim in a vertical position. Vertical swimming has been observed during tagging experiments. However, video analyzing of Greenland halibut behavior in front of a bottom trawl showed no sign of swimming in a vertical position. Even though most Greenland halibut are caught in bottom fishing gears (trawl, longline and gillnet
) they have also been caught in surface drift nets which indicates that they can have a pelagic occurrence. Stomach analysis has also shown that the diet consists mostly of pelagic or bathypelagic organisms. Even though the Greenland halibut is a flatfish it does at times behave more like a roundfish.
Pleuronectidae
Righteye flounders are a family, Pleuronectidae, of flounders. They are called "righteye flounders" because most species lie on the sea bottom on their left side, with both eyes on the right side. The Paralichthyidae are the opposite, with their eyes on the left side.Their dorsal and anal fins are...
family (the right eye flounders), and is the only species
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
of the genus Reinhardtius. It is a deepwater fish distributed from 200 to 1600 m but has been caught at depths more than 2200 m (7,217.8 ft). It is mainly found in waters with temperatures from 1-4 °C, but has also observed at sub-zero temperatures down to -2.1 °C. It has a circumpolar distribution and is found in both the Atlantic and the Pacific oceans.
Its morphology with the left eye positioned on the dorsal ridge of the forehead gives it an appearance of a cyclops
Cyclops
A cyclops , in Greek mythology and later Roman mythology, was a member of a primordial race of giants, each with a single eye in the middle of his forehead...
when looking straight at it. The central position of the left eye in the Greenland halibut probably gives it a much wider range of peripheral vision
Peripheral vision
Peripheral vision is a part of vision that occurs outside the very center of gaze. There is a broad set of non-central points in the field of view that is included in the notion of peripheral vision...
in comparison to other flatfish where the eye has migrated completely. The body shape is elongated and compressed dorsal-ventrally and muscles on both sides are equally developed. Both sides are pigmented; however the left blind side is slightly lighter in color than the right side.
Its physical appearance suggests it to be a vigorous swimmer that can swim in a vertical position. Vertical swimming has been observed during tagging experiments. However, video analyzing of Greenland halibut behavior in front of a bottom trawl showed no sign of swimming in a vertical position. Even though most Greenland halibut are caught in bottom fishing gears (trawl, longline and gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
) they have also been caught in surface drift nets which indicates that they can have a pelagic occurrence. Stomach analysis has also shown that the diet consists mostly of pelagic or bathypelagic organisms. Even though the Greenland halibut is a flatfish it does at times behave more like a roundfish.