03 Oct Deep-water redfish / Sebastes mentella / Djúpkarfi
Djúpkarfi / Deep-water redfish / Sebastes mentella
Deep-water redfish looks very much like its cousin, the golden redfish. However, its stomach is redder and its whole colouring more even. Also the bony protrusion at the front of the lower jaw is larger and the lowest spikes of the chin bones bend forward. An easy way to find out if the fish in question really is a deep-water redfish is to slide the thumb backwards over the chin bones. If the thumb gets scratched, the fish is a deep-water redfish.
Deep-water redfish is found in the Northern Atlantic along the coast of eastern Greenland, south-west and south of Iceland, along the deep-sea ridge leading to the Faeroe Islands, around the islands to the north of Great Britain, off Lofoten and in the Barents Sea towards Svalbard. It is thought that the deep-water redfish off Greenland, Iceland and the Faeroe Islands are a different stock from the deep-water redfish found in the Barents Sea.
The main fishing grounds for deep-water redfish around Iceland are deep on the Faeroe Islands’ ridge off the south-west coast of the country. A fully grown deep-water redfish is not commonly found off Northern Iceland.
Deep-water redfish keeps to the sea floor and the mid-ocean at a depth of five hundred to eight hundred metres, but it has been caught at a depth of about one thousand metres. It can reach the length of about seventy centimetres, but is most often thirty-five to forty-five centimetres in length. The longevity of this fish is not easily determined, but using isotope ratios, scientists have found that the deep-water redfish can reach the age of sixty-five to seventy-five years.
The deep-water redfish bears living young. The eggs are hatched inside the fish and the spawning occurs in March to May at a depth of five hundred to seven hundred metres in waters of about six degrees Celsius. The number of eggs for each female is between forty and four hundred, and when hatched the fingerlings are seven to eight millimetres in length. The fingerlings drift on the ocean currents towards Greenland, where they seek the sea floor on the underwater shelf at a depth of two to four hundred metres in waters of three to four degrees Celsius. Growth is slow, and pubescence is not reached until the fish has grown to thirty-seven to forty-two centimetres in length.
As the main habitat of the deep-water redfish lies quite far down in the ocean, it was not a common catch until late in the twentieth century, when trawlers got larger and more efficient for deep-water fishing. In later years this fish has been heavily caught, so much so that ichthyologists have started worrying about the state of the stock. However, as the deep-water redfish is mainly caught in international waters, it has proved difficult to reach agreements on regulatory measures.