Redfishes

Redfishes (Sebastes spp.) are among the most common fishes in Icelandic waters. They are also in some fundamental ways different from other common groundfish groups such as codfishes and flatfishes. Primarily because redfishes grow very old compared to other common fish species in Icelandic waters and furthermore they are viviparous. An accurate maximum age is impossible to verify, as old and slow growing fish are difficult to age determine. Age of maturity can be used as an proxy for maximum age, as old growing fishes generally mature late. Redfishes mature at the age of 12 to 15, compared to for example 5 to 7 for cod and saithe.

The three, or possibly four, redfish species occurring in Icelandic waters all look quite similar, and a trained eye is in many cases needed to identify them. Furthermore, one of the species is split up into two stocks that have quite different life styles.

The most common species and the best known is the golden redfish (Sebastes marinus), previously just called redfish. This has been the most common species in catches since redfish fisheries began. The Norway redfish (Sebastes viviparous), called little redfish in Icelandic is fairly common in shallower waters than the other species. However, it is quite small and therefore of little commercial interest. The third species is the deepwater and oceanic (or pelagic) redfish (Sebastes mentella); these are actually the names for the two separate stocks of the same species, as the species in general does not have a common English name. These two stocks are also targeted by different fishing gear as the oceanic redfish is exclusively pelagic, but the deepwater redfish can be both demersal and pelagic. The possible fourth species is the centennial redfish. Redfishes can grow very old, and exceptionally large individuals of golden redfish were previously called centennial redfishes as they were thought to be possibly more than 100 years old. However, recent analyses do indicate that they are somewhat genetically different from normal sized golden redfish. However, further studies are needed to verify if they are really different species. Despite its commercial importance, the species and stock composition of the redfish complex in Icelandic waters is, therefore, not well known.

In general, the redfish species inhabit different depth strata, although two or even three species can occur together in catches. The Norway redfish lives most shallow, or usually above 100 m depth, below that the golden redfish is most common from about 100 m to 400 m depth. Further down the deep sea redfish is most common from 500 to 700 m depth in the demersal zone, but deeper in the pelagic zone. In the pelagic zone above 500 m depth the oceanic redfish reigns.

Editor