Northern rock sole
|Northern rock sole|
The northern rock sole (Lepidopsetta polyxystra) is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on sand, mud and gravel bottoms at depths of up to 700 metres (2,300 ft), though it is most commonly found between 19 and 246 metres (62 and 807 ft). Its native habitat is the temperate waters of the northern Pacific, from Puget Sound to Alaska (overlapping the range of the rock sole), the Aleutian Islands and across the Bering Sea to the Kuril Islands and the Sea of Okhotsk (overlapping the range of the dusky sole). Males grow up to 69 centimetres (27 in) in length, whilst females can reach 49 centimetres (19 in). The maximum recorded lifespan is 18 years.
Taxonomy and nomenclature
Prior to 2000 the Northern rock sole and the rock sole, Lepidopsetta bilineata, were considered to be a single species under the genus Lepidopsetta, but work by Orr & Matarese published in 2000 reorganised the genus into three separate taxa.
As a result of this reclassification and renaming, the rock sole L. bilineata may be referred to as the "southern" rock sole, in order to avoid confusion with the Northern rock sole L. polyxystra.
Role in ecosystem
Northern rock sole reach reproductive maturity at between 4 and 7 years old, and spawn in winter through to early spring. Eggs are demersal and stick to the surface on which they are laid; hatching takes from 6 to 25 days.
Northern rock sole is fished commercially, and forms an important part of two trawl fisheries in the Bering Sea and Gulf of Alaska. Although it was overfished in the 1960s stocks have recovered, and the biomass of Northern rock sole in the Bering Sea and Aleutian Islands fishery is now estimated to be very high, at twice the level required to support maximum sustainable yield. In 2008 the estimated Northern rock sole biomass in the Gulf of Alaska fishery was some 102,303 tons, compared to catches ranging from 453 tons in 2004 to 4,330 tons in 2006.
- Ed. Ranier Froese and Daniel Pauly (15 July 2009). "Lepidopsetta polyxystra". Fishbase. Retrieved 2009-11-17.
- Orr, James W.; Matarese, Ann C. (July 2000). "Revision of the genus Lepidopsetta Gill, 1862 (Teleostei: Pleuronectidae) based on larval and adult morphology, with a description of a new species from the North Pacific Ocean and Bering Sea" (PDF). Fishery Bulletin. 98 (3): 539–82. Retrieved 2009-11-18.
- "Rock sole". FishWatch. National Marine Fisheries Service. 2009-10-29. Archived from the original on 2008-04-03. Retrieved 2009-11-18.
- Poltev, Y. N.; Labai, V. S.; Mukhametov, I. N. (August 2008). "On the diet of the rock sole Lepidopsetta polyxystra off the eastern coast of the northern Kuril Islands and the southern extremity of Kamchatka" (PDF). Journal of Ichthyology. 48 (7): 505–14. doi:10.1134/S0032945208070047. Retrieved 2009-11-18.