The northern rock sole (''Lepidopsetta polyxystra'') is a

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish order (biology), order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the ...

of the family

Pleuronectidae Pleuronectidae, also known as righteye flounders, are a family of flounders. They are called "righteye flounders" because most species lie on the sea bottom on their left sides, with both eyes on their right sides. The Paralichthyidae are the op ...

. It is a

demersal The demersal zone is the part of the sea or ocean (or deep lake) consisting of the part of the water column near to (and significantly affected by) the seabed and the benthos. The demersal zone is just above the benthic zone and forms a layer of ...

fish that lives on sand, mud and gravel bottoms at depths of up to , though it is most commonly found between . Its native habitat is the

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

waters of the northern Pacific, from

Puget Sound Puget Sound ( ) is a sound of the Pacific Northwest, an inlet of the Pacific Ocean, and part of the Salish Sea. It is located along the northwestern coast of the U.S. state of Washington. It is a complex estuarine system of interconnected ma ...

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

(overlapping the range of the

rock sole The rock sole (''Lepidopsetta bilineata''), also known as the Pacific rock sole or Southern rock sole is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on sand and gravel bottoms at depths of up to , though it is most c ...

), the

Aleutian Islands The Aleutian Islands (; ; ale, Unangam Tanangin,”Land of the Aleuts", possibly from Chukchi language, Chukchi ''aliat'', "island"), also called the Aleut Islands or Aleutic Islands and known before 1867 as the Catherine Archipelago, are a cha ...

and across the

Bering Sea The Bering Sea (, ; rus, Бе́рингово мо́ре, r=Béringovo móre) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasses on Earth: Eurasia and The Ameri ...

to the

Kuril Islands The Kuril Islands or Kurile Islands (; rus, Кури́льские острова́, r=Kuril'skiye ostrova, p=kʊˈrʲilʲskʲɪjə ɐstrɐˈva; Japanese: or ) are a volcanic archipelago currently administered as part of Sakhalin Oblast in the ...

and the

Sea of Okhotsk The Sea of Okhotsk ( rus, Охо́тское мо́ре, Ohótskoye móre ; ja, オホーツク海, Ohōtsuku-kai) is a marginal sea of the western Pacific Ocean. It is located between Russia's Kamchatka Peninsula on the east, the Kuril Islands ...

(overlapping the range of the dusky sole). Males grow up to in length, whilst females can reach . The maximum recorded lifespan is 18 years.

Taxonomy and nomenclature

Prior to 2000 the Northern rock sole and the

, ''Lepidopsetta bilineata'', were considered to be a single species under the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

Lepidopsetta ''Lepidopsetta'' is a genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biolo ...

'', 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

The Northern rock sole occupies a moderately high

trophic level The trophic level of an organism is the position it occupies in a food web. A food chain is a succession of organisms that eat other organisms and may, in turn, be eaten themselves. The trophic level of an organism is the number of steps it i ...

in the food chain.

Diet

The diet of the Northern rock sole consists mainly of zoobenthos polychaetes and amphipods.

Predators

Northern rock sole are eaten by marine mammals and other fish, including

shark Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...

s, Alaska pollock,

yellowfin sole The yellowfin sole (''Limanda aspera'') is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on soft, sandy bottoms at depths of up to , though it is most commonly found at depths of around . Its native habitat is the te ...

, Pacific halibut and Pacific cod.

Reproduction

Northern rock sole reach reproductive maturity at between 4 and 7 years old, and

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: Ar ...

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.

Commercial fishing

Northern rock sole is fished commercially, and forms an important part of two

trawl Trawling is a method of fishing that involves pulling a fishing net through the water behind one or more boats. The net used for trawling is called a trawl. This principle requires netting bags which are towed through water to catch different speci ...

fisheries Fishery can mean either the enterprise of raising or harvesting fish and other aquatic life; or more commonly, the site where such enterprise takes place ( a.k.a. fishing ground). Commercial fisheries include wild fisheries and fish farms, both ...

in the Bering Sea and Gulf of Alaska. Although it was

overfished Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing fish stock), resulting in the ...

in the 1960s stocks have recovered, and the

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

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 population ecology and economics, maximum sustainable yield (MSY) is theoretically, the largest yield (or catch) that can be taken from a species' stock over an indefinite period. Fundamental to the notion of sustainable harvest, the concept of ...

. 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. Northern rock sole fishing off the coast of the

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

is managed by the North Pacific Fishery Management Council, one of eight

U.S. Regional Fishery Management Councils The eight U.S. regional fishery management councils are the primary forums for developing conservation and management measures for U.S. marine fisheries. The regional councils recommend management measures for fisheries in the Exclusive Economic ...

References

{{DEFAULTSORT:sole, rock, northern

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 , though it is most commonly found between . Its native habitat i ...

Fauna of the Northwestern United States Commercial fish