The flathead sole (''Hippoglossoides elassodon'') 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 soft,

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension with water. Silt usually has a floury feel when ...

y or muddy bottoms at depths of up to . Its native habitat is the northern

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

, from the seas of

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

and

Okhotsk Okhotsk ( rus, Охотск, p=ɐˈxotsk) is an types of inhabited localities in Russia, urban locality (a urban-type settlement, work settlement) and the administrative center of Okhotsky District of Khabarovsk Krai, Russia, located at the mou ...

, 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 ...

and to the coast of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, as far south as

Point Reyes Point Reyes (, meaning "Point of the Kings") is a prominent cape and popular Northern California tourist destination on the Pacific coast. Located in Marin County, it is approximately west-northwest of San Francisco. The term is often applied ...

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 ...

. It grows to in length, and can weigh up to ; females are typically larger than males. Lifespan is at least 27 years for females and at least 30 years for males.

Description

The flathead sole is a right-eyed flounder with an oval-shaped body. Its upper surface is dark in colour, olive brown to reddish grey-brown, and may have dusky blotches; its underside is white with translucent areas. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal co ...

and

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

s also have dusky blotches. The

lateral line The lateral line, also called the lateral line organ (LLO), is a system of sensory organs found in fish, used to detect movement, vibration, and pressure gradients in the surrounding water. The sensory ability is achieved via modified epithelial ...

curves slightly around the

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

. The upper jaw is narrow in the middle and has one row of teeth.

Role in ecosystem

The flathead sole occupies an intermediate

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 A food chain is a linear network of links in a food web starting from producer organisms (such as grass or algae which produce their own food via photosynthesis) and ending at an apex predator species (like grizzly bears or killer whales), det ...

Diet

The flathead sole's diet consists of

zoobenthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

s such as

clam Clam is a common name for several kinds of bivalve molluscs. The word is often applied only to those that are edible and live as infauna, spending most of their lives halfway buried in the sand of the seafloor or riverbeds. Clams have two she ...

worms Worms may refer to: *Worm, an invertebrate animal with a tube-like body and no limbs Places *Worms, Germany, a city **Worms (electoral district) *Worms, Nebraska, U.S. *Worms im Veltlintal, the German name for Bormio, Italy Arts and entertainme ...

and

brittle star Brittle stars, serpent stars, or ophiuroids (; ; referring to the serpent-like arms of the brittle star) are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomo ...

s, as well as

fish Fish are aquatic, craniate, gill-bearing animals that lack limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of li ...

and

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting t ...

Predators

The main predators of the flathead sole are the

Pacific cod The Pacific cod (''Gadus macrocephalus)'' is a species of ray-finned fish in the family Gadidae. It is a bottom-dwelling fish found in the northern Pacific Ocean, mainly on the continental shelf and upper slopes, to depths of about . It can grow ...

Alaska pollock The Alaska pollock or walleye pollock (''Gadus chalcogrammus'') is a marine fish species of the cod genus ''Gadus'' and family Gadidae. It is a semi-pelagic Shoaling and schooling, schooling fish widely distributed in the North Pacific Ocean, N ...

arrowtooth flounder The arrowtooth flounder (''Atheresthes stomas'') is a fish in the family Pleuronectidae. It can be caught from the Bering Sea to Santa Rosa Island, California. At present, it is the most common fish in the Gulf of Alaska. Data is insufficient fo ...

Greenland turbot The Greenland halibut or Greenland turbot (''Reinhardtius hippoglossoides'') belongs to the family Pleuronectidae (the right-eye flounders), and is the only species of the genus ''Reinhardtius''. It is a predatory fish that mostly ranges at dept ...

and

Pacific halibut The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

Commercial fishing

The U.S. lands the majority of the world's catch of flathead sole and manages three fisheries - one in the Bering Sea and

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 ...

, one in the

Gulf of Alaska The Gulf of Alaska (Tlingit: ''Yéil T'ooch’'') is an arm of the Pacific Ocean defined by the curve of the southern coast of Alaska, stretching from the Alaska Peninsula and Kodiak Island in the west to the Alexander Archipelago in the east, ...

and one off the

West Coast West Coast or west coast may refer to: Geography Australia * Western Australia *Regions of South Australia#Weather forecasting, West Coast of South Australia * West Coast, Tasmania **West Coast Range, mountain range in the region Canada * Britis ...

Commercial fishing Commercial fishing is the activity of catching fish and other seafood for commercial profit, mostly from wild fisheries. It provides a large quantity of food to many countries around the world, but those who practice it as an industry must often ...

is conducted by trawler. Annual catches average around 17,000 tons in the Bering Sea and Aleutian Islands area; in 2008 the Gulf of Alaska catch reached its highest ever level of 3,396 tons. The discard rate for each area is around 10%. Flathead sole is not currently

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 ...

, and

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 ...

is estimated to be above the level required to support the

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 the Bering Sea and Aleutian Islands area, biomass was estimated at 535,356 tons in 2008, down from a peak of almost 800,000 tons in 1997; in the Gulf of Alaska, biomass was estimated at 280,000 tons in 2007, where biomass has fluctuated around an average of 220,000 tons since 1984.

References

{{Taxonbar, from=Q3135992

flathead sole The flathead sole (''Hippoglossoides elassodon'') is a flatfish of the family Pleuronectidae. It is a demersal fish that lives on soft, silty or muddy bottoms at depths of up to . Its native habitat is the northern Pacific, from the seas of Japan ...

Fish of the North Pacific Western North American coastal fauna Commercial fish