The rex sole (''Glyptocephalus zachirus'') is a

flatfish A flatfish is a member of the Ray-finned fish, ray-finned demersal fish Order (biology), suborder Pleuronectoidei, also called the Heterosomata. In many species, both eyes lie on one side of the head, one or the other migrating through or around ...

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 o ...

. Locally, it may also be known as a witch or threadfin sole (due to the filamentous pelvic fin on the eyed surface). 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 o ...

fish that lives in

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

waters on sand or mud bottoms at depths of up to , though it is most commonly found between . 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 the definition, to Antarctica in the south, and is bounded by the cont ...

, from

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

up the coasts of the

United States The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 U.S. state, states and a federal capital district, Washington, D.C. The 48 ...

British Columbia British Columbia is the westernmost Provinces and territories of Canada, province of Canada. Situated in the Pacific Northwest between the Pacific Ocean and the Rocky Mountains, the province has a diverse geography, with rugged landscapes that ...

and

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

, across the

Bering Sea The Bering Sea ( , ; rus, Бе́рингово мо́ре, r=Béringovo móre, p=ˈbʲerʲɪnɡəvə ˈmorʲe) is a marginal sea of the Northern Pacific Ocean. It forms, along with the Bering Strait, the divide between the two largest landmasse ...

to the coast of

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

and the

Sea of Japan The Sea of Japan is the marginal sea between the Japanese archipelago, Sakhalin, the Korean Peninsula, and the mainland of the Russian Far East. The Japanese archipelago separates the sea from the Pacific Ocean. Like the Mediterranean Sea, it ...

. It is slow-growing, reaching up to in length (though its average length is ), and it can weigh up to . Maximum reported lifespan is 24 years.

Description

The rex sole is a right-eyed flounder with an elongate, oval-shaped body and a small mouth. Its upper surface is uniform in colour, light brown to grey, with small scales; its underside is off-white. The dorsal and ventral fins on the upper side are dark, and the pectoral fin is long and mostly black. The caudal fin is rounded. The lateral line is nearly straight.

Diet

The rex sole's diet consists of

benthos 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 animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s such as

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

worm Worms are many different distantly related bilateria, bilateral animals that typically have a long cylindrical tube-like body, no limb (anatomy), limbs, and usually no eyes. Worms vary in size from microscopic to over in length for marine ...

shrimp A shrimp (: shrimp (American English, US) or shrimps (British English, UK)) is a crustacean with an elongated body and a primarily Aquatic locomotion, swimming mode of locomotion – typically Decapods belonging to the Caridea or Dendrobranchi ...

s and

crab Crabs are decapod crustaceans of the infraorder Brachyura (meaning "short tailed" in Greek language, Greek), which typically have a very short projecting tail-like abdomen#Arthropoda, abdomen, usually hidden entirely under the Thorax (arthropo ...

Commercial fishing

The rex sole is fished commercially, and its flesh is considered tasty. Commercial fishing is conducted by trawler and the fish comprises a major part of the flatfish trawl fishery from California northward to the Bering Sea.

References

rex sole Fish of the North Pacific Western North American coastal fauna Taxa named by William Neale Lockington rex sole {{Pleuronectiformes-stub