The southern smoothtongue or California smoothtongue (''Leuroglossus stilbius'') is a type of

ray-finned Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species. The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...

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 ...

in the

deep-sea smelt The deep-sea smelts are any members of the family Bathylagidae, a distinct group of marine smelts. Deep-sea smelts are marine fishes found in deep waters throughout the oceans, down to in depth. They are small fishes, growing up to long. They ...

family

Bathylagidae The deep-sea smelts are any members of the family (biology), family Bathylagidae, a distinct group of marine smelts. Deep-sea smelts are marine fishes found in deep waters throughout the oceans, down to in depth. They are small fishes, growing ...

, that can grow to a length of TL. This fish is native to the northeastern

Pacific Ocean 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

British Columbia British Columbia (commonly abbreviated as BC) is the westernmost province of Canada, situated between the Pacific Ocean and the Rocky Mountains. It has a diverse geography, with rugged landscapes that include rocky coastlines, sandy beaches, ...

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, and the

Gulf of California The Gulf of California ( es, Golfo de California), also known as the Sea of Cortés (''Mar de Cortés'') or Sea of Cortez, or less commonly as the Vermilion Sea (''Mar Bermejo''), is a marginal sea of the Pacific Ocean that separates the Baja Ca ...

where it is found at depths of .

Description

The California smoothtongue is a slender fish growing to a length of about . The dorsal fin has 9 to 12 soft rays, the anal fin 11 to 14, the pectoral fin 8 to 9 and the pelvic fin 8 to 10. The dorsal fin is set well back on the body and the tail fin is deeply forked. The pectoral fins are small and positioned low down on the belly. The fish is darker above and paler below, being silvery or bronze with pale-coloured fins. A distinguishing feature for this fish is that the length of the pointed snout is greater than the diameter of the eye. These fish are called "smoothtongue" because of their relative absence of teeth, with none on the premaxilla and tongue, and few on the jaws and the roof of the mouth.

Biology

The California smoothtongue is the most common midwater fish off

Santa Barbara, California Santa Barbara ( es, Santa Bárbara, meaning "Saint Barbara") is a coastal city in Santa Barbara County, California, of which it is also the county seat. Situated on a south-facing section of coastline, the longest such section on the West Coas ...

. It makes daily vertical migrations. In the late afternoon and earlier part of the night it is to be found near the surface of the sea feeding mainly on

salp A salp (plural salps, also known colloquially as “sea grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient ...

s and

larvacea Larvaceans, class Appendicularia, are solitary, free-swimming tunicates found throughout the world's oceans. Like most tunicates, larvaceans are filter feeders. Unlike most other tunicates, they live in the pelagic zone, specifically in the pho ...

ns; its mouth is adapted to pull in these inactive, gelatinous prey items by suction. It also consumes some

ostracod Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...

copepod Copepods (; meaning "oar-feet") are a group of small crustaceans found in nearly every freshwater and saltwater habitat (ecology), habitat. Some species are planktonic (inhabiting sea waters), some are benthos, benthic (living on the ocean floor) ...

s and fish eggs. In the later part of the night it descends to deeper parts of the sea while in the morning it is at mid-depths. The fish has a double-chambered stomach, the first chamber having a black pigment in its lining which may prevent the light from

luminescent Luminescence is spontaneous emission of light by a substance not resulting from heat; or "cold light". It is thus a form of cold-body radiation. It can be caused by chemical reactions, electrical energy, subatomic motions or stress on a cryst ...

prey it has swallowed from being visible from the exterior. The Californian smoothtongue is an

oviparous Oviparous animals are animals that lay their eggs, with little or no other embryonic development within the mother. This is the reproductive method of most fish, amphibians, most reptiles, and all pterosaurs, dinosaurs (including birds), and ...

(egg-laying) fish. Both eggs and larvae drift with the

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

. This fish is plentiful at medium depths and forms part of the diet of larger fish, seabirds,

sea lion Sea lions are pinnipeds characterized by external ear flaps, long foreflippers, the ability to walk on all fours, short and thick hair, and a big chest and belly. Together with the fur seals, they make up the family Otariidae, eared seals. ...

dolphin A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...

s and the

Humboldt squid The Humboldt squid (''Dosidicus gigas''), also known as jumbo squid or jumbo flying squid (EN), and Pota in Peru or Jibia in Chile (ES) is a large, predatory squid living in the eastern Pacific Ocean. It is the only known species of the genus ''D ...

References

External links

* {{Authority control Bathylagidae Fish of the Pacific Ocean Fish of the United States Fish described in 1890