Hexagrammidae, the greenlings, is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

of marine

ray-finned fish 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 ...

es belonging to the

suborder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Cottoidei Cottoidei is a suborder of ray-finned fishes which, according to the 5th edition of ''Fishes of the World'', is placed within the order Scorpaeniformes, alongside the scorpionfishes, flatheads, eelpouts,sticklebacks and related fishes. Taxonom ...

in the order

Scorpaeniformes The Scorpaeniformes are a diverse order of ray-finned fish, including the lionfishes and sculpins, but have also been called the Scleroparei. It is one of the five largest orders of bony fishes by number of species, with over 1,320. They are ...

. These fishes are found in the

North Pacific Ocean North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating direction or geography. Etymology The word ''north'' is ...

Taxonomy

Hexagrammidae was first proposed as a family in 1888 by the American

ichthyologist Ichthyology is the branch of zoology devoted to the study of fish, including bony fish ( Osteichthyes), cartilaginous fish (Chondrichthyes), and jawless fish (Agnatha). According to FishBase, 33,400 species of fish had been described as of Octobe ...

David Starr Jordan David Starr Jordan (January 19, 1851 – September 19, 1931) was the founding president of Stanford University, serving from 1891 to 1913. He was an ichthyologist during his research career. Prior to serving as president of Stanford Univer ...

. The 5th edition of ''

Fishes of the World ''Fishes of the World'' by the American ichthyologist Joseph S. Nelson (1937–2011) is a standard reference for fish systematics. Now in its fifth edition (2016), the work is a comprehensive overview of the diversity and classification of the ...

'' clasifies this family as the only family in the

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

Hexagrammoidea within the suborder Cottoidei of the diverse order Scorpaeniformes. Other workers have found that if the Scorpaeniformes, as delimited in ''Fishes of the World'', is not included in the

Perciformes Perciformes (), also called the Percomorpha or Acanthopteri, is an order or superorder of ray-finned fish. If considered a single order, they are the most numerous order of vertebrates, containing about 41% of all bony fish. Perciformes means ...

it renders the Perciformes

paraphyletic In taxonomy (general), taxonomy, a group is paraphyletic if it consists of the group's most recent common ancestor, last common ancestor and most of its descendants, excluding a few Monophyly, monophyletic subgroups. The group is said to be pa ...

. These workers retain the Cottoidei as a suborder within the

while reclassifying Hexagrammoidea as the

infraorder Order ( la, ordo) is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and ...

Hexagrammales. The family Zaniolepididae has been included within the Hexagrammidae, as the subfamilies

Zaniolepidinae ''Zaniolepis'', the combfishes, is a genus of marine ray-finned fish, it is one of two genera in the family Zaniolepididae. These fishes are native to the eastern Pacific Ocean. ''Z. frenata'' that was a source of food to the Native American i ...

and Oxylebiinae, but ''Fishes of the World'' and Betancur ''et al'' classify these taxa as distinct from the Hexagrammidae. The palcing of these two families in their own monotypic superfamilies was originally proposed in 1994 by Gento Shinohara.

Subfamilies and genera

Hexagrammidae contains the following subfamilies and genera: * Subfamily Ophiodontinae Jordan &

Gilbert Gilbert may refer to: People and fictional characters * Gilbert (given name), including a list of people and fictional characters *Gilbert (surname), including a list of people Places Australia * Gilbert River (Queensland) * Gilbert River (South ...

, 1883 ** Genus '' Ophiodon'' Girard, 1854 * Subfamily Hexagramminae Jordan, 1888 ** Genus ''

Hexagrammos ''Hexagrammos'' is a genus of marine ray-finned fishes belonging to the family Hexagrammidae, the greenlings. These fishes are found in the north Pacific Ocean. Taxonomy ''Hexagrammos'' was first proposed as a monospecific genus in 1810 by the ...

'' Tilesius, 1810 *Subfamily Pleurogramminae Rutenberg, 1954 ** Genus '' Pleurogrammus''

Gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

, 1861

Characteristics

Hexagrammidae have cirrhi but do not have ridges or spines on their heads, They have between one and five

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 ...

s and may have

cycloid In geometry, a cycloid is the curve traced by a point on a circle as it rolls along a straight line without slipping. A cycloid is a specific form of trochoid and is an example of a roulette, a curve generated by a curve rolling on another curve ...

ctenoid scale A fish scale is a small rigid plate that grows out of the skin of a fish. The skin of most jawed fishes is covered with these protective scales, which can also provide effective camouflage through the use of reflection and colouration, as we ...

s. There is a single

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

which is notched and contains between 16 and 28 spines and 11 and 30 soft rays. There is a single spine and 5 soft rays in the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods. Structure and function Structure In actinopterygians, the pelvic fin consists of two en ...

. The front nostril on each side of the snout is well developed but the rear nostril may be absent or if it is there it is merely a small pore. The

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 ...

may have upn to 3 spines, or there may be no spines, and 6 or 7 soft rays. There is no swimbladder. The largest species is the lingcod (''Ophiodon elongatus'')which has a maximum publsihed

total length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish ...

of but typically they are or less in length.

Distribution and habitat

Hexagrammidae is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the North Pacific Ocean where they are found in the subarctic and temperate regions, with a single species, the whitespotted greenling '' Hexagrammos stelleri'', being found in the Arctic Ocean too. They occur from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

to as deep as but most are found in waters of depths of less than on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

Biology

Hexagrammidae greenlings are

demersal fish Demersal fish, also known as groundfish, live and feed on or near the bottom of seas or lakes (the demersal zone).Walrond Carl . "Coastal fish - Fish of the open sea floor"Te Ara - the Encyclopedia of New Zealand. Updated 2 March 2009 They occ ...

es, except for the

pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or wa ...

''Pleurogrammus'', and they feed on crustaceans, polychaetes, small fishes and fish eggs.

Utilization

Hexagrammidae greenlings are fished for, the coastal species are fished for using hook and line and

spears A spear is a pole weapon consisting of a shaft, usually of wood, with a pointed head. The head may be simply the sharpened end of the shaft itself, as is the case with fire hardened spears, or it may be made of a more durable material fastene ...

and in the late 20th and early 21st centuries the

kelp greenling The kelp greenling (''Hexagrammos decagrammus'') is a species of marine ray-finned fish belonging to the family Hexagrammidae, the greenlings. It occurs in the eastern Pacific Ocean Species description and etymology The kelp greenling was fir ...

(''Hexagrammas decagrammus'') has become a taraget of a commercial fishery, while historically the lingcod (''O. elongatus'') and the

atka mackerel The Atka mackerel (''Pleurogrammus monopterygius'') is a mackerel in the family Hexagrammidae. Atka mackerel are common in the northern Pacific ocean, and are one of only two members of the genus '' Pleurogrammus'' - the other being the Arabe ...

s of the genus ''Pleurogrammus'' have been the most targeted species.

References

* * {{Taxonbar, from=Q1552315 Cottoidei Ray-finned fish families *