Grenadiers or rattails are generally large, brown to black gadiform marine

fish A fish (: fish or fishes) is an aquatic animal, aquatic, Anamniotes, anamniotic, gill-bearing vertebrate animal with swimming fish fin, fins and craniate, a hard skull, but lacking limb (anatomy), limbs with digit (anatomy), digits. Fish can ...

of the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

Macrourinae, the largest subfamily of the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Macrouridae Macrouridae is a family of deep sea fish, a diverse and ecologically important group, which are part of the order of cod-like fish, the Gadiformes. The species in the Macrouridae are characterised by their large heads which normally have a sing ...

. Found at great depths from the

Arctic The Arctic (; . ) is the polar regions of Earth, polar region of Earth that surrounds the North Pole, lying within the Arctic Circle. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( ...

Antarctic The Antarctic (, ; commonly ) is the polar regions of Earth, polar region of Earth that surrounds the South Pole, lying within the Antarctic Circle. It is antipodes, diametrically opposite of the Arctic region around the North Pole. The Antar ...

, members of this subfamily are amongst the most abundant of the deep-sea fish. The macrourins form a large and diverse family with 28 extant genera recognized (well over half of the total

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

are contained in just three genera, '' Coelorinchus'', '' Coryphaenoides'', and '' Nezumia''). They range in length from about in ''Hymenogadus gracilis'' to in ''Albatrossia pectoralis''. Several attempts have been made to establish a commercial fishery for the most common larger species, such as the giant grenadier, but the fish is considered unpalatable, and attempts thus far have proven unsuccessful. The subfamily as a whole may represent up to 15% of the deep-sea fish population. Rattails, characterized by large heads with large mouths and eyes, have slender bodies that taper very much to very thin caudal peduncles or tails (except for one species without a caudal fin): this rat-like tail explains the common name "rattail" and the name of the subfamily and the surname are derived from the Greek makros meaning "big" and Oura meaning "tail". The first dorsal flat is small, tall and pointed (and may have rays modified into spines); The second dorsal fin runs along the rest of the back and connects to the tail and the large anal fin. The scales are small. As with many deep-living fish, 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 epithelia ...

system in grenadiers is well-developed; it is further aided by numerous

chemoreceptor A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance ( endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemorece ...

s located on the head and lips and chemosensory

barbel Barbel may refer to: *Barbel (anatomy), a whisker-like organ near the mouth found in some fish (notably catfish, loaches and cyprinids) and turtles *Barbel (fish), a common name for certain species of fish **''Barbus barbus'', a species of cyprini ...

s underneath the chin.

Benthic The benthic zone is the ecological region at the lowest level of a body of water such as an ocean, lake, or stream, including the sediment surface and some sub-surface layers. The name comes from the Ancient Greek word (), meaning "the depths". ...

species have

swim bladder The swim bladder, gas bladder, fish maw, or air bladder is an internal gas-filled organ (anatomy), organ in bony fish that functions to modulate buoyancy, and thus allowing the fish to stay at desired water depth without having to maintain lift ...

s with unique muscles attached to them. The animals are thought to use these muscles to "strum" their bladders and produce sound, possibly playing a role in courtship and mate location. Light-producing organs,

photophore A photophore is a specialized anatomical structure found in a variety of organisms that emits light through the process of boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generated through a mut ...

s, are present in some species; they are located in the middle of the abdomen, just before the anus and underneath the skin. Rattail

Grenadiers have been recorded from depths of about , and are among the most common benthic fish of the deep (however, two genera are known to prefer the midwater). They may be solitary or may form large schools, as with the roundnose grenadiers. The benthic species are attracted to structural oases, such as

hydrothermal vent Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...

cold seep A cold seep (sometimes called a cold vent) is an area of the ocean floor where seepage of fluids rich in hydrogen sulfide, methane, and other hydrocarbons occurs, often in the form of a brine pool. ''Cold'' does not mean that the temperature ...

s, and

shipwreck A shipwreck is the wreckage of a ship that is located either beached on land or sunken to the bottom of a body of water. It results from the event of ''shipwrecking'', which may be intentional or unintentional. There were approximately thre ...

s. They are thought to be generalists, feeding on smaller fish, pelagic

crustacea 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 ...

ns, such as

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 ...

, amphipods,

cumacea Cumacea is an order (biology), order of small marine crustaceans of the superorder Peracarida, occasionally called hooded shrimp or comma shrimp. Their unique appearance and uniform body plan makes them easy to distinguish from other crustaceans. ...

ns, and less often

cephalopod A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...

s and

lanternfish Lanternfish (or myctophids, from the Greek language, Greek μυκτήρ ''myktḗr'', "nose" and ''ophis'', "serpent") are small mesopelagic fish of the large family (biology), family Myctophidae. One of two families in the order Myctophiformes, ...

. As well as being important

apex predator An apex predator, also known as a top predator or superpredator, is a predator at the top of a food chain, without natural predators of its own. Apex predators are usually defined in terms of trophic dynamics, meaning that they occupy the hig ...

s in the benthic habitat, some species are also notable as scavengers. As few rattail

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e have been recovered, little is known of their life histories. They are known to produce a large number (over 100,000) of tiny ( in diameter) eggs made buoyant by

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

droplets. The eggs are presumed to float up to the

thermocline A thermocline (also known as the thermal layer or the metalimnion in lakes) is a distinct layer based on temperature within a large body of fluid (e.g. water, as in an ocean or lake; or air, e.g. an atmosphere) with a high gradient of distinct te ...

(the interface between warmer surface waters and cold, deeper waters) where they develop. The juveniles remain in shallower waters, gradually migrating to greater depths with age. Spawning may or may not be tied to the seasons, depending on the species. At least one species, '' Coryphaenoides armatus'', is thought to be

semelparous Semelparity and iteroparity are two contrasting reproductive strategies available to living organisms. A species is considered ''semelparous'' if it is characterized by a single reproduction, reproductive episode before death, and ''iteroparous ...

; that is, the adults die after spawning. Nonsemelparous species may live to 56 years or more. The macrourins, in general, are thought to have low resilience; commercially exploited species may be overfished and this could soon lead to a collapse of their fisheries.

Genera

Currently 28 extant genera in this subfamily are recognized:Iwamoto, T., Nakayama, N., Shao, K.-T. & Ho, H.-C. (2015): Synopsis of the Grenadier Fishes (Gadiformes; Teleostei) of Taiwan. ''Proceedings of the California Academy of Sciences, 62 (3): 31–126.'' * '' Albatrossia'' Jordan & Gilbert, 1898 * '' Asthenomacrurus'' Sazonov & Shcherbachev, 1982 * '' Cetonurichthys'' Sazonov & Shcherbachev, 1982 * '' Cetonurus'' Günther, 1887 * '' Coelorinchus'' Giorna, 1809 * '' Coryphaenoides'' Gunnerus, 1765 * '' Cynomacrurus'' Dollo, 1909 * '' Echinomacrurus'' Roule, 1916 * '' Haplomacrourus'' Trunov, 1980 * '' Hymenocephalus'' Giglioli, 1884 * '' Hymenogadus'' Gilbert & Hubbs, 1920 * '' Kumba'' Marshall, 1973 * '' Kuronezumia'' Iwamoto, 1974 * '' Lepidorhynchus'' Richardson, 1846 * ''

Lucigadus ''Lucigadus'' is a genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV clas ...

'' Gilbert & Hubbs, 1920 * '' Macrosmia'' Merrett, Sazonov & Shcherbachev, 1983 * '' Macrourus'' Bloch, 1786 * '' Malacocephalus'' Günther, 1862 * '' Mataeocephalus'' Berg, 1898 * '' Mesovagus'' Nakayama & Endo, 2016 Nakayama, N. & Endo, H. (2016): ''Mesovagus'', a replacement name for the grenadier genus ''Mesobius'' Hubbs and Iwamoto 1977 (Actinopterygii: Gadiformes: Macrouridae), a junior homonym of ''Mesobius'' Chamberlin 1951 (Chilopoda: Lithobiomorpha: Lithobiidae). ''Ichthyological Research, 64 (1): 120–122.'' * '' Nezumia'' Jordan, 1904 * '' Odontomacrurus'' Norman, 1939 * '' Paracetonurus'' Marshall, 1973 * '' Pseudocetonurus'' Sazonov & Shcherbachev, 1982 * '' Pseudonezumia'' Okamura, 1970 * ''

Sphagemacrurus ''Sphagemacrurus'' is a genus of rattails. Species There are currently six recognized species in this genus: * ''Sphagemacrurus decimalis'' (Charles Henry Gilbert, C. H. Gilbert & Carl Leavitt Hubbs, C. L. Hubbs, 1920) * ''Sphagemacrurus gibber' ...

'' Fowler, 1925 * '' Spicomacrurus'' Okamura, 1970 * '' Trachonurus'' Günther, 1887 * '' Ventrifossa'' Gilbert & Hubbs, 1920

References

{{Taxonbar, from=Q1883040 Macrouridae Taxa named by Charles Lucien Bonaparte

Genera

See also

References