The Chilean jack mackerel (''Trachurus murphyi''), sometimes called the Inca scad or Peruvian jack mackerel, is a species of

jack mackerel Jack mackerels or saurels are marine fish in the genus ''Trachurus'' of the family Carangidae. The name of the genus derives from the Greek words ''trachys'' ("rough") and ''oura'' ("tail"). Some species, such as ''T. murphyi'', are harvested in ...

in the genus ''

Trachurus Jack mackerels or saurels are marine fish in the genus ''Trachurus'' of the family Carangidae. The name of the genus derives from the Greek words ''trachys'' ("rough") and ''oura'' ("tail"). Some species, such as ''T. murphyi'', are harvested in ...

'' of the family

Carangidae The Carangidae are a family of ray-finned fish which includes the jacks, pompanos, jack mackerels, runners, and scads. It is the largest of the six families included within the order Carangiformes. Some authorities classify it as the only family ...

. Since the 1970s, it has become one of the world's more important commercial fish species. High volumes have been harvested, but the fishery may now be in danger of collapsing.

Description

Chilean jack mackerels are commonly long, though they can grow to . They have elongated and laterally compressed bodies. The head is large with well-developed transparent protective membranes (the adipose eyelid) covering the eyes. The mouth is also large, with the rear edge of the lower jaw aligning with the front edge of the eyes. It possesses small teeth. Each

opercle The operculum is a series of bones found in bony fish and chimaeras that serves as a facial support structure and a protective covering for the gills; it is also used for respiration and feeding. Anatomy The opercular series contains four b ...

of the gill covers has a distinct notch on its rear edge. The second

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 ...

is much longer than the first. 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 ...

s are long and pointed. The origin of 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 ...

s is below the bottom point of attachment of the pectorals. 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 ...

is also long, but shorter than the second dorsal fin. At its front are two strong spines. The upper parts of the body are metallic blue in color, while the bottom surfaces are a silvery white.

Distribution and habitat

The Chilean jack mackerel is an

epipelagic fish Pelagic fish live in the pelagic zone of ocean or lake waters—being neither close to the bottom nor near the shore—in contrast with demersal fish that do live on or near the bottom, and reef fish that are associated with coral ree ...

that swims in

schools A school is an educational institution designed to provide learning spaces and learning environments for the teaching of students under the direction of teachers. Most countries have systems of formal education, which is sometimes compulsor ...

around coasts and in the open ocean. Normally it swims at depths between 10 and 70 m, but it can swim as deep as 300 m. They are found in the south Pacific off the coasts of Chile and Peru, around New Zealand and south Australia, and in a band across the open ocean in between. In 1993, Elizarov et al. referred to this band on the high seas as the 'jack mackerel belt'.Elizarov AA, Grechina AS, Kotenev BN and Kuzetsov AN (1993)
"Peruvian jack mackerel, Trachurus symmetricus murphyi, in the open waters of the South Pacific"
''Journal of Ichthyology'', 33: 86–104. The jack mackerel belt ranges from 35 to 45° S, which means it has a north–south breadth of 10° (about 1100 km). "Spawning groups concentrate mainly in the north of 40° S in spring and summer and south of 40° S in autumn and winter to feed". Chilean jack mackerel normally

spawn Spawn or spawning may refer to: * Spawn (biology), the eggs and sperm of aquatic animals Arts, entertainment, and media * Spawn (character), a fictional character in the comic series of the same name and in the associated franchise ** '' Spawn: ...

in summer. Their

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

are

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 ...

, that is, they float free in the open sea. Not enough data are available to know for sure the Chilean jack mackerel stock structure. However, four separate stocks have been proposed: "a Chilean stock which is a

straddling stock Fish stock or stock fish may also refer to: *Fish stocks are subpopulations of a particular species of fish. * Fish stock (food), liquid made by boiling fish bones with vegetables, used as a base for fish soups and sauces * Fish stocking, the practi ...

with respect to the

high seas The terms international waters or transboundary waters apply where any of the following types of bodies of water (or their drainage basins) transcend international boundaries: oceans, large marine ecosystems, enclosed or semi-enclosed regiona ...

; a Peruvian stock which is also a straddling stock with the high seas; a central Pacific stock which exists solely in the high seas; and, a southwest Pacific stock which straddles the high seas and both the New Zealand and Australian EEZs."

Ecology

Chilean jack mackerels mainly eat

fish larvae Ichthyoplankton (from Greek: ἰχθύς, , "fish"; and πλαγκτός, , "drifter") are the eggs and larvae of fish. They are mostly found in the sunlit zone of the water column, less than 200 metres deep, which is sometimes called the epi ...

shrimp Shrimp are crustaceans (a form of shellfish) with elongated bodies and a primarily swimming mode of locomotion – most commonly Caridea and Dendrobranchiata of the decapod order, although some crustaceans outside of this order are refer ...

, and other small

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s such as

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, although they also eat squid and small fishes. They can live up to 16 years. Not a lot is known about their predators, though they have been found in the stomachs of albacore tuna and swordfish. Tunas, billfish, and sharks are known to prey on other carangid mackerels, and will presumably also prey on Chilean jack mackerels.''SPRFMO'' (2009
Information describing Chilean jack mackerel ''(Trachurus murphyi)'' fisheries relating to the South Pacific Regional Fishery Management Organisation
Working draft.

Taxonomy and naming

The Chilean jack mackerel was original described in 1920 by the

American American(s) may refer to: * American, something of, from, or related to the United States of America, commonly known as the "United States" or "America" ** Americans, citizens and nationals of the United States of America ** American ancestry, pe ...

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 ...

John Treadwell Nichols John Treadwell Nichols (June 11, 1883 – November 10, 1958) was an American ichthyologist and ornithologist. Life and career Nichols was born in Jamaica Plain, Boston, Massachusetts, the son of Mary Blake (Slocum) and John White Treadwell Nic ...

(1883-1958), in 1996 Konchina ''et al'' treated it as a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are all ...

of the

Pacific jack mackerel The Pacific jack mackerel (''Trachurus symmetricus''), also known as the Californian jack mackerel or simply jack mackerel, is an abundant species of pelagic marine fish in the jack family, Carangidae. It is distributed along the western coast o ...

(''Trachurus symmetricus'') but as a valid subspecies. It is treated as a valid species by most authorities. The specific name honours the American

ornithologist Ornithology is a branch of zoology that concerns the "methodological study and consequent knowledge of birds with all that relates to them." Several aspects of ornithology differ from related disciplines, due partly to the high visibility and th ...

Robert Cushman Murphy The whaling ship, ''Daisy'', which Murphy traveled on to the Antarctic Robert Cushman Murphy (April 29, 1887 – March 20, 1973) was an American ornithologist and Lamont Curator of birds at the American Museum of Natural History. He went on numer ...

(1887-1973), the Curator of Birds at the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

, who collected the type. Murphy collected the type off Central Island,

Chincha Islands The Chincha Islands () are a group of three small islands off the southwest coast of Peru, to which they belong, near the town of Pisco. Since pre-Incan times they were of interest for their extensive guano deposits, but the supplies were mostly ...

, Peru. The Chilean jack mackerel has been recognised as a

sister species In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and t ...

of the

, ''Trachurus symmetricus'', since 2004.Poulin E, Cárdenas L, Hernández CE, Kornfield I and Ojeda FP (2004
"Resolution of the taxonomic status of Chilean and Californian jack mackerels using mitochondrial DNA sequence
''Journal of Fish Biology'', 65 (4): 1160–1164.

Fisheries

Chilean jack mackerels are the most commonly fished species which is not a true

mackerel Mackerel is a common name applied to a number of different species of pelagic fish, mostly from the family Scombridae. They are found in both temperate and tropical seas, mostly living along the coast or offshore in the oceanic environment. ...

. They are caught commercially with surround nets designed for small pelagic

purse seining Seine fishing (or seine-haul fishing; ) is a method of fishing that employs a surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be de ...

, or with midwater trawls, or by

trolling In slang, a troll is a person who posts or makes inflammatory, insincere, digressive, extraneous, or off-topic messages online (such as in social media, a newsgroup, a forum, a chat room, a online video game), or in real life, with the i ...

longlining Longline fishing, or longlining, is a commercial fishing angling technique that uses a long ''main line'' with fish bait, baited fish hook, hooks attached at intervals via short branch lines called ''snoods'' or ''gangions''.< ...

. In the early 1970s, Chilean jack mackerels started flourishing along the west coast of South America, and became important as a commercial species. The mackerel then expanded in a westward movement out into and across the open ocean, eventually reaching the coastal waters around New Zealand and Australia. During 1997 and 1998, a precipitous decline occurred in the catch (see the graph on the right), which can be attributed to changes in the sea surface temperature that accompanied the 1997–98

El Niño El Niño (; ; ) is the warm phase of the El Niño–Southern Oscillation (ENSO) and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific (approximately between the International Date L ...

. On the eastern side of the south Pacific, the Chilean fishery operating mainly within its own EEZ has taken 75% of the global catch over the years. The Peruvian fishery captured 800,000 tonnes in 2001, but overall is an order of magnitude smaller. On the western side of the south Pacific, New Zealand fishes jack mackerel mainly inside their own EEZ, peaking modestly at 25,000 tonnes in 1995–96. From 1978 to 1991, the USSR fishing fleet intensively fished the jack mackerel belt on the

, taking 13 million tonnes. In subsequent years, other distant fishing nations, such as Belize, China, the Netherlands, and the Republic of Korea, have joined Russia fishing the jack mackerel belt, and by 2007, these nations were taking 18% of the global catch. There are fears the fishery may collapse due to

overfishing 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 th ...

. From 2006 to 2011, the

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 ...

of the stocks declined another 63%. Fisheries scientists provisionally estimated in 2011 that to achieve 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 ...

a spawning biomass of about 7.4 million tons was required with a fishing mortality rate of 0.15.Report of the Jack Mackerel Subgroup
''South Pacific Regional Management Organisation'', Annex SWG‐10‐03, Report of the Science Working Group, 19–23 September 2011. If the spawning stock is to rebuild, current catches should probably be less than 390,000 tons. In Chile, a small number of wealthy families own 87% of the jack mackerel harvest. With government agreement, they have been allocated quotas which scientists say are not sustainable.Lords of the fish
''iWatch News'', 25 January 2012. In 2012, a heated dispute developed between Peru and Chile over the fishing of the mackerel.
''The New York Times'', 25 January 2012.Peru and Chile in heated dispute over Jack Mackerel overfishing
''Digital Journal'', 8 February 2012. Attempts have been made since 2006 to empower the South Pacific Regional Management Organisation so it can effectively regulate the jack mackerel industry on the high seas and across national boundaries. Geopolitical rivalries and lack of international cooperation is preventing this. In an interview with the

International Consortium of Investigative Journalists The International Consortium of Investigative Journalists, Inc. (ICIJ), is an independent global network of 280 investigative journalists and over 140 media organizations spanning more than 100 countries. It is based in Washington, D.C. with pe ...

, the French

marine biologist Marine biology is the scientific study of the biology of marine life, organisms in the sea. Given that in biology many scientific classification, phyla, family (biology), families and genera have some species that live in the sea and others th ...

Daniel Pauly Daniel Pauly is a French-born marine biologist, well known for his work in studying human impacts on global fisheries and in 2020 was the most cited fisheries scientist in the world. He is a professor and the project leader of the Sea Around Us ...

compared jack mackerels to

American bison The American bison (''Bison bison'') is a species of bison native to North America. Sometimes colloquially referred to as American buffalo or simply buffalo (a different clade of bovine), it is one of two extant species of bison, alongside the ...

, whose populations also collapsed in the 19th century from overhunting: "This is the last of the buffaloes. When they’re gone, everything will be gone ... This is the closing of the frontier."Jack mackerel, down 90 percent in 20 years in once-rich southern seas, foretells wider global calamity; world’s largest trawlers compete for what is left
''iWatch News'', 25 January 2012.

As food

Chilean jack mackerels are canned or marketed fresh for human consumption; they are a staple food in Africa. They are also processed into

fishmeal Fish meal is a commercial product made from whole wild-caught fish, bycatch and fish by-products to feed farm animals, e.g., pigs, poultry, and farmed fish.R. D. Miles and F. A. Chapman.FA122: The Benefits of Fish Meal in Aquaculture DietsFisherie ...

, which is fed to swine and salmon; five kilograms of jack mackerel are needed to raise one kilogram of farmed salmon.

Similar species

The Chilean jack mackerel looks very much like the

greenback horse mackerel The greenback horse mackerel or greenback scad (''Trachurus declivis'') is a species of jack in the family Carangidae, found around western and southern Australia, and around New Zealand New Zealand ( mi, Aotearoa ) is an island coun ...

''(Trachurus declivis)'' found around Australia and New Zealand. The two species can be distinguished by the number of

gill raker Gill rakers in fish are bony or cartilaginous processes that project from the branchial arch (gill arch) and are involved with suspension feeding tiny prey. They are not to be confused with the gill filaments that compose the fleshy part of the ...

s (''T. declivis'' 50–57, ''T. murphyi'' 51–65) and the number of

scales Scale or scales may refer to: Mathematics * Scale (descriptive set theory), an object defined on a set of points * Scale (ratio), the ratio of a linear dimension of a model to the corresponding dimension of the original * Scale factor, a number w ...

and

scute A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...

s in 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 ...

(''T. declivis'' 81–82, ''T. murphyi'' 89–113). All three species are found schooling around the coast of New Zealand. They are mainly captured using

purse seine Seine fishing (or seine-haul fishing; ) is a method of fishing that employs a surrounding net, called a seine, that hangs vertically in the water with its bottom edge held down by weights and its top edge buoyed by floats. Seine nets can be dep ...

nets, and are managed as though they were one species or stock.Jack Mackerel
NZ Forest and Bird. Retrieved 13 March 2012. In its statistical returns, the

FAO The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

still treats the Pacific jack mackerel as though it were a

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

.''Trachurus murphyi'' (Nichols, 1920)
FAO, Species Fact Sheet. Retrieved 2 March 2012. The capture graph in the fisheries section above is based on the figures supplied by the FAO for the capture of Chilean jack mackerel, and presumably includes also the capture amounts for Pacific jack mackerel.

References

;Sources * Angel A and Ojeda FP (2001
"Structure and trophic organization of subtidal fish assemblages on the northern Chilean coast: the effect of habitat complexity"
''Marine Ecology Progress Series'', 217: 81–91. * Arnaud Bertranda A, Barbierib MA, Hernández C, Gómezc F and Leiva F (2004
"Diel vertical behaviour, predator–prey relationships, and occupation of space by jack mackerel ''(Trachurus murphyi)'' off Chile"
''Journal of Marine Science'', 61 (7): 1105–1112. * Bailey K (1989
"Description and surface distribution of juvenile Peruvian jack mackerel, ''Trachurus murphyi'', Nichols from the subtropical convergence zone of the central South Pacific"
''Fishery Bulletin'', 87: 273–278. * Bertrand A, MA Barbieri, F Gerlotto, F Leiva and J Cordova (2006
"Determinism and plasticity of fish schooling behaviour as exemplified by the South Pacific jack mackerel ''Trachurus murphyi''"
''Marine Ecology Progress Series'', 311: 145–156. * Canales C and R Serra (2008
"Updated Status of the Chilean Jack Mackerel Stock"
FAO: ''South Pacific Regional Management Organisation''
Chilean Jack Workshop
CHJMWS:6.. * Cárdenas L, Silva AX, Magoulas A, Cabezas J, Poulinc E and Ojeda FP (2009
"Genetic population structure in the Chilean jack mackerel, ''Trachurus murphyi'' (Nichols) across the South-eastern Pacific Ocean"
''Fisheries Research'', 100: 109–115. * Cubillos LA, Paramo J, Ruiz P, Nunez S, Sepulveda A (2008
"The spatial structure of the oceanic spawning of jack mackerel ''(Trachurus murphyi)'' off central Chile (1998–2001)"
''Fisheries Research'', 90: 261–270. * Durand NS and Seminario MG (2009
"Status of and trends in the use of small pelagic fish species for reduction fisheries and for human consumption in Peru"
Fisheries and Aquaculture Technical Paper, 518: 325–369. FAO, Rome. * Kawahara S, Uozumi Y and Yamada H (1988
"First record of a carangid fish, ''Trachurus murphyi'' from New Zealand"
''Japanese Journal of Ichthyology'', 35 (2): 212–214. * Ñiquen M and Bouchon M (2004
"Impact of El Niño events on pelagic fisheries in Peruvian waters"
''Oceanography of the Eastern Pacific: Volume III'', 51 (6–9): 563–574. : FAO workshop
Meeting documents
FAO: ''South Pacific Regional Management Organisation''
Chilean Jack Workshop
30 June to 4 July 2008. * Canales C (2008)
"Catch per Unit Effort of Chilean Jack Mackerel ''(Trachurus murphyi)'' of the purse seine fishery off south-central Chile (32° 10′ – 40° 10′ S) 1981–2005
FAO: ''South Pacific Regional Management Organisation'', Chilean Jack Workshop, CHJMWS:10. * Núñez S, S Vásquez, P Ruiz and A Sepúlveda (2008
"Distribution of early developmental stages of jack mackerel in the Southeastern Pacific Ocean"
FAO: ''South Pacific Regional Management Organisation'', Chilean Jack Workshop, CHJMWS:2. * Peña, Hector (2008
"In situ target-strength measurements of Chilean jack mackerel ''(Trachurus symmetricus murphyi)'' collected with a scientific echosounder installed on a fishing vessel"
''ICES J. Mar. Sci.'' 65 (4): 594–604. * Penney A and P Taylor (2008
"An Overview of the New Zealand Jack Mackerel Fishery: Catch Composition, Catch Trends, Seasonality and Length-Frequency Composition"
FAO: ''South Pacific Regional Management Organisation'', Chilean Jack Workshop, CHJMWS:19. * Vasilyev D and A Glubokov (2008
"Preliminary estimation of current state of Chilean Jack Mackerel ''(Trachurus murhyi)'' stock in the high seas of the South East Pacific"
FAO: ''South Pacific Regional Management Organisation'', Chilean Jack Workshop, CHJMWS:22.

External links

Crisis management and jack mackerel fishing in the south Pacific
''Greenpeace briefing'', 25 January 2012. * Nesterov AA and Chu V
"El-Nino and distribution of Jack mackerel ''(Trachurus murphyi)'' in the open part (outside 200-mile zone) of the South-Eastern Pacific Ocean"
''Atlantic Research Institute of Marine Fisheries and Oceanography''.
Outcome of the Third Preparatory Conference of The South Pacific Regional Fisheries Management Organization
''WWF draft statement'', 3 February 2012. {{Taxonbar, from=Q2703257

Chilean jack mackerel The Chilean jack mackerel (''Trachurus murphyi''), sometimes called the Inca scad or Peruvian jack mackerel, is a species of jack mackerel in the genus ''Trachurus'' of the family Carangidae. Since the 1970s, it has become one of the world's mor ...

Fish of Chile Marine fish of Southern Australia Marine fish of New Zealand Western South American coastal fauna Taxa named by John Treadwell Nichols