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

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

in the genus '' Trachurus'' of the family

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

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

dorsal fin A dorsal fin is a fin on the back of most marine and freshwater vertebrates. Dorsal fins have evolved independently several times through convergent evolution adapting to marine environments, so the fins are not all homologous. They are found ...

is much longer than the first. The

pectoral fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish aquatic locomotion, swim. Apart from the tail or caudal fin, fish fins have no direct connection with the vertebral column ...

s are long and pointed. The origin of the

pelvic fin Pelvic fins or ventral fins are paired fins located on the ventral (belly) surface of fish, and are the lower of the only two sets of paired fins (the other being the laterally positioned pectoral fins). The pelvic fins are homologous to the hi ...

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

anal fin Fins are moving appendages protruding from the body of fish that interact with water to generate thrust and help the fish swim. Apart from the tail or caudal fin, fish fins have no direct connection with the back bone and are supported o ...

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 live on or near the bottom, and reef fish that are associated with coral reefs. ...

that swims in

schools A school is the educational institution (and, in the case of in-person learning, the building) designed to provide learning environments for the teaching of students, usually under the direction of teachers. Most countries have systems of ...

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: * Spawning, 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: Armageddon' ...

in summer. Their eggs are

pelagic The pelagic zone consists of the water column of the open ocean and can be further divided into regions by depth. The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or water column between the sur ...

, 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 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

EEZ An exclusive economic zone (EEZ), as prescribed by the 1982 United Nations Convention on the Law of the Sea, is an area of the sea in which a sovereign state has exclusive rights regarding the exploration and use of marine natural resource, reso ...

s."

Ecology

Chilean jack mackerels mainly eat

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

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 ...

, and other small

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 ...

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 (living in the water column), some are benthos, benthic (living on the sedimen ...

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

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, 35,800 species of fish had been described as of March 2 ...

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

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

synonym A synonym is a word, morpheme, or phrase that means precisely 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 a ...

of the Pacific jack mackerel (''Trachurus symmetricus'') but as a valid subspecies. It is treated as a valid species by most authorities. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

honours the American

ornithologist Ornithology, from Ancient Greek ὄρνις (''órnis''), meaning "bird", and -logy from λόγος (''lógos''), meaning "study", is a branch of zoology dedicated to the study of birds. Several aspects of ornithology differ from related discip ...

Robert Cushman Murphy file:The American Museum journal (c1900-(1918)) (18156963552).jpg, 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 ...

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

American Museum of Natural History The American Museum of Natural History (AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. Located in Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 21 interconn ...

, who collected the

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

. Murphy collected the type off Central Island, Chincha Islands, 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 ...

of the Pacific jack mackerel, ''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, or with midwater trawls, or by

trolling In slang, a troll is a person who posts deliberately offensive or provocative messages online (such as in social media, a newsgroup, a internet forum, forum, a chat room, an Multiplayer video game, online video game) or who performs similar be ...

or longlining. 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 Sea surface temperature (or ocean surface temperature) is the ocean temperature, temperature of ocean water close to the surface. The exact meaning of ''surface'' varies in the literature and in practice. It is usually between and below the sea ...

that accompanied the 1997–98

El Niño EL, El or el may refer to: Arts and entertainment Fictional entities * El, a character from the manga series ''Shugo Chara!'' by Peach-Pit * Eleven (''Stranger Things'') (El), a fictional character in the TV series ''Stranger Things'' * El, fami ...

. On the eastern side of the south Pacific, the Chilean fishery operating mainly within its own

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 stocks, fish stock), resu ...

. From 2006 to 2011, the

biomass Biomass is a term used in several contexts: in the context of ecology it means living organisms, and in the context of bioenergy it means matter from recently living (but now dead) organisms. In the latter context, there are variations in how ...

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 o ...

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. New data and indicators on the status of the jack mackerel stock suggest that conditions evaluated in detail from the last benchmark assessment (2022) are relatively unchanged. The population trend is estimated to be increasing. The indications of stock improvement (higher abundance observed in the acoustic survey in the northern part of Chile, better catch rates apparent in all fisheries for which data are available, and increase in average age in the Chilean fisheries) drive the increase. Near term spawning biomass is expected to increase from the 2018 estimate of 4.8 million t to 5.6 million t in 2019 (with approximate 90% confidence bounds of 4.5 – 7.0 million t) 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 ...

, the French

marine biologist Marine biology is the scientific study of the biology of marine life, organisms that inhabit the sea. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology clas ...

Daniel Pauly Dr. Sir Daniel Pauly is a France, 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 ...

compared jack mackerels to

American bison The American bison (''Bison bison''; : ''bison''), commonly known as the American buffalo, or simply buffalo (not to be confused with Bubalina, true buffalo), is a species of bison that is endemic species, endemic (or native) to North America. ...

, 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 a way to protect the migrating mackerel, in 2013 the countries Chile, Peru, New Zealand and Australia, as well as six more agreed to form the " South Pacific Regional Fishing Management Organisation (RFMO)". The act has led to significant improvements; in 2019 the species had already recovered to a degree similar to the population in the 1990s.

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 (sometimes spelled fishmeal) is a commercial product made from whole wild-caught fish, bycatch, and fish by-products to feed farm animals, such as pigs, poultry, and farmed fish.R. D. Miles and F. A. Chapman.FA122: The Benefits of Fish ...

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

farmed salmon The aquaculture of salmonids is the fish farming, farming and harvesting of salmonid fish under controlled conditions for both commercial and recreational purposes. Salmonids (particularly salmon and rainbow trout), along with carp and tilapia, a ...

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 Carangidae, jack in the family Carangidae, found around western and southern Australia, and around New Zealand, from the surface to depths of 460 m. Its leng ...

''(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 th ...

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 ...

and

scute A scute () or scutum (Latin: ''scutum''; plural: ''scuta'' "Scutum (shield), 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 Bird anatomy#Scales, birds. The ter ...

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 epithelia ...

(''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 de ...

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) is a List of specialized agencies of the United Nations, specialized agency of the United Nations that leads international efforts to defeat hunger and improve nutrition ...

still treats the Pacific jack mackerel as though it were a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

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