Chilean jack mackerel

Last updated

Chilean jack mackerel
Chilean purse seine.jpg
A school of about 400 tons of Chilean jack mackerel encircled by a purse seine
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Carangiformes
Family: Carangidae
Genus: Trachurus
Species:
T. murphyi
Binomial name
Trachurus murphyi
Nichols, 1920
Trachurus murphyi range map.jpg
  Estimated distribution
Synonyms [2]
  • Caranx peruanus Tschudi, 1846
  • Trachurus peruanus(Tschudi, 1846)

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. [3] Since the 1970s, it has become one of the world's more important commercial fish species. [4] High volumes have been harvested, but the fishery may now be in danger of collapsing. [5] [6]

Contents

Description

Chilean jack mackerels are commonly 45 cm (18 in) long, though they can grow to 70 cm (28 in). 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 is much longer than the first. The pectoral fins are long and pointed. The origin of the pelvic fins is below the bottom point of attachment of the pectorals. The anal fin 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. [4] [2]

Distribution and habitat

The Chilean jack mackerel is an epipelagic fish that swims in schools 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. [4] 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. [4] [2] In 1993, Elizarov et al. referred to this band on the high seas as the "jack mackerel belt". [7] 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". [7] [8] Chilean jack mackerel normally spawn in summer. Their eggs are pelagic, that is, they float free in the open sea. [4]

Not enough data are available to know for sure the Chilean jack mackerel stock structure. [1] However, four separate stocks have been proposed: "a Chilean stock which is a straddling stock with respect to the high seas; 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." [8]

Ecology

Chilean jack mackerels mainly eat fish larvae, shrimp, and other small crustaceans such as copepods, although they also eat squid and small fishes. They can live up to 16 years. [4] 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. [8]

Taxonomy and naming

The Chilean jack mackerel was original described in 1920 by the American ichthyologist John Treadwell Nichols (1883-1958), in 1996 Konchina et al treated it as a synonym of the Pacific jack mackerel (Trachurus symmetricus) but as a valid subspecies. It is treated as a valid species by most authorities. [9] The specific name honours the American ornithologist Robert Cushman Murphy (1887-1973), the Curator of Birds at the American Museum of Natural History, who collected the type. [10] Murphy collected the type off Central Island, Chincha Islands, Peru. [9]

The Chilean jack mackerel has been recognised as a sister species of the Pacific jack mackerel, Trachurus symmetricus, since 2004. [3] [2] [1] [11]

Fisheries

Capture of Chilean jack macherel in tonnes 1970 - 2022.png
Capture of Chilean jack mackerel in tonnes from 1970 to 2022 [12]
Movement of surface waters during El Nino.jpg
During an El Niño, such as occurred in 1997–98, weaker winds fail to draw the cold, nutrient-rich waters up to the surface, resulting in a fall in the jack mackerel abundance.

Chilean jack mackerels are the most commonly fished species which is not a true mackerel. They are caught commercially with surround nets designed for small pelagic purse seining, or with midwater trawls, or by trolling or longlining. [4] [8] [13]

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. [8] 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. [14]

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. [8] 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 high seas, 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. [8]

There are fears the fishery may collapse due to overfishing. [15] From 2006 to 2011, the biomass of the stocks declined another 63%. [6] Fisheries scientists provisionally estimated in 2011 that to achieve the maximum sustainable yield a spawning biomass of about 7.4 million tons was required with a fishing mortality rate of 0.15. [16] If the spawning stock is to rebuild, current catches should probably be less than 390,000 tons. [16]

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) [17]

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. [18] In 2012, a heated dispute developed between Peru and Chile over the fishing of the mackerel. [5] [19] 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. [6] In an interview with the International Consortium of Investigative Journalists, the French marine biologist Daniel Pauly compared jack mackerels to American bison, 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." [6]

As food

Chilean jack mackerels are canned or marketed fresh for human consumption; [4] they are a staple food in Africa. They are also processed into fishmeal, which is fed to swine and salmon; five kilograms of jack mackerel are needed to raise one kilogram of farmed salmon. [6]

Similar species

Similar species
Trachurus symmetricus.jpg
The Pacific jack mackerel is a sister species to the Chilean jack mackerel [11]
Trachurus declivis drawing.jpg
The greenback horse mackerel is very similar in appearance

The Chilean jack mackerel looks very much like the greenback horse mackerel (Trachurus declivis) found around Australia and New Zealand. The two species can be distinguished by the number of gill rakers (T. declivis 50–57, T. murphyi 51–65) and the number of scales and scutes in the lateral line (T. declivis 81–82, T. murphyi 89–113). [4]

All three species are found schooling around the coast of New Zealand. They are mainly captured using purse seine nets, and are managed as though they were one species or stock. [20]

In its statistical returns, the FAO still treats the Pacific jack mackerel as though it were a subspecies. [4] 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.

Related Research Articles

<span class="mw-page-title-main">Mackerel</span> Pelagic fish

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.

<span class="mw-page-title-main">Hake</span> Family of fishes

Hake is the common name for fish in the Merlucciidae family of the northern and southern oceans and the Phycidae family of the northern oceans. Hake is a commercially important fish in the same taxonomic order, Gadiformes, as cod and haddock.

<span class="mw-page-title-main">Overfishing</span> Removal of a species of fish from water at a rate that the species cannot replenish

Overfishing is the removal of a species of fish from a body of water at a rate greater than that the species can replenish its population naturally, resulting in the species becoming increasingly underpopulated in that area. Overfishing can occur in water bodies of any sizes, such as ponds, wetlands, rivers, lakes or oceans, and can result in resource depletion, reduced biological growth rates and low biomass levels. Sustained overfishing can lead to critical depensation, where the fish population is no longer able to sustain itself. Some forms of overfishing, such as the overfishing of sharks, has led to the upset of entire marine ecosystems. Types of overfishing include: growth overfishing, recruitment overfishing, ecosystem overfishing.

<span class="mw-page-title-main">Fisheries management</span> Regulation of fishing

The goal of fisheries management is to produce sustainable biological, environmental and socioeconomic benefits from renewable aquatic resources. Wild fisheries are classified as renewable when the organisms of interest produce an annual biological surplus that with judicious management can be harvested without reducing future productivity. Fishery management employs activities that protect fishery resources so sustainable exploitation is possible, drawing on fisheries science and possibly including the precautionary principle.

<span class="mw-page-title-main">Orange roughy</span> Species of fish

The orange roughy, also known as the red roughy, slimehead and deep sea perch, is a relatively large deep-sea fish belonging to the slimehead family (Trachichthyidae). The UK Marine Conservation Society has categorized orange roughy as "vulnerable to exploitation". It is found in 3 to 9 °C, deep waters of the Western Pacific Ocean, eastern Atlantic Ocean, Indo-Pacific, and in the eastern Pacific off Chile. The orange roughy is notable for its extraordinary lifespan, attaining over 200 years. It is important to commercial deep-trawl fisheries. The fish is a bright, brick-red color, fading to a yellowish-orange after death.

<span class="mw-page-title-main">Humboldt Current</span> Current of the Pacific Ocean

The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America. It is an eastern boundary current flowing in the direction of the equator, and extends 500–1,000 km (310–620 mi) offshore. The Humboldt Current is named after the German naturalist Alexander von Humboldt even though it was discovered by José de Acosta 250 years before Humboldt. In 1846, von Humboldt reported measurements of the cold-water current in his book Cosmos.

<span class="mw-page-title-main">Fish stocks</span> Semi-discrete subpopulations of a particular species of fish

Fish stocks are subpopulations of a particular species of fish, for which intrinsic parameters are traditionally regarded as the significant factors determining the stock's population dynamics, while extrinsic factors are traditionally ignored.

Horse mackerel is a vague vernacular term for a range of species of fish throughout the English-speaking world. It is commonly applied to pelagic fishes, especially of the Carangidae family, most commonly those of the genera Trachurus or Caranx. Species known as "horse mackerel" in one English dialect or another include:

<span class="mw-page-title-main">Atlantic horse mackerel</span> Species of fish

The Atlantic horse mackerel, also known as the European horse mackerel or common scad, is a species of jack mackerel in the family Carangidae, which includes the jacks, pompanos and trevallies. It is found in the eastern Atlantic Ocean off Europe and Africa and into the south-eastern Indian Ocean. It is an important species in commercial fisheries and is listed as a Vulnerable species on The IUCN Red List of Threatened Species.

<span class="mw-page-title-main">Pacific jack mackerel</span> Species of fish

The Pacific jack mackerel, 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 of North America, ranging from Alaska in the north to the Gulf of California in the south, inhabiting both offshore and inshore environments. The Pacific jack mackerel is a moderately large fish, growing to a maximum recorded length of 81 cm, although commonly seen below 55 cm. It is very similar in appearance to other members of its genus, Trachurus, especially T. murphyi, which was once thought to be a subspecies of T. symmetricus, and inhabits waters further south. Pacific jack mackerel travel in large schools, ranging up to 600 miles offshore and to depths of 400 m, generally moving through the upper part of the water column.

<i>Thyrsites</i> Genus of fish

Thyrsites atun, known as the snoek in South Africa and as the barracouta in Australasia, is a long, thin species of snake mackerel found in the seas of the Southern Hemisphere, and a popular food fish in South Africa, particularly along the west and southwest coast. Despite its Australasian name, it is not closely related to the barracuda.

<span class="mw-page-title-main">Blue mackerel</span> Species of fish

The blue mackerel, also called Japanese mackerel, Pacific mackerel, slimy mackerel or spotted chub mackerel, is a fish of the family Scombridae, found in tropical and subtropical waters of the Pacific Ocean from Japan south to Australia and New Zealand, in the eastern Pacific, and the Indo-West Pacific: the Red Sea, the Persian Gulf, the Gulf of Oman and the Gulf of Aden, in surface waters down to 200 m (660 ft). In Japanese, it is known as goma saba. It typically reaches 30 cm (12 in) in length and 1.4 kg (3.1 lb) in weight.

<span class="mw-page-title-main">Greenback horse mackerel</span> Species of fish

The greenback horse mackerel or greenback scad is a species of jack in the family Carangidae, found around western and southern Australia, and around New Zealand, from the surface to depths of 460 m. Its length is up to 64 cm.

The South East Atlantic Fisheries Organisation (SEAFO) is an organization that maintains controls over fishing and fishing related acts in the Southeastern Atlantic Ocean.

<span class="mw-page-title-main">Fishing industry in the United States</span>

As with other countries, the 200 nautical miles (370 km) exclusive economic zone (EEZ) off the coast of the United States gives its fishing industry special fishing rights. It covers 11.4 million square kilometres, which is the second largest zone in the world, exceeding the land area of the United States.

<span class="mw-page-title-main">False scad</span> Species of fish

The false scad, also known as the spotfin scad, ten-finned horse mackerel and yellow horse mackerel, is a species of medium-sized marine fish classified in the jack family Carangidae. The false scad is distributed throughout the tropical and temperate waters of the eastern Atlantic Ocean from Namibia in the south to Spain and throughout most of the Mediterranean in the north. The species has an atypical body form compared to other species of Caranx, and can be distinguished from these on its elongate 'scad-like' body shape alone. Distinguishing the species from members of Decapterus and Trachurus is more difficult, requiring detailed anatomical analysis. The false scad is known to grow to a length of 60 cm and a weight of 1 kg. The species lives both pelagically and demersally in continental shelf waters, ranging from depths of 15 to 200 m. It is a predatory fish, taking small fishes, crustaceans including euphausiids and shrimps, and cephalopods as its main prey, with significant dietary shifts as it ages. The false scad reaches sexual maturity at 2 years of age, with spawning occurring between April and July in shallow inshore waters, where the juveniles remain. The species is of major importance to fisheries throughout its range, but particularly from Morocco to Senegal, with annual catches ranging from 500 to 19000 t. The species is caught using trawls, seine nets and gill nets and sold fresh, frozen or salted.

<span class="mw-page-title-main">Cape horse mackerel</span> Species of fish

The Cape horse mackerel is a mackerel-like species in the family Carangidae. It is a pelagic species of the south eastern Atlantic Ocean which is a target of fisheries, mainly as bycatch.

<span class="mw-page-title-main">Japanese jack mackerel</span> Species of fish

The Japanese jack mackerel, also known as the Japanese horse mackerel or Japanese scad, is a species named after its resemblance to mackerel but which is in the family Carangidae, the jacks, pompanos, trevallies and scads. Their maximum reported length is 50 cm (20 in) with a common length of 35 cm (14 in). They have a maximum reported weight of 0.66 kg (1.5 lb) and a maximum reported age of 12 years. They are found around the coast of Japan, except Okinawa Island, usually on sandy bottoms of 50–275 m (164–902 ft) deep. They feed mainly on small crustaceans such as copepods, as well as shrimp and small fish. They are similar to the yellowtail horse mackerel around New Zealand and Australia, apart from having more gill rakers and larger eyes.

<span class="mw-page-title-main">Yellowstripe scad</span> Species of fish

The yellowstripe scad, also known as the yellowstripe trevally, yellow-banded trevally, smooth-tailed trevally, slender-scaled trevally and slender trevally, is a species of small inshore fish in the jack and horse mackerel family Carangidae, and the only member of the genus Selaroides. The yellowstripe trevally is distributed throughout the tropical waters of the Indo-West Pacific region, ranging from the Persian Gulf in the west to Vanuatu and New Caledonia in the east. The species is distinguished by its prominent lateral yellow band, and differs from the scads of the genus Selar in having a smaller eye and different dentition. Although the yellowstripe scad reaches a maximum recorded length of 22 cm, it is normally encountered at sizes less than 15 cm. Phylogenetic studies indicate the yellowstripe scad is closely related to the scads of the genus Selar, although its exact placement in the family Carangidae is less well agreed upon.

<span class="mw-page-title-main">Arabian scad</span> Species of fish

The Arabian scad is a species of jack mackerel from the family Carangidae which is found in the Western Indian Ocean.

References

  1. 1 2 3 Smith-Vaniz, B.; Robertson, R.; Dominici-Arosemena, A. (2010). "Trachurus murphyi". IUCN Red List of Threatened Species . 2010: e.T183965A8207652. doi: 10.2305/IUCN.UK.2010-3.RLTS.T183965A8207652.en . Retrieved 19 November 2021.
  2. 1 2 3 4 Froese, Rainer; Pauly, Daniel (eds.) (2019). "Trachurus murphyi" in FishBase . August 2019 version.
  3. 1 2 "Trachurus murphyi". Integrated Taxonomic Information System . Retrieved 8 March 2012.
  4. 1 2 3 4 5 6 7 8 9 10 Trachurus murphyi (Nichols, 1920) FAO, Species Fact Sheet. Retrieved 2 March 2012.
  5. 1 2 In mackerel's plunder, hints of epic fish collapse The New York Times, 25 January 2012.
  6. 1 2 3 4 5 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 Archived 2012-03-18 at the Wayback Machine iWatch News, 25 January 2012.
  7. 1 2 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.
  8. 1 2 3 4 5 6 7 SPRFMO (2009) Information describing Chilean jack mackerel (Trachurus murphyi) fisheries relating to the South Pacific Regional Fishery Management Organisation Archived 2013-02-27 at the Wayback Machine Working draft.
  9. 1 2 Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Trachurus murphyi". Catalog of Fishes . California Academy of Sciences . Retrieved 7 December 2019.
  10. Christopher Scharpf; Kenneth J. Lazara (10 August 2019). "Order CARANGIFORMES (Jacks)". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 7 December 2019.
  11. 1 2 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. doi : 10.1111/j.0022-1112.2004.00514.x
  12. https://firms.fao.org/firms/resource/13884/en
  13. Surrounding nets Fishing Gear Types, FAO, Rome. Retrieved 13 March 2012.
  14. Arcos DF, Cubillos LA and Núñez SP (2001) "The jack mackerel fishery and El Niño 1997–98 effects off Chile" Progress In Oceanography, 49 (1–4): 597–617.
  15. Preventing the collapse of one of the world’s largest fisheries Digital Journal, 14 February 2012.
  16. 1 2 Report of the Jack Mackerel Subgroup Archived 2013-02-27 at the Wayback Machine South Pacific Regional Management Organisation, Annex SWG‐10‐03, Report of the Science Working Group, 19–23 September 2011.
  17. https://firms.fao.org/firms/resource/13884/en
  18. Lords of the fish Archived 2012-03-20 at the Wayback Machine iWatch News, 25 January 2012.
  19. Peru and Chile in heated dispute over Jack Mackerel overfishing Digital Journal, 8 February 2012.
  20. Jack Mackerel Archived 2012-03-05 at the Wayback Machine NZ Forest and Bird. Retrieved 13 March 2012.
Sources
FAO workshop