Maclovin , or patagonia [1] [2] ( lat. Eleginops maclovinus ) - marine and brackish-water, bottom, coastal fish from the family of the Patagonian (Eleginopidae) perciformes (Perciformes). The only species of the genus Patagonia ( Eleginops ) and the Patagonian family. It was first described as Eleginus maclovinus in 1830 by the French naturalist Georges Cuvier ( French: Jean Léopold Nicolas Frédéric Cuvier ; 1769-1832). Previously, maclina was included in the Nototheniidae family.
| Maclowina |
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| Scientific classification |
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| No rank : | Bilateral symmetrical |
| Gender: | Patagonia ( Eleginops Gill, 1862 ) |
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| International scientific name |
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Eleginops maclovinus ( Cuvier , 1830) |
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Large fish distributed outside Antarctica off the coast of Patagonia in South America and off the Falkland Islands . In the south of Chile and Argentina, the mackerel (under the name "robo", róbalo) is an object of recreational and sport fishing. Coastal commercial fishing by gill nets and fixed netting is insignificant and is not regulated by special rules.
In the first dorsal fin there are 6–9 flexible spiny rays, in the second dorsal fin 23–27 segmented rays, in the anal fin 11–25 segmented rays, in the pectoral fin 22–25 rays; 4-10 stamens in the upper part of the first branchial arch, 13-19 stamens in the lower part; trunk vertebrae - 19-22, caudal - 23-27.
The body is elongated, fusiform, somewhat compressed laterally, covered with ctenoid and pseudocycloid scales. On the head, the scales are smaller than on the body, the snout and areas under the eyes are bare. The head is small, contained 5 times in body length. The snout is short, bluntly rounded. The eyes are small; the horizontal diameter of the orbit is 6 times the length of the head. The mouth is finite, retractable, relatively small, the posterior edge of the upper jaw is located in front of the front edge of the orbit. Teeth are on the jaws. There are no teeth on the palatine bones and the vomer. The two dorsal fins are separated by a narrow inter-dorsal gap. The first dorsal fin is short, triangular. The second dorsal fin is long, with a higher anterior lobe. The anal fin is similar in shape to the second dorsal fin and somewhat shorter. Caudal fin truncated or slightly notched. The lateral line is one - dorsal (occasionally, the second one can be found - a short medial line) [3] [4] [5] .
The general body color is brownish-gray with a bluish tint, with a darker back and a silver-white or silver-yellowish abdominal part. On the sides of the body, starting from the back, are wide dark stripes that disappear at the ventral part. Dorsal fins dark gray, caudal fin brownish with yellowish hind margin, pectoral fins gray, ventral fins white, anal fin white or brownish-gray.
The species range is characterized as periantarctic, i.e., located outside the Antarctic. Fish are common in temperate and subantarctic climatic zones off the coast of the Argentine and Chilean Patagonia, on Tierra del Fuego in the Strait of Magellan and the Beagle Channel (the southernmost point of distribution), as well as on the Falkland Islands. On the eastern coast of South America, the range is closely connected with the cold coastal Falkland Current , which carries chilled Antarctic waters, and extends north to the latitude of Buenos Aires and the border of Argentina with Uruguay (34 ° S). On the western coast of the continent, the maclinae is known in the zone of the coastal Antarctic Peruvian current up to the latitude of the Chilean port of Valparaiso and the Aconcagua River (33 ° S). Maclovina from continental populations in the extreme south of South America inhabits the littoral to a depth of 40 m, desalinated estuaries , go into the estuaries at high tides, sometimes climbing rivers upstream more than 20 kilometers from the sea coast, as in the Valdivia River (Chile). The Maclowina, which lives near the Falkland Islands, probably leads a more marine way of life and is mainly distributed at depths of more than 40 m [6] [7] [8] [9] [10] .
Large fish: females reach 85–90 cm of total length, males 45–53 cm. Theoretical maximum fish length calculated by the results of determining age and growth is 105 cm [7] [9] .
Marine, euryhaline , eurythermic , bottom-bottom fish. Great resistance to various salinity, due to well-developed osmoregulation , allows the species to easily pass from sea water with a salinity of about 30–34 ppm to desalinated water of estuaries and estuaries with salinity of about 9–10 ‰, as well as fresh water rivers and return back to marine environment. Omnivorous fish, mainly benthophages with a tendency to predation . They feed mainly on a variety of bottom and bottom invertebrate organisms - polychaetes , crustaceans (mainly gammarids ), mollusks (bivalves and gastropods), as well as plant foods (algae), insects and small fish. Young fish 30–160 mm long feed almost exclusively on plankton [6] [10] [11] [8] [12] [10] .
According to the type of breeding, unlike other notothenoid fish, they are protandric hermaphrodites , in which the young maturing for the first time spawning individuals are males, and the fish of older age groups are females. Fishes function as males between the ages of two and seven years with a total length of 16–19 to 45 cm, females mature at the age of 3–8 years with a total length of 28–58 cm. In the south of Patagonia, off the Chilean coast, all fish are longer than 46 cm are females, on the Falkland Islands, females are all fish with a total length of more than 54 cm. The average calculated fish length, at which 50% of all individuals undergo gender reversal, varies from 30 to 36 cm in different populations [13] [7] [9 ] ] .
Spawning in southern Chile (probably one-time) occurs in late winter - early spring (Southern Hemisphere), with a peak in September, exclusively in the desalinated waters of estuaries. Experiments in aquaculture to obtain reproductive products and incubation of eggs showed that the main stimulant for the maturation of fish is low salinity water - about 12.3 ‰ and a low temperature of about 8-10 ° C. Females lay eggs in narrow depressions on the sandy bottom of coastal shallows formed by the erosive activity of waves. In the Falkland Islands, fish spawn mainly in the spring and, probably, their spawning grounds are not associated with estuary zones, as in continental populations. The caviar is small - with a diameter of about 1.0-1.2 mm and, as shown for the Falkland Islands, pelagic. Fertility is quite large in comparison with other notothenoid ones. According to various sources, the absolute fecundity in the southern continental populations ranges from 352,195-550,000 eggs, the relative fecundity is about 284-330 eggs / g. In fish from the Falkland Islands, long batch spawning is assumed at depths of 30 to 100 m and much more fertility is shown: absolute - 1.1–7.3 million eggs, relative - 331–1334 eggs / g (average 796). Embryonic development at medium temperatures from 9.3 to 11.8 ° C lasts from 117 to 72 hours. Postembryonic development of larvae at an average temperature of about 10 ° C lasts about 10 days [11] [9] [7] [14] .
The maximum life span determined for a female with a total length of 79 cm is 10 years [9] .