Pescada-gó
| Pescada-gó | ||||||||||||
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Drawing from Marcus Élieser Bloch's Systema ichthyologiae iconibus CX illustratum |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Macrodon ancylodon | ||||||||||||
| ( Bloch and Schneider , 1801) | ||||||||||||
The pescada-gó ( Macrodon ancylodon ) is a marine fish from the umber fish family . It occurs mainly on the Atlantic coast of South America. This member of the perch-like group has a lot of vernacular names , so it is - as a popular food fish - quite well known in its homeland: the most common is probably Pescada-gó (goete), as it is called in Portuguese in Brazil. Recent genetic studies suggest the existence of at least two populations that may reach species level.
On the Pacific side of South America at about the same latitude (Costa Rica to Ecuador) lives the very similar species Macrodon mordax (Gilbert and Starks, 1904), the "dog-tooth softfish", which is said to also eat squids - which is what you do therefore from ancylodon may also accept. The genus name Macrodon for these croakers comes from H. Schinz 1822. For a long time was understood as " Macrodon " (with J. Müller 1843) but the tetras genus of Hoplias . “ Macrodon asperula ”, on the other hand, is not a fish, but a name for a mussel that is invalid in the nomenclature .
features
The body is stretched, slightly compressed, the profile line almost straight up to D1, the stomach side more arched. The most striking thing about the fish is probably the dentition (the scientific name refers to it: "crooked large tooth"). At the front end of the premaxillary there are two large, inwardly curved pointed teeth; at the front end of the dental a group of similar, but hardly curved, smaller teeth, which are located in front of the former with the mouth closed, but which should not be called "canini" (dog's teeth). The largest teeth are arrowhead-shaped. Laterally on the premaxillary, on the inside of the dental (of the mentioned ones), smaller, less dense (in two rows) standing fangs. This type of dentition can be found, often less clearly, especially in umberfishes with crustacean food. Apparently it is designed in such a way that the fish can use it to grab small crabs that are clinging to mangrove roots, for example, and tear them loose. Similar dentition shapes are already known from primitive Lower Devonian sarcopterygii ( Psarolepis romeri and others, Onychodontiformes , i.e. “claw teeth”); in recent Acanthopterygii but hardly as pronounced - the forms that tear away hard-shelled prey (Sparoids, Blennioids) usually also have pinched teeth in the jawbone, which are known to make up the pharyngeal (pharyngeal) dentition in Sciaenids . The oblique (almost above) mouth is large, the extensions of the gill trap are short, clumsy and few in number.
The “king weakfish” (such an FAO name; also “Jäger-Umber”, acoupa-chasseur for Francophones [translated], for Spanish speakers “King fish”, pescadillo real, in Guyana also bantamary, in Trinidad even German salmon: because of yellowish Oral mucosa) was maximally over 50 cm long, but today hardly reaches this size anymore due to strong adjustment. The color is shadowfish silver with a yellowish tinge at the base of the ventral fins. In young fish, individual scales on the back are dark. No barbels . The posterior margin of the preoperculum is finely serrated. The fish is small and smoothly scaly; the second dorsal fin (which undulatingly serves the propulsion during calm swimming) is almost completely covered with very small scales, similar to the anal fin base. ( Fin formula : D1 X-XI, D2 I / 27-29, A II (weak) / 8-9, C 19.) The caudal fin (C) is pentagonal, the central rays (with the elongated lateral line organ on both sides) are long in juvenile fish moved out. Only the sacculite (the sagitta) is large (for the perception of the species-specific quarr), but thin, the layered lapillus, on the other hand, is rudimentary. The swim bladder has only two simple front attachments - the sound production has apparently not yet been investigated in more detail.
Occurrence
Tropical Atlantic west coast: Trinidad, Venezuela to Mar del Plata (Central Argentina), at 23–28 ° C (therefore less common on the easternmost coasts of Brazil). Mostly over muddy or fine sandy bottom to a depth of 60 m, but usually in the shallow ( littoral ), where he (sociable) hunts crabs ( shrimps , crabs ), molluscs and smaller fish. Gladly in brackish estuaries (especially the young fish) and mangroves . Thanks to this ecology, it can only be caught in small areas with calves or ground nets, but it plays a considerable role in local markets (especially in the southern area of distribution) and must be considered overfished despite the high reproduction rate.
Reproduction
From October to March spawning takes place repeatedly in droves in open water. Sometimes with two activity peaks (November, February). Larger migrations do not take place here (so that the mentioned formation of isolated populations becomes plausible). Sexually mature fish are at least 23 (males) to 30 cm long (females) and usually three (or more) years old (determined maximum age: 7 years).
Individual evidence
- ↑ S. Santos et al. (2002): Estrutura genética de população da pescada-gó, Macrodon ancylodon (Sciaenidae), na costa Atlântica da América do Sul: Grandes divergências genéticas sem mudanças morfológicas.
- ↑ cf. also MI Militelli and GJ Macchi (2004): Spawning and fecundity of king weakfish, Macrodon ancylodon , in the Rio de la Plata estuary, Argentina-Uruguay. J. Mar. Biol. Ass. UK 84: 443-447
Web links
- Pescada-gó on Fishbase.org (English)
- Macrodon ancylodon on [1]