SPECIES: PEACOCK BASS

THE PEACOCK BASS

There are more than 15 described species of Peacock Bass, (Cichla genus) in South America, and these family of fish has a very complex reproductive cicle and their feeding adaptive behavior are remarkable when compared with other Amazon fish species. The largest and most powerfull specie is the Cichla Temensis. These fish can reach up to 30 pounds, and they are found in entire Negro River Basin. There are two distinctive color phases for the Temensis species. One is the speckled color, (“Paca” in Brazil) found in all Temensis species at non-spawing periods and the other famous one is the “Assu” (or Three Bar) color; typical of spawning phase period and well known by the three vertical black stripes. These colors changing process is gradual and generate one of the most amazing fish color variety an angler can see. The Temensis peacock bass are extremely territorial and during spawning periods they can stay for weeks in same nest area protecting their hatch. Their behavior can turn very aggressive when other predators try to attack their juveline nursery areas.

Scientific nomenclature: Cichla Schneider, 1801; Tucunaré-açu/paca: Cichla temensis (Humboldt, 1821); Tucunaré-borboleta/botão: Cichla orinocensis (Humboldt, 1821); Yellow tucunare/açuzinho: Cichla monoculus (Spix & Agassiz, 1831).

Common names: peacock bass (USA), tucunaré (Brazil), pavón (Colombia and Venezuela), kounanni (French Guiana), toukounaré (French Guiana), tucunari (Peru), lukanani (Guiana).

Fifteen species are currently acknowledged as belonging to the genus Cichla, according to a review of the genus by Kullander and Ferreira (2006). Of these species, only C. intermedia Machado-Allison, 1971, is not distributed in the Brazilian territory, being restricted to the Orenoco basin and to the Cassiquiare channel, in Colombia and Venezuela. Two other species are to be found in the Orenoco basin, as well as in Brazil: C. temensis and C. orinocensis. Two species are also found in small drainage areas in the Guianas which flow directly into the Atlantic Ocean: C. ocellaris and C. monoculus.

FISH BIOLOGY

The peacock bass species (Cichla spp.) are among the most important South American fish used as food and in the practice of sport fishing. Some easily observable features are used in the identification of the genus: the shape of the dorsal fin, which is unique among South American cichlids, and the presence of a conspicuous eye-like spot at the base of the caudal fin, which mimics a false eye . The Peacock Bass have an elongated and moderately high body, which may be three to five times its length. They are laterally compressed, with a convex dorsal and a straight abdominal profile.

They have a large head, with a length in the range of 28.5 per cent to 33 per cent total length; the head length is six to ten times larger than the diameter of the large eyes; large terminal, prognathous mouth (with a more prominent lower jaw) and an exposed jaw, in low position, which surpasses in size the length of the rest of the head; the ascendant process of the pre-jaw extends back from the nose, but does not reach the anterior margin of the eye orbit; the teeth are small, curved, simple, pointed, densely set in well defined bands and set in tooth plates in the pre-maxillary and dental bones; the posterior border of the pre-operculum is smooth; ctenoid scales cover most of the body.




The shape of the dorsal fin sets these fish apart from the other species of the family Cichlidae in this part of South America, where cichlids display the largest variety with respect to body shapes. The tail fin is always truncated; in some species its top border shows an acute angle, whereas the lower border is rounded. The general coloring of the background may vary substantially along the year, becoming more intense during the breeding season. Bands or rounded spots, or a black longitudinal stripe, are seen in the flanks of juvenile and adult specimens, and serve to distinguish different species.

The back is slightly darker, displaying grey hues, black, dark brown, brown, greenish or bluish tones. The flanks are yellowish, greenish, greyish, bluish, orange or copper-colored. The lower mouth region, under the opercula and over the branchiostegal rays, may be orange or red hued, with more intense coloration during the breeding season.

A well defined and peculiar eye-like spot lies at the base of the tail, right at the edge of the caudal fin. Great doubts persist as to whether the variety of açu and paca present in the Negro river basin belongs to the same species or not. Recently published genetic studies have revealed that these forms belong to the same species: C. temensis; other species of tucunare also display variations in the paca form: C. piquiti, C. pinima and C. vazzoleri.



SIZES & WEIGHTS

The largest species of peacock bass, is the Cichla temensis, and reaches up to slightly more than one meter in length and 12 kilos, but, according to some accounts by riverside dwellers of the Negro river, this species may reach, and rarely exceed, the 16 kilo limit. Other species also reach great sizes, exceeding 90 centimeters and 10 kilos, such as Cichla pinima and Cichla vazzoleri.

The peacock bass preferentially inhabit lentic environments, i.e., the more still waters of lakes and lagoons, but also river margins, in inlets or lagoons connected to rivers by wide mouths, in the backwaters and river channels, as well as the shallow areas with abundant structures (tree trunks and branches, vegetation on the sides and rocks).

Some species (C. melaniae, C. temensis and C. piquiti) may also occur in lotic and semilotic environments, such as river rapids and stretches with quick flowing water, generally remaining in areas which are away from the current flow, in more sheltered areas, normally behind rocks, tree trunks or branches.

Variations in the water level in the Amazon rivers influence the reproductive process of the fish and their access to food resources. In their natural environments, larger fish from species that may attain larger sizes, such as the Temensis species, undertake displacement across larger distances, as compared to smaller specimens and species, such as the butterfly species (C. orinocensis).

FEEDING BEHAVIOR

They prey on other fish, eating a large variety of species, including their own; they may also prey on shrimps, insects and other arthropods during their juvenile stage; occasionally, some adult individuals may eat arthropods. The species of Cichla exploit the resources which are available to them in the environment, displaying an opportunistic behavior.

In their natural, non-modified, environments, tucunare fish eat a wide range of prey, especially members of Characiformes and Siluriformes, and are also cannibalistic. Some species of tucunare temporarily associate themselves with ray fish, which attract other fish during their feeding activity, as they rake and shake the substratum with their bodies.

Their activity is boosted during days with higher temperatures and higher light intensity, which are concentrated during the period between 9am and 3pm. The biotic factors which most influence the number of tucunare are temperature variations, rainfall, as well as the variation and duration of the photoperiod.

SPAWNING

Spawning of peacock bass is performed in a straggled fashion, with its peak at the end of the dry season and the onset of the rainy season (floods), although they are able to reproduce along the whole year. They do not undergo reproductive migrations and they tend to their young.

Fertility rates are variable, with 1,500 to 15,000 oocytes per spawning event; fertility rates for two species of Cichla introduced at the Volta Grande reservoir are in the range of 13,769 to 17,987 oocytes. Both the spawn and the recently hatched larvae adhere to the substrate. The fish dig nests at the bottom of river banks, where they transfer the newly hatched fry, depositing them on the surface of tree trunks or rocks.