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Oreochromis variabilis (Boulenger, 1906)

Victoria tilapia
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Oreochromis variabilis
Male picture by Loiselle, P.V.

分類 / Names 俗名 | 同種異名 | Catalog of Fishes(, ) | ITIS | CoL | WoRMS | Cloffa

Teleostei > Cichliformes (Cichlids, convict blennies) 鱸形目 (Cichlids, convict blennies) > Cichlidae (Cichlids) 慈鯛科魚類 (Cichlids) > Pseudocrenilabrinae
Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch (Ref. 45335).
More on author: Boulenger.

Environment: milieu / climate zone / depth range / distribution range 生態學

; 淡水 底中水層性; 深度上下限 4 - 49 m. 熱帶; 23°C - 28°C (Ref. 3)

分布 國家 | FAO區域 | 生態系 | 發現紀錄 | Point map | 簡介 | Faunafri

Africa: Lake Victoria and its affluent rivers (Ref. 5166, 34290, 118630, 118638), Victoria Nile above Murchison Falls (Ref. 5166) and Lakes Kyoga, Kwania and Salisbury (Ref. 5166), but strongly declining or disappeared in many areas (Ref. 52331), apparently replaced by Oreochromis niloticus (Ref. 34290). Introduced into several dams in Lake Victoria region (Ref. 118638).
非洲: 維多利亞湖與它的支流; 在 Murchison 秋天上面的維多利亞尼羅河; 湖 Kyoga 湖, Kwania 與索爾斯堡。

大小 / 重量 / 年齡

Maturity: Lm ?  range ? - ? cm
Max length : 30.0 cm SL 雄魚/尚未辨別雌雄; (Ref. 34290)

簡短描述 檢索表 | 型態特徵 | 形態測量圖

背棘 (總數) : 16 - 18; 背的軟條 (總數) : 10 - 12; 臀棘: 3; 臀鰭軟條: 9 - 11; 脊椎骨: 29 - 31. Diagnosis: Large bodied tilapiine cichlid; females and unripe males have a grey/green body and fins with 6-7 dark vertical bars on the flank; ripening males with yellowish chin, and notable bright red/orange margins to the dorsal and caudal fins; fully ripe males are black with a blue sheen on the head, bright red/orange margins to the dorsal and caudal fins and a long, branched whitish or yellow genital tassel (Ref. 118638). The breeding male of Oreochromis variabilis is distinguished from O. niloticus and O. esculentus by the intense orange to scarlet colour of the margin of the dorsal fin and the long, tasselled genital papilla, as well as by the general body colour; the orange dorsal margin is present also in grown females and non-breeding males, though narrower and less brilliant (Ref. 2). Other distinguishing characters are: the tilapia-mark is absent in young longer than 15 mm standard length, whereas in O. esculentus it is conspicuous and with a clear ring up to about 70 mm standard length and may still be detected up to 170 mm; the profile usually has a convexity immediately before the eye; there are usually two rows of scales on the cheek in contrast to usually three in O. esculentus; in half-grown and full-grown fishes there are 4-7 series of teeth in the jaws, 3-5 in O. esculentus; the ratio depth of preorbital to length of head is more than 1/5 in O. variabilis, 1/5 or less in O. esculentus; longer gill-rakers; and whereas O. esculentus does not mount beyond the estuaries, O. variabilis enters rivers from the lake (Ref. 2). Oreochromis variabilis differs from both O. malagarasi and O. upembae, its nearest relatives, in the suppression in most phases of blotches on the flanks, in the body colour of mature males, which is blue-grey to blue-black vs. yellowish in O. upembae, in the shape of the profile, which in O. malagarasi and O. upembae lacks the 'bump' before the eye, a lower modal number of soft dorsal and anal rays, and a higher modal number of vertebrae; Oreochromis upembae also differs from O. variabilis in having usually narrow vertical stripes on the caudal fin (Ref. 2).
背鰭的邊緣橘色的在雌性與非繁殖期的雄性中; 密集橘色的對在繁殖期的雄性中的深紅色。 在眼正前方的輪廓凸狀。 通常在頰上的 2個列的鱗片。 尾部的不很重地覆有鱗片的。 保存的標本時常在梗的頂端上顯示 2-3個模糊的黑色側面中央的斑塊與一。 體色灰色的-綠色.(參考文獻 4967)

生物學特性     字彙 (例如 epibenthic)

Adults feed predominantly on bottom algae, some of the planktonic organisms that are found in their stomachs are probably those which have settled on the bottom or were washed shorewards from open waters but they do feed directly on plankton (Ref. 2). A maternal mouthbrooder, males make complex courtship structures in the substrate (Ref. 118638). Was a major component of the fisheries catch in Lake Victoria (Ref. 118638). Some pond culture attempted (Ref. 118638). IUCN conservation status is critically endangered (Ref. 118638).

生存在溫度範圍從 23.0-28.0 °C 。 (參考文獻 3) 偶然地形成魚群。 主要日行性。 成魚吃主要在底部藻類上,一些浮游性生物那是發現於他們的腹部是可能那些那裡有在底部上安頓或者被沖刷向岸的從開放的水域但是它們直接地以浮游生物為食.(參考文獻 2)

Life cycle and mating behavior Maturities | 繁殖 | Spawnings | Egg(s) | Fecundities | 仔魚

Nests are built on sandy bottoms in shallow waters. Each nest consists of a central shallow saucer 13-15 cm in diameter, around which is a circle of small pits. This structure is the center of a larger pit, 30-39 cm in diameter. Breeding pair makes the T-stand. Female lays batches of eggs; picks them up and sucks at the male's genital tassel. 非洲: 維多利亞湖與它的支流; 在 Murchison 秋天上面的維多利亞尼羅河; 湖 Kyoga 湖, Kwania 與索爾斯堡。

主要參考資料 Upload your references | 參考文獻 | 合作者 : Kullander, Sven O. | 合作者

Trewavas, E., 1983. Tilapiine fishes of the genera Sarotherodon, Oreochromis and Danakilia. British Mus. Nat. Hist., London, UK. 583 p. (Ref. 2)

IUCN 瀕危狀態 (Ref. 130435)

  近危 (NT) (A2bcde); Date assessed: 07 February 2020

CITES

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

對人類具威脅

  無害處的





人類使用

漁業: 商業性; 養殖: 實驗的; 水族館: 商業性
FAO - Publication: search | FishSource |

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參考文獻

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Estimates based on models

Phylogenetic diversity index (Ref. 82804):  PD50 = 0.5000   [Uniqueness, from 0.5 = low to 2.0 = high].
Bayesian length-weight: a=0.01585 (0.00707 - 0.03555), b=2.97 (2.79 - 3.15), in cm total length, based on LWR estimates for this Genus-body shape (Ref. 93245).
營養階層 (Ref. 69278):  2.0   ±0.00 se; based on food items.
Generation time: 3.1 ( na - na) years. Estimated as median ln(3)/K based on 2 growth studies.
回復力 (Ref. 120179):  中等的, 族群倍增時間最少 1.4 - 4.4年 (Fec=500).
Fishing Vulnerability (Ref. 59153):  Low vulnerability (18 of 100).
價格種類 (Ref. 80766):   Unknown.