Colour pattern of flanks, throat and chest as complementary criterion for identification of Tilapia zillii-T. guineensis-hybrids complex in Ayame man made lake, at Sub-Eastern of Cote d’ivoire


Céline Sidonie Koco Nobah, Yao Laurent Alla, Kouamé Affourmou

Pure strain Tilapia zillii and T. guineensis have been reproduced in order to obtain pure lines of these two species. The intraspecific crosses were then carried out, to engender first generation reciprocal hybrids F1A (T. zillii (Male) x T. guineensis (female)) and F1B (T. zillii (female) x T. guineensis (male)). The latters, have been reproduced each other to get F2A (F1A x F1A) and F2B (F1B x F1B) second generation hybrids. The flanks, throat and chest have been observed during the fish growth from the juvenile to adult stage. Reddish or pale reddish colorations were seen on flanks, and blackish or grayish flecks on the throat and the chest. Whatever the species and hybrids, small size samples (2 to 8 cm LS) considered as mixed show little or no shade on the parts of the body studied. Among T. Zilli, the males have pale red flanks while the throat and the chest are grayish. The females of this group show respectively reddish and blackish flecks. Whatever the sex, the T. guineensis flanks is reddish and the throat and the chest are blackish. Blade colors are observed in males of first generation hybrids and dark in the females group. Concerning the second generation hybrids, within a same sex group, hues are heterogeneous. Dark or light shades can be observed.


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