19. Oreochromis niloticus (Linnaeus, 1758), Exotic

Fig. 46

Etymology: Oreochromis: Latin, aurum = gold + Greek, chromis = a fish, perhaps a perch; niloticus: refers to the Nile River.

Common name: Nile Tilapia.

Taxonomy: Perca nilotica was described by Linnaeus [C.] 1758:290 [Systema Naturae, Ed. X v. 1] from Nile River. Holotype:? NRM LP 10.

Synonyms: Chromis triacantha Bowdich [S. L.] 1825:235, fig. 52 [Fishes of Madeira; ref. 590] Gambia River. Tilapia calciati Gianferrari [L.] 1924:242, fig. [Atti della Società Italiana di Scienze Naturali di Milano v. 63. Tilapia regani, Poll [M.] 1932:32, Pls. 1 (fig. 2), 2 (fig. 2) [Revue de Zoologie et de Botanique Africaines v. 23 (no. 1). Tilapia vulcani Trewavas [E.] 1933:315, fig. 1 [The Journal of the Linnaean Society of London. Zoology v. 38 (no. 259). Tilapia inducta Trewavas [E.] 1933:317, fig. 2 [The Journal of the Linnaean Society of London. Zoology v. 38 (no. 259).

Short description: Dorsal-fin spines 15–18, dorsal-fin soft rays 11–13, anal-fin rays III, 9–11, vertebrae 30–32. Oreochromis niloticus differs from O. mossambicus another introduced fish to the Arabian Peninsula by having 3–40 dark grey to black regularly shaped and set bars on caudal fin (increasing with fish size), all flank scales with dark-grey scale pockets, tip of membrane between dorsal-fin spine black, nuptial male whitish with pink anterior body and caudal fin.

General distribution: North and East Africa. Widely introduced elsewhere, including Mississippi and Florida (U.S.A.), Mexico, Honduras, Costa Rica, Brazil, Ecuador, Uruguay, Argentina, Madagascar, Malaysia, Indonesia, Philippines and southern Japan. Habitat: freshwater, brackish.

Distribution in Oman: It is widely distributed and established in Wadis and Aflaj (Fig. 47).

Examined material: ZM-CBSU: O003. On 101, 12, Oman: Dhofar Governorate: Wadi Darbat, 17°05’55”N, 54°27’04”E, H. R. Esmaeili, S.M. Al-Jufaili, A. H Masoumi, 02 Jan. 2022. ZM-CBSU: O005- On 113, 17, Oman: Ain Razat, 17°07’46”N, 54°14’19”E, H. R Esmaeili, S.M. Al-Jufaili, A.H. Masoumi, Jan. 2022.