Morphometric Measurements, Meristic Counts, and Molecular Identification of Alestes Dentex, Alestes Baremoze, Brycinus Nurse, and Brycinus macrolepidotus from the River Nile at Kreima

Twenty-two morphometric characters and seven meristic counts were recorded from 324 Alestes specimens from Kreima at the River Nile.

Specimens collected were identified to the species level as Alestes baremoze (100 specimens), Brycinus nurse (100 specimens), Brycinus macrolepidotus (24 specimens), and Alestes dentex (100 specimens). The principal component analysis showed that the lateral line scales and the scale above the lateral line contributed to the percentage variance by 97.01% and 2.56%, respectively. Discriminant function analysis was done to discriminate between field-collected samples of Alestes sp. The LLS, AFR, and LDFL (Longest of Dorsal Fin Lings) were found to be the main characters that discriminate between the four populations.

The first function showed that they were significantly different. This discrimination was a complete one since 98.1% of original grouped specimens and 97.8% of the cross-validated ones were correctly classified. The scatter plot of Discriminant scores from the three functions showed some relatedness between Alestes baremoze and Alestes dentex.

16S ribosomal RNA primers have been used to identify the species at the molecular level. All species have shown a characteristic band (680 bp) indicating successful amplification. Five RAPD primers have been used to investigate the Alestes species. Similar and dissimilar DNA bands indicate the evolutionary connections and genetic spacing, respectively. The derived dendrograms based on morphometric measurements and meristic counts were closer to that derived from the RAPD PCR results.

The study showed co-existence of four Alestes species in the main River Nile.