The genetic characterization of Clarias gariepinus was conducted in this study. Thirty (30) C. gariepinus specimens were collected, fifteen (15) each from the wild and farms in northeastern Nigeria for their genetic relatedness and diversity using the RAPD markers. DNA extraction from the blood sample was performed using the Gene Jet Genomic DNA Purification Kit. Five primers were used in employing PCR and amplified 402 RAPD bands from the four strains of Clarias gariepinus. Three hundred and six (76.12%) bands were polymorphic while 86 (21.39%) were monomorphic. The percentage of polymorphism obtained from farmed and wild populations ranged from 58 (47.3%) to 69 (75.9%), respectively. The polymorphic bands per loci within the populations ranged from 67.9% to 82.0%. The mean numbers of inbreeding coefficient (FIS) were 0.083 and 0.053 in the farmed and wild populations. Gene diversity values within farmed and wild populations (Ht) were 0.4522 and 0.4018. The mean genetic differentiation (FST) ranged between (0.203) in the farmed and 0.129 in the wild populations. The analysis of molecular variance revealed that there was 96% of genetic variance within the population and 4% among the population. The genetic identity and distance of four populations were 0.9490 and 0.1038, respectively. The phylogenetic measure has shown that the four strains were divided into two clusters at approximately 0.089 similarity levels. The result indicated a significant level of genetic variation and minimal dendrogram separation in Clarias gariepinus in northeastern Nigeria. Conclusively, this information will be a useful tool for the genetic and breeding program of Clarias gariepinus.

The anesthetic effects of clove (Eugenia aromaticum) seed extract on Clarias gariepinus fingerlings were investigated under semi-arid conditions. Various concentrations of the clove seed extract at 25.0, 50.0, 75.0, 100.0, 125.0 and 150.0mg per liter of water were used for the experiment. Each concentration was tested on a group of 10 Clarias gariepinus fingerlings (24.13 25.30g in weight and 5.97 7.00 cm in length) in glass aquariums. There was a decrease in induction time as the concentration of the clove seed extract increased. Fingerlings treated with 150mg/l of the extract produced the shortest induction time (2.28±0.15 minutes), followed by fish treated with 100 and 125mg/l (3.31±0.55 and 3.07±0.07 minutes, respectively). The longest induction time (10.60±0.98, 7.52±0.25 and 5.96±1.17 minutes) was observed in fingerlings sedated with 50, 25 and 75mg/l, respectively. Recovery was significantly faster (2-3.92 minutes) in fish treated with lower dosages (25 to 125mg/l) of the clove seed extract. Mortality rates after 24 hours of recovery were higher (4.79±0.25 and 3.10±0.54%) in fish anesthetized with higher (150 and 125mg/l) concentrations of the clove seed extract, respectively.