Asian Journal of Fisheries and Aquatic Research

Shellfish are those aquatic animals with exoskeleton covering as chitin. Crabs are crustaceans of the family of decapoda, sexually dimorphic and omnivores. Over the years identification of organisms has been based on morphological characteristics and that has proven difficult because of alterations from environment and inters- special alterations. This research was aimed at elucidating the DNA barcodes of the shellfish obtained from Akor and Itu Rivers from Abia State and Akwa Ibom state Nigeria respectively. The methods of identification included DNA extraction, Agarose Gel Electrophoresis, Polymerase Chain Reaction, Sequencing and Phylogenetic analysis. Crab samples were collected for the period of 18 months running from May 2023 through October 2024 covering different seasons of Nigeria from the different sites. The crabs caught where average number of 14.97±11.93 and average weight of 33.73±11.258g. the crabs obtained from Akor River were 6.42±2.37 and the ones obtained from Itu River was 23.53±11.52. there were low number of catch from the rivers generally during the rainy season such as 8.75±2.99, 8.75±1.26 and 9.50±1.91 of the moth of June, July and August 2023. Although there were more number of crabs caught from Itu river, the weight of crabs obtained from Akor river with 35.64±11.67g were bigger than Itu river with 31.81±10.71g.

Females caught from the rivers were 15.22±12.48 and the males 14.72±11.54. The PCR showed availability of the DNA samples available in the content as they moved in the electrolyte medium at less than 600bp. The crabs after sequencing showed 95% similarity with Sudanonates floweri after blasting and more than 90% pair-wise sequence alignment. The phylogentic tree further expressed their close relationships with other species along the lines of identification and genera.