ABSTRACT

Arthropod community structure in Jaja Creek and adjoining downstream section of Imo River was determined for a period of two years from January 2020 to December 2021. Aquatic arthropods are important components of an aquatic ecosystem and studying its community structure is pertinent. Three sampling sites each were marked out along the stretch of the Jaja creek and adjoining Imo River, plus Control sampling site at the conference point of the Creek and the River. Collection of samples; water, sediment, and arthropods, were carried out in the seven (7) sampling sites every month. The collected water and sediment samples were fixed with 1:1 Nitric acid. Physico-chemical parameters; temperature, pH, DO, and electrical conductivity, were measured in situ, while the remaining physico-chemcial parameters, nutrients, and heavy metals were measured from the water and sediment samples in the laboratory using standard methods. Collections of arthropod fauna were done across the seven sampling sites. The collected arthropod samples were stored properly and transported to the laboratory where some ofthe arthropod fauna for bioaccumulation analysis were randomly selected and stored in a refrigerator, while the remaining were preserved with 70% ethyl alcohol until identification and counting. The results revealed that the temperature ofwater for the two water bodies ranged from 26.20°C to 29.00°C with an overall mean concentration of 26.96±0.07°C, and was within the recommended limit for water and sediment, while pH ranged from 6.01 to 7.09 with an overall mean concentration of 6.41±0.02, TSS ranged from 62.07 to 70.18mg/l with an overall mean concentration of 66.04±0.16mg/l, electrical conductivity range was from 118.98ps/cm to 221.14ps/cm, and DO range was from 4.10 to 4.92 mg/1 with an overall mean concentration of 4.52±0.03mg/l. Fifty (50) different arthropod species were identified and grouped into three classes of Crustaceans, Insecta, and Arachnida, with nine orders, and 23 families. Among the arthropod species identified in this study were Sesarma sp, Sesarma, Armases sp, Neosarmatium, Nematopalaemon sp, Macrobrachium, Penaeus sp, Callinectes amnicola, C. pellidus, Carcinus sp, and Chironomus sp. Members of the class Insecta and families of sesarmidae, pilumnidae, and Penaeidae were collected and identified for the first time in this section of the Niger Delta Creek and Imo River. A total of 143,354 individual arthropod species were collected. The class Crustaceans accounted for the most numerical abundance of 135,809 and a relative abundance of 94.74%, followed by the class Insecta with total numerical abundance of 7,339 (5.12%). The variance results revealed that there was a significant difference between the arthropod species community by sampling sites. As a result of seasonal condition of the study area, temperature, pH, nitrate, sulphate, Chromium, Zinc, Salinity and sediment composition were the principal environmental factors affecting the arthropod species community structure. Nevertheless, a strong conservation plan should be established for the preservation of the water bodies' qualities and in turn, reserving the well-being of the aquatic arthropod fauna given their great economic value in the catchment area and the nation at large.