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The diversity and abundance of fish species in Ekpene Ukpa River were studied from July - October, 2020. Sampling was by direct observation of the fish species at the sampling sites following landing by fishermen. Frequency, counts, and percentages were employed to determine fish species composition and abundance, while a Microsoft Excel 2003 based program was used to determine the ecological indices. A total of 14 species belonging to seven (7) families were recorded. The family, Clarotidae had the highest relative abundance (38.1%) with the least value (2.38%) observed in the family Alestidae. The index of preponderance ranged from 0.0004 in Pellonula leonensis and Trachinotus teraria to 0.100 in Chrysichthys nigrodigitatus. The most abundant grouping of fish species was Chrysichthys igrodigitatus with 25.0% and the least in abundance were Pellonula leonensis and Trachinotus teraia with 1.19% each. The index of preponderance (IP) value of 0.10 was recorded for Chrysichthys nigrodigitatus which marked this species very significant in the study site. The study revealed that species richness and diversity were high in the month of October. Inference from the results clearly indicated that fish species were much diversified in all sampling months, and this is of great significance to the biodiversity of the study area. However, an inclusive management approach is recommended, such as educational awareness, involving of the local contents, and comprehensive rational planning on the management and development of the study site.

Aims: This work aimed at providing pieces of information on the trend and levels of heavy metals in shrimp, surface water and sediment from Iko river estuary, Eastern Obolo, South-South Nigeria. Study Design: The study area was demarcated into three stations for sampling. The sampling stations were subjectively categorized. Place and Duration of Study: The study which was carried out in Iko river estuary, Eastern Obolo, South-South Nigeria lasted for 12 months. Methodology: Samples were collected once a month for 12 months in a consecutive manner and analyzed using standard methods. Results: When compared to water and shrimps, sediments contained the highest concentration of heavy metals during the study period. Contrarily, water had the highest concentration (1.50 Mg/L) of Cd, compared to 0.85 Mg/Kg in sediment and 0.27 Mg/Kg in shrimps. Levels of Lead (Pb) in the study samples followed a similar trend like that of Cd. Zinc also followed a contrary pattern with shrimps having the highest concentration (65.35 Mg/L). Of all the metals studied, iron (Fe) was found to be the most abundant heavy metal in Iko River Estuary. Although levels of Fe were generally high in all the samples studied, concentration in sediment (113.99 Mg/Kg) far outweighed the concentrations in shrimps (227.11 Mg/Kg) and in water (184.35 Mg/L). These levels of heavy metals determined in the water, sediment and shrimps showed variations during the wet and dry seasons. Conclusion: The values were higher than the recommended limits. It can therefore be concluded that Iko River Estuary was always laden with heavy metals notwithstanding the season of the year. Accumulation of these metals in shrimps also indicates that sea foods from this river may not be suitable for consumption.