MORPHOLOGICAL DESCRIPTION AND ABUNDANCE ESTIMATION OF SUDANONAUTES AFRICANUS IN THE AQUATIC ECOSYSTEMS OF MAKURDI, NIGERIA

Abstract

Freshwater crabs are a vital macro-invertebrate group in tropical inland waters worldwide, serving as indicators of good water quality and playing a significant role in nutrient cycling in tropical freshwater ecosystems. The West African freshwater crab, belonging to the family Potamonautidae, consists of over 88 species that are found in various streams and river systems across Africa. These crabs have adopted freshwater, semi-terrestrial, or terrestrial modes of life, and studying the population structure and biology of freshwater crabs is crucial for understanding their ecological and economic importance. Morphometric analysis is a powerful tool for population studies and provides valuable information on size relationships, distinguishing characters, and growth patterns, which are essential for further studies on species life history and resource management. Despite their ecological and economic importance, there is a dearth of information on the population structure and biology of freshwater crabs, including the Sudanonautes africanus, in the Lower River Benue, Makurdi, Benue State, Nigeria. Therefore, this study aimed to determine the abundance and some aspects of the biology of S. africanus, such as length-weight relationship and condition factors, along the Lower River Benue, Makurdi, Benue State. The length-weight relationship in aquatic animals has wide application in delineating growth patterns during their developmental pathways. Information about individual body weight-length/width relationships in populations is important for estimating the population size of a stock. The length-width/weight relationships are more suitable for evaluating crustacean populations. This study utilized an innovative method by calculating the length of crabs from their weight by using lengthweight regression, which is extensively used to estimate length from weight in crustacean studies. This study presents information that is critical in describing the biology and population structure of S. africanus in the Lower River Benue, Makurdi, Benue State, Nigeria.