Population dynamics, life-history traits of and habitat use by two sympatric nothobranchiid fishes in a tropical stream, Kainji Lake Basin, Nigeria

Abstract

Population dynamics and life-history traits of two sympatric nothobranchiid killifishes, Epiplatys bifasciatus and E. spilargyreius, were studied for 24 months in an intermittent stream in the Kainji Lake Basin, Nigeria. Epiplatys bifasciatus was more abundant throughout the study period, but monthly abundance of both species followed the same pattern. For both species, growth parameters and life-history strategies are characterised by small size, high growth rate, early maturity, high reproductive effort through daily spawning, short generation time, short life span and high mortality rate. Both species reproduce throughout the year, with peak periods of recruitment during the February to April and October to November periods. The population structures showed a preponderance of females over males, while males attained a larger total length than females. Three habitat types (vegetated pool, vegetated riffle, and marsh) were preferred by both species, whilst unvegetated habitats were avoided. Epiplatys spilargyreius was fairly specific in its habitat preference, with a significant positive correlation (r = 0.65, p < 0.05) to marshy habitat, whereas E. bifasciatus showed some habitat-use plasticity.

African Journal of Aquatic Science 2009, 34(1): 45–56