Spatio-temporal variability of small fishes related with environmental factors in a typical domestic tap water lake, Eastern China

The knowledge of prey small fish stock, distribution and abundance is necessary to guide stocking of piscivorous fish for the biomanipulation in domestic tap water lakes. This study describes the current status of small fish community in Kuilei Lake (China), and examines the spatial and seasonal variations of the community in relation to key environmental factors. Based on submerged macrophyte cover and water depth, the lake was divided into five major habitats: (1) macrophyte covered shallow habitat of water depth < 2.00 m, (2) uncovered or less-covered shallow habitat (2.00 m-3.50 m), (3) uncovered medium shallow habitat (3.50 m-5.00 m), (4) uncovered medium deep habitat (5.00 m-6.50 m) and (5) uncovered deep habitat (6.50 m-8.50 m). The abundance and composition of small fish were monitored by benthic fykenet sampling from April 2013 to January 2014. A total of 2881 individuals belonging to 5 families and 21 species were collected. Based on their abundance (accounted for 88.96% of the total) and occurrence (more than 33.33%), Acheilognathus chankaensis, Acheilognathus macropterus, Microphysogobio mictvstomus, Pseudorasbora parva and Rhinogobius giurinus were recognized as dominant small fish species. The results of correlation analysis identified that species richness (Sr), Shannon-Wiener diversity index (H') and Margalefs richness index (D) were significantly negatively correlated with water depth, but positively correlated with biomass of submerged macrophytes.Redundancy analysis (RDA) revealed that the spatial distributions of most small fishes were negatively associated with water depth. The details of these findings are beneficial to understanding the adaptation of the small fishes in degraded environments, and to developing suitable biomanipulation strategies for the management of fish resources and water quality in the lakes along the lower reach of the Changjiang (Yangtze) River basin