Densities of Hexagenia mayfly nymphs in western Lake Erie, 1999-2014

Densities of Hexagenia spp. mayfly nymphs by age class are presented from 1999 through 2014. This range is significant in that it includes the year of peak abundance following recovery from nearly 4 decades of near extirpation (~1960 through the mid-1990s) through a period of decline. This range overlaps with fluctuations in abundance of other potentially relevant species, such as Round Goby and Dreissena spp. mussels. A novelty of these data is the separation of age classes, which provides for potentially novel approaches to assessing mayfly trends.