Burrowing mayflies in Lake Erie - a review

This paper describes the life history, distribution, and abundance of Hexagenia in Lake Erie, as shown by sediment core samples containing preserved Hexagenia remains dating back to about 1740, periodic sampling of living nymphal populations since about 1930, observations of emergences and mating swarms of adults, and the incidence of Hexagenia in fish stomachs. The roles of eutrophication and anoxia, and of oil and heavy metal pollution in the decline, near extinction, and delayed recovery of Hexagenia in the western basin are also discussed.