Production ecology of <i>Hexagenia limbata</i> in Savanne Lake, Ontario

Abstract

The population dynamics of the burrowing mayfly Hexagenia limbata was examined in Savanne Lake, a small, shallow, dark-water lake in northwestern Ontario. Hexagenia limbata in Savanne Lake has a 2-year life cycle with a larger cohort emerging on alternate years. The mean biomass [Formula: see text] varied from 0.36 g/m 2 (wet weight) to 2.98 g/m 2 , while mean numbers varied from 34/m 2 to 121/m 2 . Annual production (P) was calculated from samples collected monthly during the period of growth for 1979 and 1980. The Allen curve, instantaneous growth, and size frequency methods estimated annual production as 4.80, 4.78, and 5.59 g/m 2 (wet weight), respectively. The corresponding annual P/B ratios calculated by the three methods were 2.1, 2.1, and 2.6.