Production by Hexagenia limbata in a warm-water reservoir and its association with chlorophyll content of the water column

Abstract

We investigated the productivity of nymphs of the mayfly Hexagenia limbata in Lake Waco, a central Texas reservoir, and assessed its association with chlorophyll content of the water . We hypothesized that food availability measured as chlorophyll content of the water may directly associate with growth of Hexagenia and predict population productivity. To test this, we compared production by mayfly populations at two stations in the same reservoir ; a northern station receiving water input with high chlorophyll content, and a southern station receiving water with low chlorophyll content . Both stations had similar substrate type and abundant mayflies . Benthic samples were collected from October 1984 through September 1985, and dissolved oxygen and temperature of the water were monitored .Annual production (size-frequency method) was 1270 mg m -2 (P/B = 7 .5) at the northern station and 1990 mg M-2 (P/B = 6 .1) at the southern station . The mean standing crop was 323 mg m -2 at the southern station and 169mg m -2 at the northern station . Densities of mayflies at the two stations were not significantly different .Mean chlorophyll concentration (total mg pigment) during the sampling period was 23 .5 mg m -3 at the northern station and 16 .7 mg m -3 at the southern station . Therefore, the station with lower mean chlorophyll content had higher secondary productivity by Hexagenia . Conversely, the station with higher mean chlorophyll content had lower mayfly productivity . The productivity of the mayfly populations did not positively associate with the chlorophyll content of the water, and chlorophyll content did not predict the success of the population of Hexagenia . Variation in mayfly growth success was associated with differences in temperature and dissolved oxygen . The northern station with higher chlorophyll content and lower productivity had low dissolved oxygen and temperatures higher than optimum for growth .

Influence of salinity and temperature on the growth and production of a freshwater mayfly in the Lower Mobile River, Alabama

“…H. limbata required 2,588 degree ), and annual production to mean biomass ratios (P/ B) for Hexagenia limbata from eight locations across Eastern North America (modified from Giberson and Rosenberg 1994 4.1-4.6 3.8-3.9 6.1-7.5 3.5-5.4 2.7 2.1 ND ND Lobinske et al (1996) present study Welch and Vodopich (1989) Horst and Marzolf (1975) Hudson and Swanson (1972 Rikilik and Momot (1982) Heise et al (1987) Giberson andRosenberg (1994) days (dd) to develop to emergence based on laboratory rearing with temperature regimes from 6 to 26ЊC, and based on a minimum threshold of 10ЊC (McCafferty and Pereira 1984). In the Lower Mobile River, nymphs accumulated ϳ3,250 dd for emergence (based on daily temperatures from 23 September 1995 to 6 September 1996) in a thermal regime from ϳ5 to 32ЊC.…”

Boosted Beta Regression

“…Because Ephemeroptera are sensitive taxa, they may be disproportionately affected by higher chlorophyll- a levels. Additionally, high levels of Chlorophyll- a reduces mayfly secondary production [49], which would possibly further reduce their presence.…”

Habitat Selection by Two Species of Burrowing Mayfly Nymphs in the Les Cheneaux Islands Region of Northern Lake Huron

“…All feeding and growth and most natural population controls on Hexagenia limbata occur during the aquatic nymphal stage (Horst 1976). They are a valuable food source for secondary consumers during this stage in the life cycle, which can be as long as two years (Welch and Vodopich 1989). The H. limbata populations in northern Lake Huron have a two-year life cycle (Schloesser and Hiltunen 1984).…”