Dynamics of Lake Michigan Plankton: A Model Evaluation of Nutrient Loading, Competition, and Predation

1988 ◽  
Vol 45 (1) ◽  
pp. 165-177 ◽  
Author(s):  
Donald Scavia ◽  
Gregory A. Lang ◽  
James F. Kitchell
Keyword(s):  
Species Interactions ◽  
Lake Michigan ◽  
Nutrient Loading ◽  
Substantial Contribution ◽  
Alosa Pseudoharengus ◽  
Calanoid Copepods ◽  
Nutrient Excretion ◽  
Blue Green Algae ◽  
Phytoplankton Species Composition ◽  
Alternative Hypotheses

Lake Michigan's offshore ecosystem has been altered dramatically during the past decade. Summer zooplankton dominance has changed from calanoid copepods to Daphnia and the substantial contribution of filamentous blue-green algae to summer phytoplankton has been replaced by phytoflagellates. These changes occurred concurrently with reduced P load, P concentration, and abundance of the dominant zooplanktivore, the alewife (Alosa pseudoharengus). In this analysis we pose alternative hypotheses of nutrient loading and species interactions as determinants of zooplankton and phytoplankton species composition in the summer epilimnion. We evaluate these hypotheses with a food web model that was calibrated to measurements of the 1980s Lake Michigan plankton composition and algal production, sedimentation, and growth rates and literature estimates of zooplankton secondary production and nutrient excretion. The model simulates the influence of gradients of both P load and alewife abundance on predation–competition interactions. We conclude that summer plankton composition in Lake Michigan is controlled largely by predation. The model further predicts a return to a plankton community similar to that of the 1970s under a scenario of increasing invertebrate predation by a new zooplankton species for Lake Michigan, Bythotrephes cederstroemi.

Influence of Salmonine Predation and Weather on Long-Term Water Quality Trends in Lake Michigan

1986 ◽  
Vol 43 (2) ◽  
pp. 435-443 ◽  
Author(s):  
Donald Scavia ◽  
Gary L. Fahnenstiel ◽  
Marlene S. Evans ◽  
David J. Jude ◽  
John T. Lehman
Keyword(s):  
Water Quality ◽  
Management Practices ◽  
Lake Michigan ◽  
Sediment Resuspension ◽  
Weather Conditions ◽  
Water Clarity ◽  
Alosa Pseudoharengus ◽  
Calanoid Copepods ◽  
Chl A ◽  
Secchi Disk Transparency

Trends in Lake Michigan water quality over 1975–84 appear to reflect reduced nutrient loadings as indicated by gradual declines in spring total phosphorus (TP) and summer epilimnetic chlorophyll a (Chl a). Deviations from these trends during 1977 and 1983–84 were apparently caused by abiotic and biotic factors, respectively. Prolonged ice cover during 1977 decreased sediment resuspension resulting in lower TP, reduced Chl a levels, and increased water clarity. A similar dramatic result occurred in 1983 and to a lesser extent in 1984, but via a different mechanism. Burgeoning populations of stocked salmonines reduced populations of the planktivorous alewife (Alosa pseudoharengus), which allowed large Daphnia to flourish. Because the Daphnia are more voracious and nonselective grazers than the formerly dominant calanoid copepods, they reduced seston concentrations, causing dramatic increases in Secchi disk transparency. These exceptions demonstrate the far-reaching consequences that unusual weather conditions and fish management practices may have on water quality indicators.

Feeding-Behavior Repertoire of the Alewife, Alosa pseudoharengus, and the Ciscoes Coregonus hoyi and C. artedii

1978 ◽  
Vol 35 (2) ◽  
pp. 249-253 ◽  
Author(s):  
John Janssen
Keyword(s):  
Great Lakes ◽  
Feeding Behavior ◽  
Key Words ◽  
Lake Michigan ◽  
Alosa Pseudoharengus ◽  
Calanoid Copepods ◽  
Mysis Relicta ◽  
Particulate Feeding ◽  
Coregonus Hoyi

Particulate feeding, where fish orient to and take prey one at a time, is shown by the alewife, Alosa pseudoharengus, and the ciscoes Coregonus hoyi and C. artedii. Specialized particulate feeding is found in ciscoes and alewives for capturing strongly swimming prey such as Mysis relicta and calanoid copepods. This involves simultaneous darting and sucking. Alewives filter feed by swimming with the mouth fully agape for 0.5–2 s while driving hard with the tail. Ciscoes do not filter feed, but they and alewives display gulping behavior where fish open and close the mouth 2–3 times/s, do not drive hard with the tail, and may take more than one prey per gulp. The alewife has difficulty feeding near or on the bottom. The ciscoes feed easily on or near the bottom and will also take buried prey. Key words: Alosa pseudoharengus, Coregonus hoyi, C. artedii, feeding behavior, Great Lakes, Lake Michigan

Early life history of alewife Alosa pseudoharengus in southwestern Lake Michigan

2015 ◽  
Vol 41 (2) ◽  
pp. 436-447 ◽  
Author(s):  
Michael J. Weber ◽  
Blake C. Ruebush ◽  
Sara M. Creque ◽  
Rebecca A. Redman ◽  
Sergiusz J. Czesny ◽  
...  
Keyword(s):  
Life History ◽  
Early Life ◽  
Lake Michigan ◽  
Early Life History ◽  
Alosa Pseudoharengus ◽  
History Of

An Energetics Model for Lake Trout, Salvelinus namaycush: Application to the Lake Michigan Population

1983 ◽  
Vol 40 (6) ◽  
pp. 681-698 ◽  
Author(s):  
Donald J. Stewart ◽  
David Weininger ◽  
Donald V. Rottiers ◽  
Thomas A. Edsall
Keyword(s):  
Lake Michigan ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
High Energy ◽  
Alosa Pseudoharengus ◽  
Fishing Mortality ◽  
Age Classes ◽  
Short Term ◽  
Conversion Efficiencies

An energetics model is implemented for lake trout, Salvelinus namaycush, and applied to the Lake Michigan population. It includes an egestion function allowing any proportional mix of fish and invertebrates in the diet, a growth model accounting for both ontogenetic and seasonal changes in energy-density of predator and prey, a model for typical in situ swimming speed, and reproductive energy losses due to gametes shed. Gross conversion efficiency of energy by lake trout over their life (21.8%) is about twice the efficiency of converting biomass to growth because they store large amounts of high-energy fats. Highest conversion efficiencies are obtained by relatively fast-growing individuals, and over half the annual energy assimilated by older age-classes may be shed as gametes. Sensitivity analysis indicates a general robustness of the model, especially for estimating consumption by fitting a known growth curve. Largest sensitivities were for the intercept and weight dependence coefficients of metabolism. Population biomass and associated predatory impact of a given cohort increase steadily for about 3.5 yr then decline steadily after fishing mortality becomes important in the fourth year in the lake. This slow response time precludes manipulation of lake trout stocking densities as a means to control short-term prey fluctuations. Predation by lake trout on alewife, Alosa pseudoharengus, has been increasing steadily since 1965 to about 8 400 t∙yr−1, and is projected to rise to almost 12 000 t∙yr−1 by 1990.

Nutrient loading by anadromous alewife (Alosa pseudoharengus): contemporary patterns and predictions for restoration efforts

2010 ◽  
Vol 67 (8) ◽  
pp. 1211-1220 ◽  
Author(s):  
Derek C. West ◽  
Annika W. Walters ◽  
Stephen Gephard ◽  
David M. Post
Keyword(s):  
Nutrient Loading ◽  
Mesocosm Experiment ◽  
Alosa Pseudoharengus ◽  
Nutrient Budgets ◽  
Freshwater Lakes ◽  
Phosphorus Load ◽  
Coastal Lakes ◽  
Density Dependent ◽  
Early Survival ◽  
The 1960S

Anadromous alewives ( Alosa pseudoharengus ) have the potential to alter the nutrient budgets of coastal lakes as they migrate into freshwater as adults and to sea as juveniles. Alewife runs are generally a source of nutrients to the freshwater lakes in which they spawn, but juveniles may export more nutrients than adults import in newly restored populations. A healthy run of alewives in Connecticut imports substantial quantities of phosphorus; mortality of alewives contributes 0.68 g P·fish–1, while surviving fish add 0.18 g P, 67% of which is excretion. Currently, alewives contribute 23% of the annual phosphorus load to Bride Lake, but this input was much greater historically, with larger runs of bigger fish contributing 2.5 times more phosphorus in the 1960s. A mesocosm experiment in a nearby lake showed that juvenile alewife growth is strongly density dependent, but early survival may be too low for juvenile outmigration to balance adult inputs. In eutrophic systems where nutrients are a concern, managers can limit nutrient loading by capping adult returns at a level where juvenile populations would not be suppressed.

Changes in the Apparent Temperature Optima of the Plankton of Lake Michigan at Chicago, Illinois

1979 ◽  
Vol 36 (10) ◽  
pp. 1169-1173 ◽  
Author(s):  
J. C. Makarewicz ◽  
R. I. Baybutt ◽  
K. Damann
Keyword(s):  
Lake Michigan ◽  
Cold Water ◽  
Plankton Community ◽  
Apparent Temperature ◽  
Optimum Temperature ◽  
Seasonal Periodicity ◽  
Blue Green Algae ◽  
Plankton Distribution ◽  
Temperature Optima ◽  
Water Species

Forty years (1937–76) of data from Lake Michigan water intakes at Chicago, Illinois, were examined to explain reported differences in the apparent temperature optima of phytoplankton. The bimodal seasonal plankton distribution, typical at Chicago, still occurs. However, there has been a shift in seasonal periodicity with spring peaks occurring in March from 1957 to 1976 instead of May–June as previously reported for 1937–56. An optimum temperature of 10 °C for the plankton community was observed between 1936 and 1956, while for the last 20 yr an optimum temperature range from 0 to 4 °C was observed. This change in optimum temperature of the plankton community is related to a change in the abundance of the genera Asterionella, Fragilaria, Stephanodiscus, and Tabellaria. Asterionella and Fragilaria were the dominant spring plankton with maximum standing crops observed around 10 °C prior to 1956. Stephanodiscus first increased significantly in 1957 and was the dominant spring plankter through 1976. More recently (1972–76), blue-green algae have increased in numbers. Differences in apparent temperature optima reported are real and are caused by the emergence of cold water species of Stephanodiscus as the dominant spring plankter from 1957 to 1976. Key words: plankton, temperature optima, Lake Michigan

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