Status of pelagic prey fishes in Lake Michigan, 2013

Effect of lake-wide planktivory by the pelagic prey fish community in Lakes Michigan and Ontario

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f95-148 ◽

1995 ◽

Vol 52 (7) ◽

pp. 1546-1563 ◽

Cited By ~ 58

Author(s):

Peter S. Rand ◽

Donald J. Stewart ◽

Brian F. Lantry ◽

Lars G. Rudstam ◽

Ora E. Johannsson ◽

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Keyword(s):

Lake Michigan ◽

Supply And Demand ◽

Lake Ontario ◽

Production Model ◽

Trophic Relationships ◽

Prey Fish ◽

Prey Resources ◽

Wet Weight ◽

Pelagic Prey ◽

Zooplankton Production

We compared predatory demand by pelagic planktivorous prey fish with invertebrate production in Lake Michigan during 1987 and in Lake Ontario during 1990. Predation by the planktivores in Lake Ontario was nearly fourfold higher than in Lake Michigan (approx. 87 g wet weight∙m−2∙year−1). Predation rates on Mysis were comparable in Lakes Michigan and Ontario (approx. 21 g∙m−2∙year−1), while predation on Diporeia was markedly higher in Lake Michigan than in Lake Ontario (21.3 vs. 8.5 g wet weight∙m−2∙year−1). In Lake Ontario, predatory demand on zooplankton exceeded our best estimate of production by a factor of 1.7. Similarly, predation estimates on Mysis in Lake Ontario were 1.2–2.0 times the estimated rate of production, depending on the production model used. Lake Michigan planktivores consumed approximately 55% of available zooplankton production in 1987, indicating that competition for prey resources, if operating, was not as intense as that in Lake Ontario in 1990. It is unclear how to resolve the paradox that predation could markedly exceed available prey production in some cases. There could be sources of error in the estimates of both the supply and demand sides of these trophic relationships.

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Ultrastructure of Melosira resting cell rejuvenation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010011355x ◽

1984 ◽

Vol 42 ◽

pp. 734-735

Author(s):

C. E. M. Bourne ◽

L. Sicko-Goad

Keyword(s):

Electron Microscopy ◽

Lake Michigan ◽

Light And Electron Microscopy ◽

Resting Cells ◽

Planktonic Diatoms ◽

Resting Cell ◽

Vegetative Survival ◽

Cytological Changes ◽

Recent Attention ◽

Freshwater Diatom

Much recent attention has been focused on vegetative survival forms of planktonic diatoms and other algae. There are several reports of extended vegetative survival of the freshwater diatom Melosira in lake sediments. In contrast to those diatoms which form a morphologically distinct resistant spore, Melosira is known to produce physiological resting cells that are indistinguishable in outward morphology from actively growing cells.We used both light and electron microscopy to document and elucidate the sequence of cytological changes during the transition from resting cells to actively growing cells in a population of Melosira granulata from Douglas Lake, Michigan sediments collected in mid-July of 1983.

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