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A new look at the Lake Superior biomass size-spectrum
Citation:
Yurista, P., D. Yule, M. Balge, J. VanAlstine, J. Thompson, A. Gamble, T. Hrabik, J. Kelly, J. Stockwell, AND M. Vinson. A new look at the Lake Superior biomass size-spectrum. Presented at American Fisheries Society, Quebec City, CANADA, August 17 - 21, 2014.
Impact/Purpose:
not applicable
Description:
We combined data from multiple sampling programs to describe the Lake Superior pelagic biomass size structure. The data represented phytoplankton, zooplankton and prey-fish that spanned over 10 orders of magnitude in size and two time periods separated by five years. The biomass size-spectrum was stable over the 5-year time frame. The primary scaling or overall slope of the normalized biomass size-spectra (NBSS) for the combined years was -1.113. The slope was consistent with a previous estimate for Lake Superior (-1.10) that was based on phytoplankton and zooplankton (Sprules and Munawar 1986). Periodic dome structures within the overall biomass size-spectrum were fit to polynomial regressions. The regressions described observed sub-domes that occurred within the classical taxonomic positions (algae, zooplankton, and fish). This more restricted interpretation of periodic dome structure was aligned more closely with predator-prey size relationships that existed within the zooplankton (herbivorous, predacious) and fish (planktivorous, piscivorous) taxonomic positions. Domes were spaced approximately every 3.78 Log10 units along the axis and with a decreasing peak magnitude of -4.1 Log10 units. The relative position of the algal and herbivorous zooplankton domes predicted well the subsequent biomass domes for larger predatory zooplankton and planktivorous prey fish.