The importance of size-frequency relationships for predicting ecological impact of zebra mussel populations

Department

Natural Sciences

Document Type

Article

Publication Source

Hydrobiologia

Publication Date

1996-01-01

Volume

332

Issue

3

First Page

151

Last Page

158

Abstract

Although most physiological processes of bivalves are highly size- dependent in a non-linear manner, often only total densities of populations of freshwater bivalves such as the zebra mussel are reported rather than size-frequency information. This can cause serious errors when trying to predict or assess the environmental impacts of these filter feeders on planktonic communities or the role of their pseudofeces in transferring materials from the plankton to the benthos. We used a bioenergetics model to examine the effect that differing size-frequency distribution has on influencing total phytoplankton consumption and pseudofeces production. We constructed different size-frequency distributions of 1000 zebra mussels with the same mean length or same mean body mass for comparison. In addition, we used several size-frequency distributions from the published literature. The size frequency distribution of a population had a tremendous impact on both total consumption and pseudofeces production with rates varying by more than an order of magnitude (43.5 g consumption by 1000 smaller mussels to 654 g for a population dominated by large mussels). These data emphasize the importance of knowing not only population density but population size structure in order to accurately understand and predict the impacts of zebra mussels, or any filter feeder on pelagic and benthic communities. This work also demonstrates the usefulness of a tool such as our bioenergetics model for partitioning the relative impacts of densities and size on a variety of factors such as consumption and pseudofeces production.

Keywords

introduced species, size-frequency distribution, zebra mussel

DOI

10.1007/BF00031920

https://doi.org/10.1007/BF00031920

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