Design and use of a benthic sled for quantitative sampling of epibenthic macroinvertebrates in lakes

Benthic macroinvertebrates, including epibenthic taxa, affect the structure and function of lake ecosystems. This article describes the design and application of a benthic sled for quantitative sampling of epibenthic macroinvertebrates. Evaluation and testing of the sled included measurements of filtration efficiency and capture efficiency, as well as comparisons of sled samples with samples from a D-frame net and a coring sampler. Filtration efficiency for the benthic sled was 33 ± 2.8% (mean ± SE) and was not influenced by tow distance over distances up to 15 m. After correction for filtration efficiency, capture efficiency as determined by underwater videography was 83 ± 9.4% (mean ± SE). We found no differences between devices for sampling Corixidae, but Siphlonuridae were sampled much more effectively by the benthic sled than with the D-frame net. Thus, there may be taxonomic biases with standard sweeps using a D-net. For a set of samples from 13 mountain lakes in Colorado, community composition differed greatly between samples collected with the benthic sled and those collected with a coring sampler. The benthic sled described here is a useful tool for the study of epibenthic macroinvertebrates in lakes generally, and particularly in fishless lakes and other lakes where epibenthic taxa can be dominant. Ultimately, application of benthic sleds in studies of lake benthos, in combination with other sampling devices such as piston corers, may contribute to a more complete understanding of benthic communities, population dynamics, and energy flow in lake ecosystems.