Abstract |
Sampling devices used by aquatic biologists to collect macroinvertebrates in a lake or stream vary with the kind of substrate to be sampled. Even when properly used, these sampling devices collect large amounts of debris which may prevent the biologist from efficiently concentrating or separating macroinvertebrates in the sample. A combined washing-screening process, conducted immediately following collection, is the best procedure for concentrating and separating organisms from the sample. This procedure is usually accomplished with a No. 30 U. S. Standard Sieve (openings of approximately 0.6 millimeter) that retains macroinvertebrates. The design and utilization of this device is described. |