To print a PDF copy of this page, click here. Procedures will be altered to fit the needs of the client for specific projects. Samples are unpacked upon receipt and preservative levels checked. Non-smear labels are made that go on the inside of sample jars. The entire sample is floated in water in a white plastic tray.
Large debris is rinsed and removed.
The sample is then elutriated until all organic matter and invertebrates are floated off the mineral residue. The mineral residue remaining in the white pan after elutriation is searched for stone-cased caddisflies and molluscs that have not floated off. Unless otherwise specified by the client, a portion of the sample will be sorted that contains 500-600 organisms. The Caton Tray is normally used to randomly obtain a fraction of the total sample containing 500-600 organisms. Sample data is converted to a full sample basis.