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A Suction Sampler for Quantitatively Sampling Benthos on Rocky Substrates in Rivers

1975; Wiley; Volume: 104; Issue: 2 Linguagem: Inglês

10.1577/1548-8659(1975)104 2.0.co;2

1548-8659

William F. Gale, J. Douglas Thompson,

Freshwater macroinvertebrate diversity and ecology

The dome (suction) sampler is a self-contained unit that consists of five main parts: (i) a transparent acrylic hemisphere to enclose an area of the river bottom; (ii) a bilge pump to vacuum organisms out of the sampler; (iii) a net to collect organisms as they are pumped out; (iv) a bag for collecting large stones; and (v) a band to seal the space between the dome and the substrate. The dome sampler was designed to be used by a SCUBA diver to sample benthos quantitatively on 0.18 m2 of cobble-gravel substrate in the North Branch of the Susquehanna River. The sampler was used throughout the year, often under such adverse conditions as strong currents, cold water, and poor visibility. The sampler can be used in water 0.4-1.0 m deep without SCUBA. Eighty-two percent of the organisms released inside the sampler were recovered during efficiency tests. Most organisms collected with the sampler were in identifiable condition. Ten minutes pumping per sample was required for best results. The sampler was more efficient than the Petersen, Ekman, and Ponar grabs, a corer, and the Surber sampler in collecting benthic macroinvertebrates from substrates in our study. Twenty-two families of benthic invertebrates were collected in dome and artificial substrate (Bar-B-Q basket) samples. Only 12 families occurred in both and there were major differences in the relative abundance of some of them. Population trends formulated with data from the two samplers did not agree.