A suction pump sampler for invertebrate drift detects exceptionally high concentrations of small invertebrates that drift nets miss

Hydrobiologia
By: , and 

Links

Abstract

Invertebrate drift is a key process in riverine ecosystems controlling aquatic invertebrate movement, distribution, and availability to fish as prey. However, accurately sampling drift across a wide range of invertebrate sizes is difficult because small invertebrates slip through coarse-mesh drift nets, and fine mesh clogs more easily, which reduces filtration efficiency and measurement accuracy. To avoid this limiting tradeoff, we developed a gas-powered drift pump which pours 20 m3/hour of river water through nested 80- and 750-m nets suspended in the air, and we tested it against a conventional 250-m drift net during low and high flows in a clearwater Alaskan river. The drift pump detected a geometric mean drift concentration of 467 invertebrates m-3 and maximum of 5637 m-3, eleven times the mean concentration of 42 m-3 from the drift net. Invertebrates  3 mm length, primarily chironomids, comprised the entire difference. Studies in which the drift of 0.5 – 3 mm invertebrates might be relevant, such as foraging models investigating the growth of juvenile drift-feeding fishes, should consider using similar methods to quantify small invertebrate drift, lest they underestimate it by an order of magnitude.
Publication type Article
Publication Subtype Journal Article
Title A suction pump sampler for invertebrate drift detects exceptionally high concentrations of small invertebrates that drift nets miss
Series title Hydrobiologia
DOI 10.1007/s10750-022-04849-1
Volume 849
Year Published 2022
Language English
Publisher Springer
Contributing office(s) Coop Res Unit Seattle
Description 13 p.
First page 2077
Last page 2089
Country United States
State Alaska
Other Geospatial Chena River
Google Analytic Metrics Metrics page
Additional publication details