Plankton Nets are a modification on the standard trawl used to collect planktonic organisms, of nearly any size, intact. Towed by a research vessel, Plankton Nets have a long funnel shape that allows them to catch differently sized plankton simply by changing the mesh size of the net. At the end of the funnel is a collection cylinder called a cod-end.
A ring net, a common form of Plankton Net, being readied for use during Arctic shelf research. (C.A. Linder, Wood's Hole Oceanographic Institute)
Bongo nets, such as these pictured here on the NOAA ship McARTHUR, are another common design. (NOAA Ocean Explorer)
The multinet, a vertically profiling Plankton Net used to collect depth-stratified samples of small zooplankton such as copepods. (Mid-Atlantic Ridge Ecosystems - MAR-ECO. Filipe Porteiro)
This amphipod trap is specially designed to collect intact specimens of zooplankton and small crustaceans such as amphipods. (Census of the Diversity of Abyssal Marine Life - CeDAMar)