Ichthyoplankton nets are equipped with a cod end box. Fishes are captured in the cod end and are transported to the laboratory for identification and determination of larval development phase.

Nets are equipped with flow meters to determine the volume of water filtered. Therefore, parameters such as species density,catch-per-unit effort, and relative abundance can be based on filtered water volume.

Similarly, fine mesh nets are also used for capturing zooplankton. These microscopic organisms are preserved and transported back to the laboratory for identification. Zooplankton evaluations are used as an index of primary production in aquatic systems, and are the basis of the aquatic food chain. Larval and filter feeding fishes rely primarily on zooplankton as a food.