Abstract
A classification system for dividing planktivorous predators into functional groups is proposed. The system is based on the tactics by which predators encounter and subdue prey. Vertebrate predators are classified as either nonvisual filter feeders or visual particulate feeders; invertebrate predators are classified as cruising raptorial feeders, ambush raptorial feeders, cruising entangling feeders, or ambush entangling feeders. Some observed and predicted trends in the patterns of prey selection associated with the various functional groups are described.