Epibenthic invertebrates can be good indicators of beach conditions and certain species are important prey for juvenile salmon. They live at the interface of bottom sediments and the water and can be sampled using a modified bilge pump. Invertebrate communities may vary depending on sediment size, presence of eelgrass and algae, and stressors such as shoreline development. Analysis can focus on counts of key juvenile salmon prey items such as harpacticoid copepods and amphipods, or processing of the entire assemblage to allow diversity measurements.
Two different kinds of pump can be used by modifying either a battery operated boat bilge pump or a hand operated bilge pump. Details on making them can be found here.