Particle image velocimetry (PIV) has proven to be a very useful technique in mapping animal-generated flows or flow patterns relevant to biota. Here, theoretical background is provided and experimental details of 2-dimensional digital PIV are explained for mapping flow produced by or relevant to aquatic biota. The main principles are clarified in sections on flow types, seeding, illumination, imaging, repetitive correlation analysis, post-processing and result interpretation, with reference to experimental situations. Examples from the benthic environment, namely, on filter feeding in barnacles and in bivalves, illustrate what the experiments comprise and what the results look like. Finally, alternative particle imaging flow analysis techniques are discussed briefly in the context of mapping biogenic and biologically relevant flows.