Certain skills and knowledge are required to work effectively as a Marine Mammal Observer (MMO) and Passive Acoustic Monitoring (PAM) Operator. The Marine Mammal Observer and Passive Acoustic Monitoring Handbook covers all elements in details, but included here are guides for estimating bearing, and for calculating range to sighting, using either reticle binoculars or a range stick.
An understanding of marine mammal distribution is also important, regional distribution tables (in English) for marine mammals are available on the publications page, and for freshwater mammals here.