To be an effective Marine Mammal Observer (MMO) and/or Passive Acoustic Monitoring (PAM) operator certain knowledge and skills are required, including background knowledge of marine mammals and an ability to estimate range and bearing to a sighting. The Marine Mammal Observer and Passive Acoustic Monitoring Handbook explains everything in detail, but provided here are brief how-to-guides for some essential skills, and regional distribution tables of marine and freshwater mammal species and sub-species.

Distribution tables
	Regional distribution of marine mammal species
	Regional distribution of freshwater mammal species
Photo credit: Jim Kirklin	Regional distribution of freshwater mammal subspecies
Bearing estimation
	Bearing estimation
Range estimation
	Estimating range using a range stick
	Estimating range using reticle binoculars