Hearing the call: using acoustics and citizen scientists to monitor harbor porpoises

There are many challenging obstacles involved in researching wild marine mammal populations. Finding the right combination of accurate and cost-effective research methods is crucial. The harbor porpoise is a shy, enigmatic species making traditional boat based methods of monitoring very difficult. The Pacific Biodiversity Institute (PBI) has initiated a unique program combining two emerging research tools, passive acoustics and citizen science, to monitor the harbor porpoise population in the inland waters of Puget Sound. A passive acoustic monitor (PAM) is deployed in water at Burrow’s Pass to allow researchers to continuously record cetacean presence in an area for months at a time by documenting vocalizations. To compliment this acoustic research instrument, PBI has trained many local residents to be Citizen Scientists and conduct land-based observations in Burrow’s Pass, documenting harbor porpoise presence, position and movement. This data complements the PAM data (supporting the validity and usefulness of the PAMs), and provides information about the population that cannot be collected by the PAM (such as movement patterns, group sizes and group composition). The acoustic data collected, combined with continued visual observations by citizen scientists, is used to assess diurnal, seasonal and annual trends in the harbor porpoise population. This type of long-term monitoring provides data that is vital to protection and conservation efforts. The involvement of citizen scientists also has the added benefit of fostering a sense of responsibility and care for the environment that facilitates science-society-policy interactions. PBI’s harbor porpoise research program combines PAM and citizen science to create an informative and cost-effective way to monitor a marine mammal population and can be used as a model for future studies on similar populations