Listening in on the Underwater World

Underwater passive acoustic monitoring is a powerful tool for studying the lives of marine animals. This technique provides continuous information about underwater soundscapes and animal presence, complementing traditional methods of studying aquatic animal movements, residency, habitat use, communication and other behavior.

Since 2015, the SDRP has led collaborative efforts to better understand animal behavior and ecosystem health in and around the Sarasota Bay estuary using two sister acoustic monitoring networks. Together, these networks form the Sarasota PALS Network. PALS — which stands for “passive acoustic listening stations” — includes two complementary networks:

The Sarasota Bay Listening Network (SBLN) is made up of coastal hydrophones that continuously record underwater sounds produced by animals, human activities and physical events such as the weather. This network allows us to monitor sound-producing animals, including bottlenose dolphins, manatees and some species of fish and invertebrates.

The Sarasota Coast Acoustic Network (SCAN) is made up of an array of underwater receivers that monitor signals from tags on animals that may not produce sound — such as sharks, rays, fish and invertebrates. A tag’s transmitter is recorded by a receiver when a tagged animal swims near it. At periodic intervals, the research team retrieves the receivers, downloads the data, provides maintenance, and then returns them to the seafloor.

Did you know? A soundscape includes sounds produced by humans and animals, as well as physical events such as waves and rainfall.

An intern downloads data collected by an underwater receiver designed to “listen” for tags placed on marine animals. 

Impacts of the Sarasota PALS Network

  • Conservation Insights: The Network captures both the movements of marine species and the overall underwater soundscape. This dual approach provides a better understanding of animal behavior and habitat use, as well indications of ecosystem health. Long-term data collected via the Sarasota PALS Network are necessary for detecting trends in animal movements, distribution, relative abundance and behavior, which help inform conservation measures and policies.
  • Documentation of Disturbance Exposure and Response: The data we collect can reveal how marine animals are responding to disturbances and environmental changes that may negatively impact their ability to survive and reproduce. Disturbances of interest include natural events, such as heat waves, cold snaps, harmful algal blooms (e.g., red tides) and hurricanes, or those caused by humans (e.g., vessel traffic and marine construction).
  • Elevating Understanding Worldwide: Both SBLN and SCAN actively engage in collaborations with multiple scientific and conservation organizations, involving colleagues from around the world that contribute data to local and national initiatives, elevating the understanding of marine soundscapes and animal behavior.
  • Community Engagement and Education: The Network’s partnerships with educational institutions, research organizations and community organizations facilitate public outreach, student involvement and the development of educational curricula. This engagement not only communicates scientific findings but also fosters public awareness and enthusiasm for marine conservation.

Did you know? The Sarasota Dolphin Whistle Database contains 938 recording sessions of 302 individual dolphins.

We’re working with colleagues at Woods Hole Oceanographic Institution and the University of St Andrews to automate identification of these vocalizations using artificial intelligence (AI), which will help us identify the dolphins we record through the Sarasota Bay Listening Network! Click here to read a recent publication about this topic.

What We Hear at SBLN Stations

Animals Tagged and Tracked by SCAN

Bottlenose dolphins Spotted eagle rays
Florida manatees West Atlantic pygmy devil rays
Gulf toadfish Bull sharks
Spotted and sand seatrout Blacktip sharks
Hardhead and gafftopsail catfish Tiger sharks
Silver perch Sandbar sharks
Black drum Great and scalloped hammerhead sharks
Multi-species fish choruses Blacknose sharks
Snapping shrimp Striped and white mullet
Boat engine noise and marine construction Common snook
Noise from physical events, e.g. waves, rainfall Busycon whelks

Want to listen in to the underwater world? Click here!

The Sarasota PALS Network Research Partners

Help Support the Sarasota PALS Network!

You can make a contribution to the Brookfield Zoo Chicago in support of the Sarasota Dolphin Research Program. Click here to visit BZC now and select “Sarasota Dolphin Research Program” from the gift-designation drop-down menu. You may also contact Claire Broadhead, Major Gifts Officer, at 708.688.8667 or email

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