Understanding Navigational Cues in the Marine Environment

I spent a hot afternoon in late July with the two Principal Investigators (PIs) on a new National Science Foundation (NSF) Ocean Technology and Interdisciplinary Coordination grant entitled “T-LEOST: realTime Larval Environmental and Ocean Signal Tracking: an integrated system for the study of navigational cues in the marine environment.” Instead of meeting in an office, we met by the pool at University of Miami’s main campus.

The goal was to test several new instruments that are part of this project. A drifting behavioral chamber developed by Dr. Claire Paris, one of the PIs, observes the behavior of fish larvae at sea using a camera and a compass system. The orientation the larvae take while tested inside the chamber reveals whether or not they are guided by certain navigational cues, such as a sun compass, odor, or sound.

With the new grant, we are making modifications to the existing chamber, allowing us to observe the behavior of fish in deeper waters, and in response to acoustic cues measured from reefs here in Florida.

To put the chamber into deeper waters and to de-couple it from the water surface, a motorized buoyancy device called the Medusa is being developed by Dr. David Mann of Loggerhead Instruments, the other PI on the grant. An essential step in the development process is to determine the natural rising and sinking

We also tested the capabilities of a pair of underwater speakers that will be mounted to the chamber to play back sounds of coral reefs to the fish. Recordings made in Florida with a hydrophone (developed by Loggerhead Instruments) will be played to fish in order to see whether they demonstrate orientation behavior towards these sounds. Reef soundscapes have been proposed as a cue that fish larvae may use during their journey from the pelagic environment to the reefs.

This is truly an interdisciplinary project, involving physics, biology, and engineering. Spending an afternoon with the experts was a great learning experience for me and we learned about the performance of our instruments in a controlled environment. Next step: the ocean!

Erica Staaterman
PhD Student, Applied Marine Physics & Marine Biology and Fisheries
Follow the Rosenstiel School on Twitter: @UMiamiRSMAS
“Like” the Rosenstiel School on Facebook: www.Facebook.com/Rosenstiel School
Circle the Rosenstiel School on Google+ : Rosenstiel School

Snap, Crackle, Pop: Listening to Florida’s Reefs

Erica Staaterman deploys underwater recording equipment produced by the Paris Lab. Photo by Evan D’Alessandro

My dissertation research addresses the question: do larval fish use reef soundscapes for navigation? But what is a “reef soundscape”? Well, if you have ever been diving or snorkeling, you have probably noticed an incessant crackling sound. This sound is primarily produced by snapping shrimp, one of the noisiest residents on a coral reef. But the soundscape consists of a wide variety of sounds, such as the growls, grunts, and pops produced by animals such as fish, lobsters, and crabs, as well as abiotic sounds such as the breaking of waves.

The first goal of my dissertation research is to describe the temporal and spatial changes in reef soundscapes. Through the use of long-term passive acoustic recorders, I am currently collecting a one-year time series of acoustic data from two coral reefs in the Florida Keys. This will allow me to determine the patterns that occur on daily, monthly, and seasonal scales. These data will later be used for behavioral experiments on fish larvae.

Listen to one of Erica’s recordings here. The snapping sound is being produced by snapping shrimp, and the low-frequency growl is most likely fish.

Erica Staaterman
PhD Student, Applied Marine Physics & Marine Biology and Fisheries
Follow the Rosenstiel School on Twitter: @UMiamiRSMAS
“Like” the Rosenstiel School on Facebook: www.Facebook.com/Rosenstiel School
Circle the Rosenstiel School on Google+ : Rosenstiel School