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April 15, 2013
Volume 2, Issue 15

Computers Help Save Whales

We don't usually think about wildlife when we think about computer science- but did you know that computer science is being used to help save an endangered species?

Northern Right Whale

A northern right whale (image from Moira Brown/New England Aquarium via wikimedia)

The northern right whale was hunted to the brink of extinction because of the commercial demand for the oil extracted from its blubber. Once tens of thousands strong, their population has dwindled to approximately 350, of which only 70 are believed to be females capable of reproduction. While the endangered species is now protected against hunting, it faces another threat: fatal collisions with ships. In particular, the Stellwagen Bank, a crucial feeding ground located at the mouth of the Massachusetts Bay, is crossed by a heavily-used shipping lane leading to Boston.

The northern right whale makes distinctive sounds, with a unique combination of pitches. This has allowed researchers to combine microphones, sound-recognition software and cell phones to detect the whales and alert ship captains, allowing boats to slow down and steer clear if their paths come close.

Grapraphic range of northern right whale

Geographic range of the northern right whale

Strategically placed buoys are equipped with underwater microphones, a radio telemetry system and an on-board computer with acoustic analysis software. This software converts the sound picked up by the microphone into a frequency spectrum, that is, a map of intensities of different pitches from which underwater noise can be filtered out. The map can then be compared to a database of recorded right whale sounds. When the computer finds a match, the recording is sent via cell or satellite phone to an analyst, who verifies the presence of whale sounds, posts the detection to a website and sends warnings to ships in the area.

Ship captains receive the warnings and monitor the location of the whales through a mobile app called WhaleALERT. The buoys operate continuously and analyze sounds as they are detected. Each has a detection radius of approximately five nautical miles, and together they cover a 55-mile stretch of the commercial shipping lanes leading to Boston Harbor. Notification can occur within 20 minutes of the initial detection.

In addition, scientists have developed underwater robots, called gliders, that work the same as the buoys except they move around autonomously underwater. The gliders can stay at sea for weeks at a time, listening for whale sounds. They periodically surface to check their locations using GPS, upload data and receive instructions. The researchers plan to integrate the information generated by the gliders into the Stellwagen warning system.

Thom Dunning

Susan Parks of Syracuse University with two whale-listening buoys. (Photo from Syracuse University)

Who thinks of this stuff? A team of interdisciplinary researchers has worked together to implement this system. The software-equipped buoy system was collaboratively developed by the Cornell Lab of Ornithology’s Bioacoustic Research Program and the Woods Hole Oceanographic Institution. The Bioacoustics Research Program is led by Professor Christopher W. Clark, who has a background in both electrical engineering and biology. Susan E. Parks, a professor of Biology at Syracuse University, has used the buoy system to study whale sounds in the wild. Mark Baumgartner and Dave Frantantoni of the Woods Hole Oceanographic Institution developed the underwater robots. The WhaleALERT app was developed at the Stellwagen Bank National Marine Sanctuary, which is administered by the National Oceanographic and Atmospheric Administration.

 

 

Links:

It's whale migration season! See where whales have been detected in the Stellwagan Bank at the Right Whale Listening Network: http://www.listenforwhales.org

Read more about the WhaleAlert App: http://stellwagen.noaa.gov/protect/whalealert.html

Learn about research into right whales at the New England Aquarium: http://www.neaq.org/conservation_and_research/projects/endangered_species_habitats/right_whale_research/index.php

Read about Mark Baumgartner’s research at Woods Hole: http://www.whoi.edu/sbl/liteSite.do?litesiteid=5252

Check out where people have recently sighted right whales: http://www.nefsc.noaa.gov/psb/surveys/

More information about right whale migration can be found here: http://www.whaleroute.com/migrate/

Activity

Visit the Listen for Whales website. You will see a map of the Massachusetts coast, including the Stellwagan Bank. The chain of 10 buoys that covers 55 miles of shipping lanes is indicated as a series of dots. Each buoy has a "listening range" of five nautical miles, indicated by the larger circles. If a buoy has detected a right whale within its listening radius in the last 24 hours, a red whale graphic is superimposed over the buoy. Note that some of the buoys may currently be "offline," or inactive. The Explore Whale Sounds page explains how the buoys are able to detect whale calls. As a class or in small groups, look at the map and the whale sound frequency spectra, and discuss the following questions.

Questions:

  1. How many whale calls have been detected in the past 24 hours? At how many buoys? Is this information enough to determine the number of whales that are present in the shipping corridor pathway?
  2. If each right whale call detected came from a unique whale, what fraction of the total remaining population has been within the listening zone? Is it possible that only one whale is responsible for all detections?
  3. There is some overlap between the listening radii of adjacent buoys. Could this be used to more precisely identify a whale’s location? What information would be needed to pinpoint a whale’s location?
  4. What are the advantages of a buoy’s computer system analyzing sounds as they are detected, rather than simply broadcasting all recordings for humans to listen to back at the lab?
  5. What else might scientists want to learn about the northern right whales? How could the buoy and alert system be used to help? How might you adapt the system or the computer program to learn even more?