Underwater Sounds Recorded in Glacier Bay
Notes on Sound Clips
The recordings available here were made by the National Park Service, using a hydrophone that is anchored near the mouth of Glacier Bay, Alaska for the purpose of monitoring ambient noise. The recordings are intended to provide examples of the types of natural and manmade sounds that occur in Glacier Bay National Park. Most of the samples are 30 seconds long, but some are longer or shorter. Recordings are available as files, of various sizes ranging from 94 to 650 KB.
To listen to these sounds you must have an MP3 reader, some of which are available for free on the web.
Important Note on Apparent Loudness of Samples
Listeners should not conclude that the sound source in one sample was truly louder than another just because one recording sounds louder. These samples were taken with the recording equipment set at various ‘gain’levels, and the subjects were at various distances from the hydrophone; therefore, the loudnesses of samples are not comparable.
Click on the headings below to see a list of sound clips. See below for important notes on various types of recordings.
Humpback Whale (Megaptera novaeangliae)
Feeding call is a sterotyped vocalization typically used during humpback whale coordinated group feeding. In the Glacier Bay area, it typically occurs 15-20 seconds before a group of whales all surface together after a foraging dive. This specialized call is common in some localities but rare in others. It may be used for group coordination, (ready, set, go!) or to scare/concentrate the schooling fish that are their prey.
Unstructured sounds. The most common humpback whale vocalization in Bartlett Cove was the simple “whup”, made with no discernable pattern. The track entitled “moo etc”is a sample of common humpback whale vocalizations on a somewhat windy day. Whales can also make non-vocal sounds by slapping their tail, flippers or other body parts on the water (for example during a breach). These sounds can carry for hundreds of meters and seem to provide another way for whales to communicate with one another over distance. As you will hear twice near the end of the cut titled “wheezeblow etc”, even the whale’s breathing can be audible at some distance, especially wheeze blows.
Killer Whale (Orcinus orca)
Both residents and transients use discrete calls, whistles, and clicks. Calls and whistles are used only in social communication, while clicks are predominantly used in echolocation. A clicking killer whale produces high frequency sounds and uses the echoes of those sounds to form images of the areas around him or her. In much the same way that humans use sonar to investigate the seafloor, the ultra-structure of certain materials, or medical views of the inside of our bodies, whales use echolocation to orient and find food in an environment where lighting conditions are poor. Based on differences in usage of calls, whistles, and clicks, researchers can tell whether the whales are foraging, resting, or socializing.
For more details on killer whale vocalizations and other features of their biology, please visit the following sites:
For more information on the functions of harbor seal vocalizations, visit the following site:
Other Animal Sounds
Did You Know?
Since the early 1990's, the sea otter population in Glacier Bay has grown from 0 to 4,000. Look for large rafts of sea otters in the lower reaches of the bay.