Tracking Marine Mammals in 3D

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Tracking Marine Mammals in 3D

Many marine mammal species are remarkably deep divers. Beaked whales, sperm whales, and elephant seals regularly dive to depths greater than 1 km, and some species, such as the Cuvier’s beaked whale, have been recorded at depths of 3 km on a single breath that lasted over two hours! We know very little about these species other than that they are diving to great depths to exploit unique food resources that are not available in other areas. Their foraging strategies, energy expenditure, and communication at depth are all mysteries that scientists seek to learn more about.

Marine mammals are difficult to study because they spend the majority of their lives underwater, and away from the surface where they are easily available for observation. There are two main techniques that scientists use to study marine mammals at depth: passive acoustic monitoring and archival tagging.

Passive acoustic monitoring is a simple system for detecting, monitoring, and sometimes localizing marine mammals at depth by recording their vocalizations with a hydrophone. Archival tags are small tags that are attached to the animal to record fine-scale movements (ex. direction, roll, pitch, speed) and environmental data for the surrounding water column including depth, temperature, and salinity. The data recorded by these two systems are complimentary, and as a result, are often collected at the same time to provide a wide breadth of information on animal behaviour.

Our colleagues at CREEM are experts in analyzing these types of data and have developed numerous techniques for calibrating and deploying these systems. Be sure to check out their most recent blog post on their approaches for tracking and modeling marine mammals in 3D.

[media-credit name=”Pierangelo Pirak (BBC Earth)” link=”http://www.bbc.com/earth/story/20150115-extreme-divers-defy-explanation” align=”alignnone” width=”727″]Deep diving marine mammals[/media-credit]

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2 Comments

  1. John Toby October 24, 2015 at 7:09 pm

    Just plain incredible capacity! It would be nice to find out the actual difference in pressure (this can be calculated, all right ?) but also certainly how their organs can adjust and withstand the fast change. Especially since the human divers body needs so much time to adjust.

  2. Cormac Booth October 28, 2015 at 8:31 am

    Yes, it’s certainly an amazing adaptation. One thing that has fascinated me is how air-breathing mammals can cope. A couple of amazing features they have is that they force all of the oxygen into their muscle tissues when they dive which assists them. They also enter brachycardia where they suppress their heart rate down to 10% or less of their normal heart rate at the surface, but still being very active at depth (feeding, moving, lunging etc.)!

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