images
Just as a smartwatch can tell its wearer how many calories they burn during exercise, data from dolphin wearables can now be used to estimate how much energy dolphins use when they swim.
University of Michigan engineers, in collaboration with marine mammal specialists from Dolphin Quest Oahu, have led the development of wearable sensors for marine mammals to monitor movement and behavior to improve marine conservation efforts. ‘these animals.
Dolphins and other sea creatures are affected by human disturbances in their habitat, including climate change, overfishing, noise pollution from shipping, construction, oil exploration and marine sonar activity . These types of disturbances can disrupt important animal behavior, such as foraging for fish and socializing, but measuring disturbances is difficult because the animals live underwater.
Devices very similar to the fitness trackers used by humans, known as biologging tags, are used in biology research, but estimating the energy cost of swimming has been a challenge. Now, with custom biologging tags made in collaboration with Loggerhead Instruments, the Woods Hole Oceanographic Institution in Massachusetts, and Aarhus University in Denmark, Michigan engineers are able to measure the animals’ movement over thousands of strokes as they swim. .
“Our goal is to use tag data to estimate feeding events, how many fish were consumed in a day, and connect that to estimates of how much energy the dolphins use during the movement required to catch those fish,” he said. Alex Shorter, assistant professor at UM. in mechanical engineering and lead author of an article in the Journal of Experimental Biology. “This is important for conservation because we can then use our approach to estimate the energy costs when these animals are disturbed.”
In their new work, the researchers were able to develop energy cost estimates from tag data by working with their human and animal collaborators on Dolphin Quest. In this unique environment, the researchers were able to conduct repeatable swimming tests at a range of speeds on various animals to generate the data needed to estimate the amount of energy the animals used while swimming. Marine mammal specialists trained the dolphins to wear the tracker during lap tests and free-swimming periods.
The tag sits between the hole and the dolphin’s dorsal fin, attached with suction cups, where it non-invasively measures speed, temperature, pressure and movement. Six dolphins participated in the work, and just like the data collection with humans, the animals were free to refuse to participate in the work at any time.
During the prescribed lap tests, the animals started from rest on a floating dock and swam an 80-meter underwater lap around one of the marine mammal specialists and returned to the dock at speeds of up to 21 kilometers per hour. During free swimming, in which the dolphins were not instructed, the tags tracked movement for periods ranging from 9.5 to 24 hours. One of the dolphins tracked over a 24-hour period swam more than 70 kilometers, and this data was used for a case study of daily activity and energy cost of a bottlenose dolphin. Importantly, these findings can be extended to tag data from animals in the wild.
“Our tag-based method is universally applicable to animals in both managed and wild environments, and may lead to a range of new research into monitoring the physical well-being of dolphin populations, which in turn will inform how humans are affecting their travel patterns, food requirements and lives in general,” said Joaquin Gabaldon, a postdoctoral researcher in robotics and first author of the study.
“From a technology perspective, we hope that other researchers will see the potential of tag-dedicated velocity sensing and pursue the development of more adaptable velocity sensors to enable energy monitoring of a wider variety of marine animals Gabaldon said.
This work dovetails with two of Shorter’s other projects related to dolphin conservation. He and Bogdan Popa, UM assistant professor of mechanical engineering, are studying how dolphins use echolocation to capture fish and images of their environments. In addition, the current work led by researchers from Duke University and the Oceanographic Foundation of Valencia, in collaboration with Dolphin Quest, aims to estimate the energy used during swimming by measuring movement and oxygen consumption.
The study was supported by the Office of Naval Research, the National Science Foundation, the Canadian Department of Fisheries and Oceans and the University of Michigan.
Study: Tag-based estimates of bottlenose dolphin swimming behavior and energetics. (DOI: 10.1242/jeb.244599)
Written by Makenzie Schlessman, Faculty of Engineering
/ Public communication. This material from the original organization/author(s) may be ad hoc in nature, edited for clarity, style and length. The views and opinions expressed are those of the author(s). See them in full here.