For wild sockeye salmon, the trip upriver from the ocean to their spawning grounds is fraught with peril and hardship. But quantifying exactly how obstacles along the way, fluctuations in water temperature and other factors impact fish survival has long eluded researchers. New advances in biological sensor tags are now allowing scientists to precisely measure animals’ energetics, their interactions with humans, and their responses to rapidly changing environments.
In 2014, for example, Nicholas Burnett and colleagues used accelerometer tags to measure how salmon needed to swim in order to traverse a dam in the Seton-Anderson watershed of British Columbia, Canada and how likely they were to survive the remainder of their journey. They found that when salmon resort to strenuous anaerobic swimming, they were significantly more likely to die days or even hours later.
For wild sockeye salmon, the trip upriver from the ocean to their spawning grounds is fraught with peril and hardship. But quantifying exactly how obstacles along the way, fluctuations in water temperature and other factors impact fish survival has long eluded researchers. New advances in biological sensor tags are now allowing scientists to precisely measure animals’ energetics, their interactions with humans, and their responses to rapidly changing environments.
In 2014, for example, Nicholas Burnett and colleagues used accelerometer tags to measure how salmon needed to swim in order to traverse a dam in the Seton-Anderson watershed of British Columbia, Canada and how likely they were to survive the remainder of their journey. They found that when salmon resort to strenuous anaerobic swimming, they were significantly more likely to die days or even hours later.
In “Utility of biological sensor tags in animal conservation,” an article in the current issue of Conservation Biology, Wilson et al. (2015) survey the use of biological sensor tags and make the case that such tools deserve a central place in the conservation toolbox. Other tags, including biotelemetry and biologging tags, are already widely used and have helped researchers understand where and how animals move. But as a new, versatile generation of sensor tags become used more broadly and are adopted in a broader array of species, they could deepen our understanding of how animals interact with the environment and shape wildlife-management policy and decision-making.
Here are answers to a few questions about sensor tags:
Why use them?
Wilson et al. (2015) highlight four areas of conservation where biological sensor tags are most useful: for “quantifying the impact of human disturbance on wild animals; understanding and predicting the impact of environmental change; understanding the consequences of habitat selection and animal movement; and implications for animal energetics.” For instance, one research group used heart-rate monitors shaped like eggs to measure how ecotourism affected stress levels in breeding yellow-eyed penguins. Another group tracked the movements and body temperature of Arabian oryx (Oryx leucoryx) to examine how the antelope might respond to climate change. Researchers have also used accelerometers to show that some turtles search for warmer water to hasten the development of their eggs. Finally, researchers could monitor birds’ heart rate and wing beat frequency to determine the energetic cost to birds detouring around human-made obstacles in a flyway.
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Sockeye salmon image via Shutterstock.
