Dolphin Wearables Support Marine Research and Conservation
December 29th, 2022
Via Futurity, a report on how new wearable sensors for dolphins could reveal the cost of human disturbances in marine habitats:
Human disturbances in dolphin habitat include climate change, overfishing, and noise pollution from construction, oil exploration, and navy sonar activity. These disturbances can interrupt important animal behavior like foraging for fish and socializing, but measuring disturbance is difficult under water.
Devices very similar to fitness trackers used by humans—known as biologging tags—are used in biology research but estimating the energetic cost of swimming has been challenging. With custom biologging tags, the engineers now are able to measure animal movement during thousands of strokes as they swim.
“Our goal is to use tag data to estimate foraging events, how many fish were consumed during a day, and connect that to estimates of how much energy dolphins use during the movement required to catch those fish,” says Alex Shorter, assistant professor of mechanical engineering at the University of Michigan and senior author of a paper in the Journal of Experimental Biology on the work.
“This is important for conservation because we can then use our approach to estimate energetic costs when these animals are disturbed.”
In the new work, the researchers developed estimates of energetic cost from tag data by working with their human and animal collaborators at Dolphin Quest Oahu. In that environment, the researchers could conduct repeatable swimming trials over a range of speeds from multiple animals to generate the data they needed to estimate how much energy the animals used as they swam. Marine mammal specialists trained the dolphins to wear the tracker during lap trials and periods of free swimming.
The tag sits between the blowhole and dorsal fin of the dolphin, attached with suction cups, where it noninvasively measures speed, temperature, pressure, and movement. Six dolphins participated in the work, and just as in data collection with humans, the animals were free to decline to participate in the work at any time.
During the prescribed lap trials, the animals started from rest at a floating dock and swam an 80-meter lap underwater around one of the marine mammal specialists and back to the dock at speeds of up to 21 kilometers per hour (13 miles per hour). During free swimming, in which the dolphins received no instructions, tags tracked movement for periods that ranged from 9.5 to 24 hours. One of the dolphins tracked for a 24-hour period swam over 70 kilometers (43.5 miles), and these data were used for a case study of daily activity and energetic cost for a bottlenose dolphin. Importantly, these findings can extend to tag data from animals in the wild.
“Our tag-based method is universally applicable to both animals in managed and wild settings, and can lead to a host of new research in monitoring the physical well-being of dolphin populations, which in turn will inform how we as humans are affecting their travel patterns, feeding requirements and lives in general,” says Joaquin Gabaldon, a postdoctoral researcher in robotics and first author of the study.
“From a technological perspective, it is our hope that other researchers see the potential of dedicated on-tag speed sensing, and pursue the development of more adaptable speed sensors to enable energetics monitoring for a wider variety of marine animals,” Gabaldon says.
Collaborators at Loggerhead Instruments, the Woods Hole Oceanographic Institution in Massachusetts, and Aarhus University in Denmark contributed to making the sensors.
The study had support from the Office of Naval Research, the National Science Foundation, the Department of Fisheries and Oceans Canada, and the University of Michigan.
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Read More »Park Rangers Are Using Silent Ebikes to Catch Poachers
December 7th, 2022
Via Wired, a look at how a Swedish electric bike is helping Mozambique’s park rangers protect game and reducing the need for fossil fuel infrastructure in Africa’s remotest areas:
AT THE END of 2021, a group of night poachers in a Mozambique national park—using torchlight to blind antelopes—were suddenly the ones left stunned in the dark. The poachers, local opportunists looking for bushmeat in the area’s savannahs, forests, and wetlands, are often able to kill hundreds of animals in one hunt with near impunity, using dogs to track and finish off their prey. They move with confidence because they can hear the noisy petrol motorbikes of the overstretched rangers from more than a mile away, enabling them not only to escape, but also to know where the park’s guardians are and hunt around them—easy enough to do in the thousands of square miles of terrain.
Not this time. A team of rangers silently moved in on their off-road ebikes, halting the hunt immediately. The nearly silent motor of the ebike—a factor that can make them an accident risk in the busy city—has become the surprise secret weapon for saving the world’s most endangered species.
“The petrol bikes we’ve used previously have all been loud, heavy, and expensive to keep running in these areas. These bikes are quiet, which makes it easier for us to approach poachers undetected,” says Mfana Xaba, anti-poaching team leader of Southern African Wildlife College (SAWC), a nonprofit organization based near South Africa’s Kruger National Park. It supplies trained rangers to 127 parks across Africa, including the one in Mozambique. (The exact locations where they are using the bikes is being kept secret, for fear of compromising the mission.)
Several poaching attempts have been stopped this year already, saving a variety of animals, including tiny antelopes—suni, red duikers, and blue duikers—which poachers kill in huge numbers for bushmeat. While these species are not classed as “at risk” themselves, they form an essential part of fragile ecosystems on which endangered animals rely, says Alan Gardiner, an ecology professor and head of the Applied Learning Unit at SAWC. “Suni and the other small antelope form prey items for many predators such as leopards, crowned eagles, and pythons, as well as influencing vegetation growth. When any species is impacted in a system it has a knock-on effect.”
Fifty Kalk Anti-Poaching bikes, made by the Swedish company CAKE, will now be used across SAWC’s African parks, after being tested across the continent’s varied terrain, including plains, forests, and jungle. “The previous petrol bikes were immensely problematic, and not just because of the noise,” says Stefan Ytterborn, CAKE’s founder and CEO. “The petrol to power them has to be brought in using trucks or even helicopters, which is extremely inefficient. As you have to store gas in the jungle, the petrol can then be stolen either by poachers themselves or local people who need it.”
CAKE already produced an existing recreational off-road ebike, and it teamed up with SAWC when the college realized the quiet, durable bike could be revolutionary in Africa’s varied topography. After some tweaks, the Kalk AP was sent to Africa. It weighs 80 kilograms (176 pounds) and can reach speeds of 56 miles per hour, with around five hours of ride time. CAKE switched its standard tires for 18-inch off-road tires like the ones used in motocross, and supplied a software system providing navigation, communication, and location identification, enabling CAKE to retrieve vehicle data and continue to monitor and improve each bike’s performance.
Solar-powered mobile charging points mean rangers can camp in the bush for weeks. The charger, called the Goal Zero Solar Hub, can charge at least two bike batteries from empty to full in just three hours, and it takes 18 hours to charge itself from zero using the sun’s rays. “The charging points are a bit heavy—45 kilograms—but they can be pulled around on their built-in wheels like a suitcase,” says Ytterborn. “That means that at every station, there is a fresh battery on charge and ready to be swapped to the one on the motorcycle.”
This longevity means the rangers can disappear in teams of up to three to track poachers for several weeks, and spend longer embedded in rural communities, educating and supporting locals who often turn to poaching because they are desperate for food or money. Rangers currently distribute food vouchers and cash to dissuade locals from eating certain animals.
The Kalk AP bikes—which cost around £9,900 ($11,800)—will eventually be used across the continent, helping to protect Africa’s most endangered animals, such as the white and black rhinos that are attacked by professional, organized gangs seeking profits. Kruger National Park has lost almost 70 percent of its rhinos this decade, including 166 rhinos poached during the first six months of 2020.
Mfana Xaba, who has overseen the rangers in the field in Mozambique, believes the ebike will finally give them an edge on the persistent poachers. “Meat poachers are constantly trying to penetrate our area—hundreds of thousands of acres—and the poachers are very good at hiding. The element of surprise is very important. Forests and wetlands are the most difficult terrains for us to cross, but the silence of the bikes is by far and away their greatest attribute, as well as their very low running costs.”
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