Getting an accurate reading of how much a whale weighs can be very problematic.
Because of their large size and penchant for staying in ocean waters, the only way to get an idea of the body mass of whales is to weigh them once they died or are stranded.
That way of determining body mass has limitations. For one thing, scientists aren't able to collect longitudinal data over the lifespan of the whale. The assessment can also be inaccurate because of bloating and deflation in the deceased whale.
Drones used to get an accurate reading of whales body mass
But technology, more precisely drones, have changed that. Researchers led by Fredrik Christiansen, an assistant professor at Aarhus Institute of Studies in Denmark, took photographs by drones of southern right whales and by measuring the body length, weight and height, were able to calculate the body mass. Their work was published in British Ecological Society.
"Knowing the body mass of free-living whales opens up new avenues of research," said Christiansen in a press release highlighting the research work. "We will now be able to look at the growth of known aged individuals to calculate their body mass increase over time and the energy requirements for growth. We will also be able to look at the daily energy requirements of whales and calculate how much prey they need to consume."
Accurate reading of whales weight can glean more information
Accurately determine the weight of live whales at sea is important because it can gauge how chronic stressors impact the whales' ability to survive and enable accurate sedative dosing of the whales that get ensnared in fishing gear. The researchers noted the model is being used to determine what if any impact kelp gull harassment has on the health and survival of southern right whale calves.
"The use of drones to estimate whale weight and condition, as well as to individually track calves while they grow beside their mothers, has been a real breakthrough in our investigation," said Dr. Mariano Sironi and Dr. Marcela Uhart from the Southern Right Whale Health Monitoring Program and co-authors of the study. "The use of drones to estimate whale weight and condition, as well as to individually track calves while they grow beside their mothers, has been a real breakthrough in our investigation."