Underwater Robots Listen for Call of Endangered Right Whales
© Nadine Lysiak, Woods Hole Oceanographic Institution
There are currently fewer than 500 right whales remaining in the wild and boat collisions account for somewhere around one-third of all known deaths of these whales. Whaling initially devastated the species, but shipping is now their biggest threat.
Luckily, the endangered whales now have a high-tech line of defense against boaters and other human-related threats. Underwater robots developed by the Woods Hole Oceanographic Institute (WHOI) can hear the calls of baleen whales and then send location data back to researchers in real time. When researchers get back this information, they can then take action to protect the whales.
"We can use this information to very quickly draw a circle on the map and say, hey, we know there are whales in this area, let's be careful about our activities here. The government can then alert mariners and ask them to reduce their speed and post a lookout," WHOI researcher Mark Baumgartner told National Geographic News.
Just last month, two of the six-foot, torpedo shaped gliders used their digital acoustic monitoring equipment to detect nine North Atlantic right whales in the Gulf of Maine. On December 5, the gliders enabled NOAA's Fisheries Service to alert mariners of nearby whales in the Outer Falls, MA area.
© Cyndi Bowning, New England Aquarium
The gliders are programmed to recognize the calls of right, humpback, fin, and sei whales, but more species could be added to allow these gliders to detect all sorts of marine species. When the gliders hear the calls, they process and classify the acoustic signatures. Then every two hours the gliders come to the surface and transmit any data they've collected.
In addition to the acoustic monitoring equipment, the gliders are also outfitted with environmental sensors that collect data about things like temperature and salinity, and the estimated algae population levels, which are at the base of the marine food chain. Those levels give the researchers an idea of how much zooplankton is around the area that the whales could feed on. All of that data lets researchers not only see where the whales are, but why they're there.
The underwater robots boast a suite of environmental sensors to record temperature and salinity, and to estimate algae population levels at the base of the marine food chain. "They even have an instrument that gives us a crude sense of how much of the zooplankton that right whales feed on is in the area," Baumgartner said. "So they have an enormous capacity to help us understand not only where the whales are, but why they are there."
The robots can also be easily updated with software that has a larger "call library" so more whales can be identified by their calls as the sounds are collected and cataloged.
The best part of these new gliders has just been the huge improvement in being able to spot these animals, which is the best way to protect them. Before, NOAA and other groups would use ships and airplanes to go out and look for whales, but those expeditions were limited by weather conditions and what the human eye could see.
"I've worked on a number of projects where we just had great difficulty even finding the animals," Baumgartner said. "So it's a great feeling to have a capability like this that gives us some advance notice. Before we left the dock we knew that right, humpback, and fin whales were in our study area—and when we got there that's exactly what we found."