Persistent observations of large underwater animals are difficult to achieve without the help of electronic, multi-sensor tags. Data obtained from these sensors provide important insight into the biomechanics, activity patterns, energy expenditure, diving and mating behaviors of these animals, which are otherwise "foreign" to the scientists who study them. In particular, there has been little work done on large reef fish such as the Atlantic goliath grouper (Epinephelus itajara), whose behaviors have been poorly described despite being a common inhabitant of many of Florida's offshore reefs and wrecks. Researchers from Florida Atlantic University's Harbor Branch Oceanographic Institute and College of Engineering and Computer Science are the first to reveal detailed behavior of this grouper species, which can reach lengths of 8 feet and weigh more than 800 pounds. To accomplish this task, they developed a novel multi-sensor tag that includes a three axis accelerometer, gyroscope and magnetometer (collectively referred to as an inertial measurement unit or IMU) as well as a temperature, pressure and light sensor, a video camera and a hydrophone for monitoring underwater sound.

The North Atlantic Right Whale (Right whale) is one of the most endangered whale species in the world with only about 368 remaining off the east coast of North America. A decreasing trend and low reproduction rates, combined with high levels of human activities – such as shipping and fisheries – underscore their precarious situation. Efficient tracking of their numbers, migration paths and habitat use is vital to lowering the number of preventable injuries and deaths and promoting their recovery. One of the frequently used methods to monitor whales is called passive acoustics technology. Right whales vocalize a variety of low-frequency sounds such as moans, groans, pulses and even belches.