New tag to help study whale behavior, marine environment

A new type of tag, known as "Advanced Dive Behavior," or ADB, can record data every second for weeks at a time to provide a view of whale behavior, biology and travels deep beneath the sea, over thousands of kilometers and their interaction with the prey.

In a study published in the journal Ecology and Evolution, researchers with Oregon State University (OSU) outlined the continued evolution and improvements made in the ADB technology from 2007-15, in which it was used on sperm, blue and fin whales.

Findings from data collected by the tag showed, among others, sperm whales diving all the way to the sea floor, more than 1,000 meters deep, and being submerged for up to 75 minutes; and baleen whales lunging after their food.

"By using this technology on three different species, we've seen the full range of behavior that is specific to each species," said Daniel Palaciosa, co-author on the study. "Sperm whales, for instance, really like to dive deep, staying down a long time and appearing to forage along the seafloor at times. During summer the baleen whales will feed as much as possible in one area, and then they move on, probably after the prey density gets too low."

The tag, according to the researchers, expands by several orders of magnitude the observations that can be made of whale feeding and behavior, and it is showing what whales do while underwater; when, how and where they feed; how they might be affected by passing ships or other noises; and what types of water temperatures they prefer.

Unlike earlier technology that could not return data from the deep sea for much longer than a day, ADB tags are designed to acquire data constantly, for up to seven weeks at a time, before they detach from the whale, float to the surface and are retrieved in the open sea to download data. The retrieval has worked well as the tags would transmit global positioning system (GPS) locations and flash light-emitting diode (LED) lights once they have released.

"With this system we can acquire much more data at a lower cost, with far less commitment of time by ships and personnel," Ladd Irvine, the corresponding author on the study, was quoted as saying in a news release from OSU. "This tag type yields amazing results. It's going to significantly expand what we can accomplish, learning both about whale ecology and the ocean itself."

The tag can sense water depth, whale movement and body orientation, water temperature and light levels.

"This technology has even made whales our partners in acquiring data to better understand ocean conditions and climate change," said Bruce Mate, professor and director of OSU's Marine Mammal Institute in the College of Agricultural Sciences. "We're learning more about whales, and the whales are helping us to learn more about our own planet." Endit