Oct 24: Echo Sounder

Posting by VIMS post-doctoral researcher Kim Bernard.

Our echo sounder, or DT-X as its manufacturer Biosonics call it, sends sound waves out at a frequency of 120 kilohertz (kHz). The sound waves bounce off animals, like krill, in the water and return to the echo sounder. The acoustic returns are logged and later analyzed.

The data we get from the echo sounder allow us to figure out what is in the water and how much of it is there. For every acoustic return we have a date and time stamp as well as latitude and longitude coordinates.

Our target animal is the Antarctic krill (Euphausia superba), and we are trying to understand what drives its distribution patterns and densities near Palmer Station. One of the reasons we are interested in this is because the Adélie penguins that breed on the islands here feed on Antarctic krill.

An echogram showing an aggregation of krill—this is what we will be looking for when we head out on our Zodiac!

Author: David Malmquist

David Malmquist is the Director of Communications at the Virginia Institute of Marine Science, College of William and Mary.