According to the journal Marine Environmental Research San Diego sea
lions also react to underwater sonar. Younger sea lions react even more heavily
to sonar sounds. According to the study, 15 captive sea lions reacted in
varying ways. As they were swimming across the pool to hit a paddle the bursts
of sonar forced them to change their heart rate, stay deeper underwater or jump
out and stay on land. Some simply refused to finish their routes or participate
anymore.
The Navy is seeking to collect and understand more about the
sparse information available about wildlife as it relates to military
activities. In this case, the sonar test is helping them understand both the
capabilities as well as the impact of underwater sound waves. So far the use of
tactical sonar signal (1 s duration, 3250–3450 Hz) has a noticeable impact
on this species.
What is the benefit of this research? Certainly it is nice
to know if there is a damaging impact on sea life and if adjusting the
frequency lowers the risk. In addition, such research may help us learn about
the capabilities of sea life. Robotics is taking special interest in trying to
mimic wildlife capabilities in man made equipment. Doing so raises the level of
technology available for both civilian and military purposes. At present the
study is limited to impact alone.
Houser, et. al. (2013). Behavioral responses of California sea
lions to mid frequency (3250–3450 Hz) sonar signals. Marine Environmental Research, 92. http://www.sciencedirect.com/science/article/pii/S0141113613001797
Other Reading:
