At the top of our list of objectives for SOCAL-BRS is to obtain direct measurements of the responses of beaked whales to simulated military sonar. Yesterday we had remarkably fair seas (as in zero wind for almost the whole day), which are the conditions required for tracking these elusive animals. Yesterday we got it and were able to find and track beaked whales 60 miles offshore all day. Early in the morning we found a group of three Cuvier’s beaked whales (Ziphius cavirostris), that became five and then eight animals, with another pair spotted on the horizon. By midday we managed to attach a version III D-tag for monitoring movement and sounds produced and received by the animals on an individual beaked whale (the tag can be seen riding on the whale in the picture below, taken by A. Friedlander under NMFS permit #14534).
Cuvier’s beaked whale with an acoustic monitoring tag off southern California
Beaked whales are some of the most extreme animals on the planet, repeatedly doing long and deep dives. We also have specific protocols for conducting controlled exposure experiments (CEE) to ensure the safe execution of the study and also sufficient baseline data against which to statistically compare potential responses. The combination of these factors generally means that, even after the extreme challenge of tagging one of these animals, successfully completing a full exposure sequence can be difficult and takes a lot of patience. Fortunately we managed to follow the group yesterday for over ten hours with a combination of acoustic monitoring, visual monitoring, and tracking of the VHF transmission from the tag. Near the end of the day we successfully completed a CEE with the tagged Cuvier’s beaked whale.
Today was spent in MUCH rougher conditions recovering the tag and getting back to the mainland. We put a lookout on top of Santa Barbara island to listen for the tag transmission and direct the boats spread out to track down the tag. While it was a little bumpy, it worked and we got the tag and all the data loaded onto it back. There was much rejoicing. The offshore weather forecast looks pretty tough for the next few days so we will likely be coastal and back in baleen whale mode the next few days, but this is why we have options.
A group of Cuvier’s beaked whales swimming in calm seas