Thanks for all those following the SOCAL-12 blog and for all the queries about how we are doing out here. Sorry for the radio silence the past few days but we have been way offshore and taking advantage of good weather in deep waters around San Clemente, San Nicholas, and Santa Catalina. We have had some ups and downs with weather, equipment, and animals, but we have managed to get some really great and some new things accomplished. Below is a picture of four (in a group of six) Baird’s beaked whales (Berardius bairdii) we found on the Navy listening range off San Clemente a few days ago (photo credit: T. Pusser; this and all below photos taken under NMFS permit#14534-2).
You can see a small gold-colored suction cup acoustic tag attached to the individual on the far left just forward of the dorsal fin. This is the first individual of this species tagged with a high resolution suction cup sensor that monitors diving and acoustic behavior. We tagged the animal around mid-day and came extremely close to tagging a second individual as well. We followed the animals for four hours collecting baseline data on the tag augmented with focal follow behavioral data from a small tag boat. Later in the afternoon we conducted the first experimental behavioral response study ever done on this species. Recovering the tag the next day turned into quite an adventure with some wild weather and island excursions to get higher elevation so we could hear the tag beacon more clearly. But with some teamwork and some help we managed to recover it and are currently processing the extremely valuable data it contains. Beaked whales are our highest priority group of species because they clearly appear more sensitive to human sounds than other marine mammal species. Our project and related efforts have conducted controlled exposure experiments with other beaked whale species that have been involved in previous stranding events associated with military sonar, but this is the first with this species. They are particularly interesting to compare to previously-tested species because, based on somewhat limited information, they have somewhat different characteristics, including larger body size, larger group size, and apparently different social interactions (including more communication whistles). The data from this tag will provide valuable information about both their basic diving and acoustic behavior and the first direct measurements of their responses to known sound exposures.
Baird’s beaked whales (courtesy Cascadia Research, J. Calambokidis; G. Schorr)
Another first for us was to obtain some direct measurements of behavioral responses of transient killer whales (Orcinus orca) to controlled sound exposures. We found a group of these mammal-eating animals also off San Clemente and included them in our study this year. We tried to attach a suction-cup acoustic/diving tag to them but weren’t quite able to (see below photo: credit Cascadia Research, E. Falcone).
However, this group of six orcas was included in one of the controlled exposure experiments with behavioral data on their movement and group composition obtained from a small boat focal follow. This isn’t as optimal as having the animals tagged, but does provide some important experimental results on this species. These data will be particularly important to consider in light of some related studies on fish-eating orcas in Norway. We hope to find and tag other orcas in SOCAL-12, as they are apparently relatively plentiful in southern California at the present time.
We have also been able to get suction cup tags attached to bottlenose dolphins (Tursiops truncatus) as well in SOCAL-12, including the below individual tagged this morning with Santa Barbara Island in the background (photo credit E. Falcone, taken under NMFS permit #14534-2).
Getting these kinds of tags to stay on the smaller odontocete (“toothed cetaceans”) species has proven challenging previously and our deployments have been successful but similarly short unfortunately. We will likely focus our efforts on some of these species using visual sampling methods without tags, as we did for the orcas.
We may well be offshore again the next few days but will get updates as possible about our progress. We are a little more than halfway done with the first of three phases of SOCAL-12 and have already tag