Upcoming San Juan Island Orca Research Project
Hi Susan,
We wanted to let everyone know that we would be out for a few more weeks of field work off San Juan Island starting Wednesday September 6th, through about Friday the 22nd. This work will be using the same NOAA rigid-hulled inflatable with the bow pulpit that we’ve been using the last couple of years. As well as a continuation of the fecal and prey sampling work with southern residents, we are hoping to work with transients if they continue to use the area. One of the things we’d like to do is try to deploy one or more suction-cup attached time-depth recorders to examine the underwater and night-time behavior of transients. While we have a pretty good idea of what southern residents are doing at night and at depth from our previous tag deployments, we’ve only deployed six of these tags on transients in the past, with a total of about 51 hours of dive data (versus 400 for southern residents). There were some interesting similarities (for example less activity at night) and differences from residents (spending more time at mid-water depths but not diving as deep), but the sample size is too small to be conclusive. This work is quite relevant to the current debate regarding the impact of transient killer whales on various prey populations, as whether they are feeding at night as often as during the day has implications for food intake rates and potentially even seasonal movements of the whales.

If anyone has any questions about this work, there is a pdf of a publication on the diving work with residents available at www.cascadiaresearch.org/robin/kwindex.htm, or e-mail us at rwbaird@cascadiaresearch.org or brad.hanson@noaa.gov

Robin Baird, Cascadia Research
Brad Hanson, Northwest Fisheries Science Center, NOAA Fisheries