In August of 2018 a team of researchers from Cascadia Research and Standford University tagged a blue whale with an electrocardiogram (ECG)-depth recorder tag to measure and record heart rates and dive depths. This was to date the first attempt to measure a large whale’s heart rate and the finidings were published on November 25 in the prestigious Proceedings of the National Academy of Sciences. This tag was on and recorded during foraging dives as deep as 184m and as long as 16.5 minutes. Through Cascadia’s long term research on blue whales, this individual was identified through photographs as being CRC ID-2021. 2021 was fist identified in Monterey Bay on 7 September 2003 and has been seen 13 time through 2016. Most of these sightings have been in the Santa Barbara Channel and elsewhere in the S. California Bight. With this sighting information we can clearly state this is a full adult blue whale that is at least 15 years old. One of Cascadia’s collaborators in Mexico reported seeing this whale in 2007 in the Gulf of California and states that is a male. Genetic testing will occur on samples collected during the 2018 encounter will confirm the sex.
We recorded a wide range of heart rates from the tag, reaching only several beats per minute during deep foraging dives (bradycardia) and nearly 40 beats per minute at the sea surface (tachycardia) as the whale recovered from its oxygen debt. The latter likely represents maximal heart rate given the measured duration of the heart beat itself, thereby demonstrating the greatest dynamic range in cardiac activity at this scale.
This research was funded by Office of Naval Research Grant N000141912455 and a Terman Fellowship from Stanford University; and permitted by National Marine Fisheries Service (NMFS) 16111, National Oceanic and Atmospheric Administration Office of National Marine Sanctuaries Multiple Sanctuary Permit (MULTI)-2017-007-009, and Administrative Panel on Laboratory Animal Care (APLAC) 30123. The custom ECG recorder tag was funded by the John B. McKee Fund (2018) at Scripps Institution of Oceanography.