Project Title: Monitoring medium and large-scale movements of baleen whales using satellite telemetry
Chief Investigator: Dr Nick Gales
This project is part of a long-term research program to develop a safe and reliable method to track the movements of large baleen whales with radio satellite tags. While the satellite tracking technology is well established, methods to attach the tags to whales that have no significant impact on animal welfare, but provide sufficient attachment time have proven difficult. During this project, which focused on humpback whales and blue whales, substantial problems with electronic failure and short attachment times were experienced. These failures resulted in very little whale movement data being acquired. Subsequent assessment of points of failure and the ensuing design changes have now resulted in a tag that works predictably for several weeks post deployment. Further improvements in tag design and function are expected in future deployments.
This project has achieved the objective of further refinement of tag design, but within the timeframe of the project itself the results have been frustrating and disappointing. Two problems confounded our efforts; issues of early tag expulsion due to sub-optimal design and multi-factorial electronic failure issues. Whenever a tag ceases to transmit post-deployment it is generally not possible to disentangle these two points of failure.
The deployment of safe and reliable tags on whales is still developmental, and an approach that minimises the length of the tag (as our approach does) leads to the greatest risk of early tag failure. While the tag failures in this project have meant that only limited data on whale movement has been acquired, the work undertaken in this project has enabled us to solve the electronic failure issue and to extend the tag life on the whale this has been demonstrated by the most recent tag deployment. The electronic failure issue was resolved through substantial redesign of the electronics and by switching suppliers (we changed from Sirtrack Ltd, New Zealand to Wildlife Computers, USA). Our subsequent success in increasing tag attachment duration to close to 4 weeks has been achieved by further improvements in design and through increases in tag length.
In summary, while the data outcomes of this project are disappointing the troubleshooting and design actions have resulted in substantial improvements in tag design to the point where we now have a tag that transmits predictably after deployment and can acquire location data for several weeks. Further improvements in tag longevity are anticipated in future deployments.