The study of the ecology and behaviour of marine animals can be a difficult task, especially the study of pelagic species. In order to successfully study these creatures an alternate method of analysis must be employed; this method is known as biologging. Biologging is the use of a miniaturized animal attachment tag for logging or relaying data from a free ranging animal1. Whilst the marine environment causes a number of difficulties, biologging still has had a rich history of use in the study of marine species1,2. In a presentation by phD student Stephanie Brodie of UNSW at the Sydney Institute of Marine Science, she outlines a number of uses of biologging; including examples from her own research.
The first recorded use of a biologger in the marine realm was in 1964 when Kooyman, attached a biologger to a Weddell Seal in the Antarctic to measure dive capacity1. Since then a biologgers have greatly increased in complexity and decreased in size1,2. Biologgers can be used to detect a number of measurements including depth, temperature, salinity, acceleration and heart rate2.
Brodie explains that today there are four main types of tagging options; Archival: these biologgers store vast amounts of data on board, but require retrieval from the animal1. Another option is satellite tracking; this is used for long term deployments, relaying movements in real time, but require the animal to break the water’s surface in the presence of an overhead satellite1. The last is a Pop-up Satellite Archival Tag (PSAT) and combines both the archival and satellite tags in one; making it both effective, but expensive1. Acoustic telemetry is yet another method of leading the movements of aquatic animals; these biologgers are cheap, long lastly and are often surgically inserted into the animal1,2,4. This method requires an acoustic receiver to record and time stamp the data4.
Cuttlefish Breeding and Acoustic Telemetry
The Giant Australian Cuttlefish, Sepia apama has been of interest for a number of years with population numbers declining rapidly. Acoustic telemetry and accelerometers were used in a study by Payne et al (2010) to determine breeding duration of sexes and to estimate energy expenditure3. Using acoustic telemetry, they found that males were present at breeding grounds for a significantly longer duration than females, in order to mitigate the effects of sexual competition3. Whilst using accelerometers and known biological requirements, metabolic rate can be deduced for the Giant Cuttlefish during breeding season3.
Lifestyles of Yellow-tail Kingfish
Yellow-tail Kingfish are a pelagic fish of considerable recreational and commercial importance in Australia. Stephanie Brodie’s own research project centers on the Kingfish; Kingfish captured, are tagged with accelerometers and swum through a swim tunnel at controlled speeds (Figure 1). Kingfish acceleration and oxygen consumption is then measured, and from this data Brodie has found that increases in swim speed are correlated to increased metabolic rate4. Brodie has then released these animals back into the water; tracking diurnal movements, migrations and metabolic rate. Thus far her results have indicated that a Kingfish need to consume 3% of its body weight in teleost prey per day to cover their complete energy expenditure (movement, growth and reproduction)4.
Figure 1 Stephanie Brodie preforms surgery on a Kingfish, inserting a Biologger: taken by Al McGlashan6.
Marine Mammals as Oceanographers
One of the more unique applications of Biologgers has come from a study in Antarctica, where recent data has shown a new source of Antarctic bottom water. Antarctic bottom water is the cold dense water found at great ocean depths; it is also a vital component in global ocean circulation5. Previously three regions around Antarctica have been described as sources for Antarctic Bottom Water; but using biologgers attached to elephant seals (Mirounga leonine),a fourth location of Antarctic Bottom Water formation has been discovered5. Elephant seals frequently dive to great depths; up to 1800m in some foraging events. Using conductivity-temperature-depth (CTD) sensors, seals were able to map the extent of the Antarctic Bottom Water formation at Cape Darnley5.
Undoubtedly, Biologgers are a fantastic tool for biologists and have applications on the land, sea and in the air. They have enabled us to determine population dynamics, behavioral ecology, assisted in conservation efforts, as well as recent oceanographic applications. Below are a number of references and readings on the history and uses of biologgers in biology.
- Roper-Coudert, Y., Beaulieu, M., Hanuise, N. & Kato, A. 2009. Diving into the world of biologging. Endangered Species Research, 10: 21-27.
- Rutz, C. & Hays, G.C. 2009. New Frontiers in biologging science. Biology letters, 5(3): 289-292.
- Payne, NL; Semmens, JM and Gillanders, BM. Examination of Giant Australian Cuttlefish ‘Sepia Apama’ Breeding Behaviour through Acoustic Telemetry [online]. South Australian Naturalist, The, Vol. 84: 1, 2010: 38-41.
- Brodie, S. 2014. Unpublished data.
- Ohshima, K. I., Fukamachi, Y., Williams, G. D., Nihashi, S., Roquet, F., Kitade, Y., Tamura, T., Hirano, D., Herraaiz-Borreguero, L., Field, I., Hindell, M., Aoki, S. & Wakatsuchi, M. (2013). Antarctic Bottom Water production by intense sea-ice formation in the Cape Darnley polynya. Nature Geoscience, 6(3): 235-240.