Loggerhead turtle equipped with a satellite tag. Source: Miquel Gomila/SOCIB
06.07.2020 Animal tracking applications

Data collected from animals can help ocean observing systems

Data collected on animals by Argos satellite telemetry can be provided to physical oceanography, to fill in a number of gaps in the ocean observing systems. A study details how animal-born instrumentation can complement the Argo automated profiling float array.

Photo: Loggerhead turtle equipped with a satellite tag. Source: Miquel Gomila/SOCIB

Instrumenting animals with satellite telemetry transmitters is primarily done to gain knowledge on their ecology, assess species vulnerability to environmental changes and/or species distributions, collecting location data but also for some tags temperature, conductivity, salinity, oxygen or chlorophyll. We’ve shown here several studies where the data collected by Argos tags on animals were also used by physical oceanography models and research (elephant seals, olive Ridley turtles, bowhead whales…). But is there a real specific interest in such uses, e.g. in complementing other systems?

3000 telemetry tracks to identify areas where animals could complement automated floats

A study considered this in comparison with one of the largest automated physical data collection system – the Argo profiling float array. Using a database of more than 3000 telemetry tracks from animals, representing 183 species from eight major groups (tuna and billfishes, sharks and rays, marine turtles, pinnipeds, cetaceans, sirenians, flying seabirds and penguins), this analyses identify potential areas where Animal-Born Instrumentation could complement Ocean Observing Systems.

Maps of the spatial overlap between gaps of the Argo network and extent of occurrence, by group of animals. In red, the animal borne instruments complement the best the Argo Array. In blue, there is no complementarity, often simply because the species does not live in the area (source: [March et al. 2019])
Maps of the spatial overlap between gaps of the Argo network and extent of occurrence, by group of animals. In red, the animal borne instruments complement the best the Argo Array. In blue, there is no complementarity, often simply because the species does not live in the area (source: [March et al. 2019])

The interest of data collected by animals depends of course of each species’ behaviour, and of the areas where they are living. However, since large areas of the ocean are under-sampled by the Argo array, due to environmental (e.g. sea ice, shallow water), logistical (e.g. remoteness), political (e.g. Exclusive Economic Zones) and security (e.g. piracy) reasons, a large quantity of those animal-born data are interesting to fill in gaps. Moreover, the marine animals which need to breath dive and surface every so often: they thus can record at high frequency (e.g.) temperature vs depth profiles.

Species of particular interest

Geographically, the animals living at latitudes closer to the pole than 60°, or on the continental shelves are filling some of the main gaps of the Argo array. Pinnipeds are thus of particular interest since they can live at the higher latitudes. Some animals are also either living close to the surface or diving very deep (down to 4000 m for some whales), both being under-sampled ocean layers. Sea turtles thus can complement the coverage over shallow waters and surface layers, since they are often found in shallow tropical or temperate waters, close to the surface.

The main areas where animal-borne instruments can contribute are marginal seas and shelf regions upwelling areas, but also the upper 10 m and deep ocean, and poleward of 60° latitude. (source: [March et al. 2019])
The main areas where animal-borne instruments can contribute are marginal seas and shelf regions upwelling areas, but also the upper 10 m and deep ocean, and poleward of 60° latitude. (source: [March et al. 2019])

 

Ensuring sustainable observations

This study shows that the ocean observing system in all those regions of the ocean would greatly benefit from using animal-borne instrumentation data in addition to the automated instruments currently used. The animal-borne programs should have clear biological oriented objectives and consider welfare and ethical issues, but combining biological and physical studies can better ensure sustainable observations for both fields.

 

Reference

  • March D, Boehme L, Tintoré J, Vélez-Belchi PJ, Godley BJ. Towards the integration of animal-borne instruments into global ocean observing systems. Glob Change Biol. 2019;00:1–11. https://doi.org/10.1111/gcb.14902