discussion / Biologging  / 10 April 2024

Fully-retrievable Satellite Tags for Seals?

Hello WILDLABS biologgers! 

I am wondering if anyone knows of any satellite telemetry devices for use in the marine realm (specifically for pinnipeds - seals/sea lions) that function similar to a 'backpack' style tag (i.e. glued to fur, such as a SPLASH or SPOT tag) which are fully retrievable? More specifically, I am wondering if there is either a new or existing fit-for-purpose type tag that minimizes drag during attachment (as a typical backpack tag would) while still being retrievable after deployment (positively buoyant or a low-profile pop-off style deployment), and/or other solutions others have used to successfully relocate tags.

Typically, pinniped tags tend to be shed and fall straight to the bottom of the sea/river area and are often not found again. I am working with some stakeholders who have concerns of leaving any tags in the environment.  While I realize most tags are encased in epoxy and therefore shouldn't 'leak' into the environment, there is a desire to have a satellite telemetry program that essentially results in a 'leave no trace' approach for tagging equipment deployed on individuals. Ideally, we would like this tag to provide location and dive data at fairly high resolution (e.g. several successful uplinks per day). We are also very unlikely to recapture these individuals while the tag is attached and would need to have satellite uplink capabilities.

If there are no tags like this, would this be of interest for development?



Alas I have no recommendations for you, but I want to say kudos for pursuing a no-trace approach.  Granted the impact of a handful of tracking tags being discarded is way down the list of global pollution sources by impact, but it's good (in our field) to lead by example.

Hi Courtney,

One challenge for auto-detaching tags on seals is kind of logistical/financial rather than technical.  A floating tag requires a vessel to go retrieve it, and since seals may venture pretty far out to sea, it might require a pretty substantial vessel. Many seal projects I've worked with don't even have boats as a regular part of their work, so this could require a significant increase in operational costs and/or efforts. Not impossible of course, just a consideration. 

Wildlife Computers has a remote-controlled release mount for seals, which would allow you to wait until they're on shore to drop it off, obviating the need for a boat.  This still does leave some material behind. Making a predictable/controllable release mechanism that wouldn't leave something behind is quite a challenge for seals, where epoxy to the fur seems to be the most reliable attachment method.

Thomas Gray
Woods Hole Group
Argos satellite system manager for North America
WILDLABS Research Participant
Commenter level 2
Conversation starter level 1

Hello @CourtneyShuert 

If I am not mistaken, Wildlife Computers was developing or has developed a remote release package for such an application as has a much smaller company, Desert Star Systems. I do not know where either company stands in terms of functionality, but I think for both cases the animal still has to carry some kind of an attachment plate that will eventually be shed off. In theory (purely theory) and assuming a product exists, you/they could consider adapting the material of the plate to something that is 'sustainable' and not plastic or similar.


(edit: I noticed Kyler linked the WC product above)

Hi Courtney,

I haven't read through all the Wildlife computer options but I have heard of people using Zinc Anode disks as a type of slowly degrading attachment point for tags. We use these also as a backup for other types of releases on Oceanographic moorings etc. It would take some testing to see how the zinc could be attached or be small enough to degrade completely away from the pinniped but still be strong enough to hold a tag.....just some thoughts!