All appearances to the contrary, it's not a rocket launcher! Rather it's a Pop-up Satellite reporting Archival Tag (PSAT). These tags stay on a study animal for months or even years, observing. At a programmed time, the tag separates from the animal and floats to the surface to satellite report what has been observed.

PSAT tags have been used for decades to study highly migratory species such as tuna and shark in particular. By observing and timing light (day/night) and sea surface temperature observations, the animals migratory path can roughly reconstructed.

That works well at oceanic scales, but a lobster slowly shuffling across the seafloor is a different story. Students Bryan Morse and now Emily Blacklock at the University of New Brunswick found a way, though. The 'magic' comes down to two things. First, the tag observes depth and temperature with very high precision, such as just centimeters for depth. These timed observations are compared to tidal and temperature models of the Bay of Fundy where the lobsters are tagged, establishing a detailed migratory path, a detailed record of periods or rest and migration etc.

But, reconstructing such a path takes a lot of data.and PSAT are normally limited by their available battery power. This is where the tags wrap-around solar panel comes in. You can see it in the pictures as the black squares with silver boundaries. Once popping up, the tag bathes in the generous Canadian sun, floating with the currents and reporting. Not each tags data set will be big, as some might quickly was ashore or get caught in marine debris or get sampled or eaten by a curious predator. But many continue reporting for months, some for over a year. And thus provide a treasure trove of data.

You can see that in the graph, which provides the daily total satellite messages received from a set of 63 tags. In the spring of 2024 as sunlight became more available again, we see some holdover tags from the previous years tagging campaign still reporting (blue area). Then in April 2024 many more lobsters were tagged. Both tag testing and early shedding of some tags resulted in reporting into the early summer (orange area). Then in August came the programmed pop-up time and we see a huge spike of reporting. The satellite airwaves were busy now with reports coming in from many tags that had popped up from their lobsters (green area). Data packets with treasured insights literally arriving by the hundreds and thousands per day. Towards fall, reporting declined with the shorter days and more tags meeting their fate.... although some may later be tracked to some shore or picked up by a beach commercial to reveal their full dataset stored in their gigabyte memory.

This tagging story is another great example of how marine science and technology interplay. Once limited to a few species, tags became more capable. Better and more sensors. More memory. Solar power even! These improvements can now give researchers a higher resolution picture of the migration and behaviour of more animals. Which will surely need to new questions. Which yet another generation of tags and tools may ultimately answer.