Prepping for Pings and Preggos

As with any good project, success starts with one thing: preparation, preparation, and more preparation. So before we head out to sea, I thought I’d give a quick peek behind the scenes at what goes into getting ready.

This time, we’re gearing up for a project focused on where spiny dogfish are found along Sweden’s west coast, how their numbers and size distribution vary across different areas, and how closely related individuals are to one another—and how all of this connects to their environment. We’ll be combining size structure and genetic analyses to paint a clearer picture of this elusive coastal predator. This effort builds on ongoing work, where we’re tagging and tracking spiny dogfish using acoustic telemetry.

Together, these projects aim to support smarter management and conservation strategies, helping ensure that at least one viable coastal predator continues to thrive in the Kattegat and Skagerrak seas.

A true bluebird day on the Swedish west coast—perfect conditions for fieldwork. Photo © Petter Lundberg

Spring in Sweden has been colder and windier than usual, and it feels like everything in the sea is moving just a little slower. Wind, in particular, is a real challenge for the kind of work we do. Luckily, we managed to catch a few good weather days recently and made the most of them—long hours on the water to maintain our coastal network of acoustic receivers.

It’s not exactly glamorous work. In fact, it’s pretty messy. Maintaining the infrastructure means scrubbing off absurd amounts of sea squirts and blue mussels (especially on the shallower receivers), offloading last year’s detection data, and swapping out old batteries. This year, we also took things a step further by upgrading most of the receivers to an open protocol format. That means they can now detect tags from other manufacturers that use the same transmission standard—a big win for collaborative, large-scale tracking.

Receiver retrieved. Clearly, we’re not the only ones who like using them. Photo © Daniel Palm

The slow spring also gave us the chance to test out our ultrasound machine on a few by-caught individuals. Turns out, learning to handle this equipment is trickier than expected. But after lubing up a couple of dogfish, we got to experiment with scanning and later confirmed some of our more plausible observations through dissection. Super useful—and honestly, I’d highly recommend anyone planning to use ultrasound in the field to do a few dry runs beforehand. Things will get easier once we start scanning live animals, since we’ll be able to pick up heartbeats and fetal movement from the pups.

Next up: it’s time to start ordering sampling materials—and, of course, to start praying to the weather gods for a calmer, less windy autumn.

Tiny pups, first spotted by ultrasound and confirmed through dissection. Photo © Petter Lundberg

A spiny dogfish pup. Photo © Petter Lundberg