Interesting dogwhelk behavior in lab

The other day I was working with dogwhelks in the lab and I noticed one of them was stuck hanging from the top of the cage by a byssal thread. Apparently, a mussel had attached a thread to it and when I turned the cage on its side, the dogwhelk was dangling by it. The poor thing was clearly trying to grab something to get unstuck, but there wasn't much for it to hold onto. I wanted to see if it could get itself out of its unfortunate situation, so I set up my GoPro and started filming!

I soon noticed another dogwhelk crawling up the side of the tank and heading directly toward the top where the dangling dogwhelk was attached. It then proceeded to push on the threads, causing the dangling whelk to bounce! Was this dogwhelk trying to free the dangling one? Here is the 8x speed footage!

I waited a long time for the scene to progress, but the helper dogwhelk didn't break the byssal thread and eventually crawled away. The dangling one wasn't able to grab anything on its own, so I pushed it over to the side of the tank where it held onto the wall, started crawling, and eventually broke the thread and freed itself. 

My first time recording drilling?

In my continued effort to record dogwhelk rasping, I think I finally got a dogwhelk to drill a mussel glued to my hydrophone! Previously, the dogwhelks drilled all the other mussels in the tank, but not the only mussel that we wanted them to drill.

We've captured this process using time-lapse photography, and here are a couple pictures: one with the lights on during the daytime and one with them off and a red light on at night.

Here's what you're seeing: The cord is connected to the hydrophone, which is a black puck-like object. The hydrophone is on top of a black mussel, and the dogwhelk is the grey-white thing on the mussel. This is easier to see in the not-red photo. There is also a smaller mussel just to the right of the larger mussel with the dogwhelk on it. The smaller mussel is only there because it was attached to the large one and I didn't want to disturb it by pulling it apart.  Finally, there is a thermometer in there with them, and the tank itself is in a cooler.

We have yet to go through the audio files to see what we can hear, but at least this time we know the snail was drilling in a quiet room, so the odds are in our favor to hear some rasps!