u/InappropriateUnicorn

I'm working on this whale mobile from Wool Couture and I'm a little confused on how to join these 2 fins together.

I would normally fasten off the 1st fin and then have joined the 2nd fin as usual, but how do I join them when there's still a live stitch on the 1st fin?

My inclination is to put the hook through the live stitches on both fins and then DC into the next stitch on the 1st fin. Would this be correct? Should I include the broken off yarn strand?

To note: I've got to the first comma of round 6, and the pattern uses UK terminology.