This image was taken at ~2m depth, with a small ROV in Halifax, NS in May. We're in the Northwest Atlantic Ocean and as far as I know, don't have gooseneck barnacles.
Considering that it may be a polychaete worm as several other species were sighted during same dive (Tomopteris ?, Chaetopterus) and the fan appears to have more than 10 appendages. Possibly a sabellid or goblin worm?
Sizing is difficult to estimate but ~5cm in length.