Greenling have to be at least 12" to keep and therefore at least that size to enter AOTY. A 12" greenling at 12 points per inch is worth 144 points which seems too much for a small bony fish that I think most of us wouldn't be too interested in otherwise...And that's just the minimum size. At 12 points per inch, a relatively small incidental catch of limited sport or culinary value (IMO) becomes a very valuable fish.
Matt