Here's a link to "Fishes of the Gulf of Maine", which I believe was taken from an old book, great source for identifying fish, and although the drawings are not in color the descriptions are excellent.
They are great tuna bait for sure. A lot of times when the draggers pull back you can get some floaters for your bait if you want to use whiting for tuna. DEADLY! Also a sabiki rig tipped with a little clam will produce whiting quickly for you.