This section is from the book "Frank Forrester's Fishermens' Guide", by Frank Forrester.
The Cunner, or nipper (so called from their nipping bite) is a sea fish found all along the Atlantic coast, from Delaware Bay to Newfoundland. They are caught most plentifully near rocky shores, and are supposed to feed chiefly on Crustacea. They are very annoying to the fisher for tautog or rock cod, as they swarm plentifully and take off with great readiness the bait intended for larger prey. They make, however, an excellent and favorite pan fish, and there are two or three old fishermen at Swampscott who devote themselves entirely to catching cunners in the cunner season, that is, from the middle of June to the middle of September, and selling them in the Boston market. They are from five inches to two feet in length, and in color no two are exactly alike. The general color is black mixed with brown, with faint transverse bars of an uncertain dusky hue. Large ones sometimes show a light orange tint throughout the whole body, with the head and gill-cover of a chocolate color mixed with light blue, and with blue fins. I have seen specimens thirteen inches in length, weighing a pound, so black as to be hardly distinguishable at the first glance from the tautog or black-fish, while others, equally large, were throughout of a vivid light yellow, varied with spots and bars of shades of the same color. They are fished for with the usual black-fish tackle, and clam bait. In fact they will bite at any bait used in fishing sea fish.