Short answers, pulled from the story.
The four species of plaice are the European plaice (Pleuronectes platessa), the American plaice, the Alaska plaice, and the scale-eye plaice. All four belong to the family Pleuronectidae and are right-eyed flatfish.
The word plaice comes from the 14th-century Anglo-French plais. That term derived from the late Latin platessa, meaning flatfish, which in turn came from the Ancient Greek platys, meaning broad.
European plaice have a maximum reported age of 50 years and a maximum recorded length of 100 cm. They live on sandy bottoms of the European shelf at depths of up to 200 metres.
The Northwest Atlantic Fisheries Organization classifies American plaice as overfished with no signs of recovery. American plaice are also listed as endangered in Canada due to overfishing, though the Canadian government maintains the species is abundant.
ICES lists North Sea plaice as outside safe biological limits. The World Wide Fund for Nature reported in 2006 that of the eight plaice stocks recognised by ICES, only one was being harvested sustainably, while three were overexploited and landings for all stocks were at or near historical lows.
In North German and Danish cuisine, plaice is commonly filleted, battered, and pan-fried. It is served on open sandwiches with remoulade sauce and lemon, or as a main dish with french fries and remoulade. It also appears on children's menus in Danish restaurants and is available frozen in supermarkets.