Common bleak extracted from the scales of the common bleak, so-called "Essence Orientale" or "pearl essence", (used in making artificial pearls) which is crystalline guanine. Common bleak The common bleak ("Alburnus alburnus") is a small freshwater coarse fish of the cyprinid family. The body of the bleak is elongated and flat. The head is pointed and the relatively small mouth is turned upwards. The anal fin is long and has 18 to 23 fin rays. The lateral line is complete. The bleak has a shiny silvery colour; and the fins are pointed and colourless. The maximum length is approximately 25 cm. In
Crab meat and the animal is then returned to the water. The practice is defended because some crabs can naturally autotomise (shed) limbs and then about a year later after a series of moults, regenerate these limbs. In Western Europe crab meat is derived primarily from the species "Cancer pagurus". "C. pagurus" is a large crab noted for the sweet, delicate flavour of its meat. It is also known as the "Brown Crab", the "Common Crab" or the "Edible Crab". The United Kingdom is the largest fishery for "C. pagurus" with large fisheries in Scotland and a smaller but substantial fishery in