(2) The various species of fish that inhabit the surface waters of the sea are called “pelagic.” They include the herring, mackerel, tunny, flying fish, sword fish, and many sharks, also various marine mammals, such as whales, grampuses, porpoises, dolphins. Amongst pelagic fish are included some of the smallest (plankton) as well as some of the largest (whales) of all living creatures. Pelagic fish pass their whole life swimming at or near the surface. They enter the shallow water offshore only for prey or, in some cases, periodically to spawn. The majority spawn in the open sea, far from land. Unlike demersal fishes, the distribution of the different species of pelagic fishes depends very much upon local conditions of light, water temperature, and the character and quantity of food available. They do not hunt their food individually to the same extent as demersal fishes, but generally filter it from the water as it passes through their gill-openings. Although not so widely dispersed as demersal fish, they are, in favourable circumstances, dispersed over large areas by swimming and by ocean currents. All pelagic fish are “round.” With the exception of the mackerel, the important edible pelagic fishes belong to the herring family, and are known as the Clupeidae. They include— Herring—found from the White Sea to the Bay of Biscay. It is the most abundant of all food fishes. Sprat—found from the North of Europe to the Mediterranean. Pilchard—ranges from the English Channel to Madeira and the Mediterranean. Skipper “sardines” are young herring, pilchard, and brisling. There is also— Mackerel—found from the North Sea to Madeira and the Mediterranean. (3) The shallow-water of the seashore is inhabited by certain animals (shellfish) not found elsewhere, including various mollusca, e.g. mussel, cockle, oyster and periwinkle, and crustacea, e.g. lobster, crab, prawn, shrimp. In addition to these, there are various species of immature offshore fish, e.g. plaice and dabs. The inhabitants of this shallow, coastal water are called “littoral” fish. The distribution of such littoral fish depends not only upon the water temperature and the amount of light, but also upon the character of the shore—whether it is rocky, or soft and sandy—and more especially upon the animal and vegetable products of the adjacent land, e.g. plants, seaweed, worms. Littoral fish do not swim very far, but become scattered inadvertently over considerable distances by currents and other mechanical means. [Illustration: FIG. 5 HERRING (_Clupea harengus_) Length slightly above 12 ins. _Food._—Plankton (_copepoda_). _Range._—From the White Sea to the Bay of Biscay.]