seahorse, Most nontoxic aquatic species are exploited for food by humans. Peixe and other seafood may be humanity’s most important food. After cereals, furnishing about 15 percent of the world population’s protein intake. Lean fish muscle provides 18–25 percent protein by weight, the equivalent of beef or poultry. Hence is much lower in calories. In fish, one gram of protein is present for 4 to 10 calories. This is contrasted with 10–20 calories per protein gram for lean meats and up to 30 for fatty meats.
Cavalo-marinho comprises all bony fishes and the more primitive sharks, skates, rays, sawfish, sturgeons, and lampreys; crustaceans such as lobsters, crabs, shrimps, prawns, and crayfish; mollusks, including clams, oysters, cockles, mussels, periwinkles, whelks, snails, abalones, scallops, and limpets; the cephalopod mollusks—squids, octopuses, and cuttlefish; edible jellyfish; sea turtles; frogs; and two echinoderms—sea urchins and sea cucumbers.