In its essential features the story of the gradual rise and development of the fishing industry closely resembles that of its sister industry, agriculture. In both cases man became skilled in harvesting long before he understood anything of the art of cultivation. Primitive man roamed from place to place in the wake of the annual wave of harvest, gathering wild crops of grain, berries and fruits. Ultimately he became alive to the significance of seed, and the nomad settled down to raise crops year after year in the same place. Gradually he acquired a knowledge of the conditions of temperature, moisture, and quality of soil that favoured the growth of his plants. Finally, he discovered the principle of the rotation of crops, and, by this, not only increased the productivity of his land but also laid the foundations of a systematic agriculture. Of recent years agriculture has been rapidly developing into a science. Chemistry, physics, botany, plant physiology, and bacteriology, all contribute increasingly to a full understanding of the inner processes of the growing plant, and indicate more and more clearly the exact relations that exist between the conditions of growth and the character and amount of the resulting product. The art of fishing is one of the oldest in the world, yet even to this day the fisherman is simply a hunter, gathering where he has not sown, and differing little, save in mechanical efficiency, from his primitive ancestor fishing with spear and trap. Only in recent years has any systematic attempt been made to understand something of the forces that produce the annual harvest of the sea. We know very little about the habits of the various fishes that constitute this harvest—their food, their migrations, their reproductive processes, and, in general, the conditions upon which their healthy life and development depend. We have developed highly efficient fishing implements, but we have yet to learn to use them wisely and not too well; to increase the fertility of the various fishing grounds rather than depopulate them by over-fishing and the destruction of immature fish.