The Fishing Industry

by William E. Gibbs

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.

The fisherman’s harvest differs from that of the farmer in one important respect. Fishes grow for three or four, or more, years before they are mature. Now, only mature fish as a rule have any considerable commercial value, and only mature fish are able to reproduce their kind and so maintain the existence of the fishery. On the fishing grounds, both mature and immature fish are mingled together, and in capturing the one it is practically impossible to avoid netting the other. To some extent the capture of immature fish is avoided by making the mesh of the net of such a size that the smaller fish can escape. With drift nets only mature fish are caught, the small ones escaping; but with trawl nets it is otherwise. The trawl net is essentially a large string bag that is drawn open-mouthed along the sea bottom, scooping up wholesale all bottom-living fish, such as cod, haddock, sole and plaice. All go into the net, both large and small, and, although the young fish ultimately escape through the meshes, many of them are damaged in so doing, while many young, flat fish, lying on the sea bottom, are damaged by the foot rope of the net, as it passes over them. Certain fishing grounds, such as the Dogger Bank, were almost depopulated of flat fish in the years just previous to the war.

Fortunately for the future of the fisheries, the trawl, can only be worked on smooth ground, and at depths not exceeding two hundred and fifty fathoms, so that only a small percentage of the actual fishing grounds is affected by it. Also, when a fishing ground shows signs of becoming exhausted by over-fishing, it is less frequented by fishermen, owing to the reduced catches that can be obtained, and thus it tends automatically to recover. Nevertheless, it is desirable that fishing should be so organized and restrained, that the fertility of the fishing grounds is not imperilled. In the distant future it may become possible to re-stock partially exhausted grounds with young fish, artificially reared in a hatchery.

Oceanography—the study of the ocean and its inhabitants—is one of the youngest of sciences. Yet, to an island people such as we are, it should be one of the most important, for it is only by the study of oceanography that we can hope to found a systematic, organized aquiculture.

The beginning of a simple aquiculture is to be seen in the cultivation of shellfish, such as oysters and mussels, by the inshore fishermen.

Of recent years, experiments have been carried out by the Fishery Boards of England, Scotland, Germany, and the United States of America, with the object of increasing the productivity of certain fishing grounds by adding large numbers of artificially hatched, young fish. For some years the Fishery Board for Scotland added annually about twenty million plaice larvae to certain confined sea areas (Upper Loch Fyne), and found, as a result, that the number of young plaice on the shallow beaches was doubled.

In some cases a new species of fish has been introduced into a particular fishing ground, with marked success. Thus the U.S.A. fisheries collected and hatched the eggs of the shad on the Atlantic coast and introduced the larvae into the Pacific, with the result that a profitable shad fishery has now been established on the Californian coast.

The application of science to the fishing industry is not restricted to biological investigations of the food, habits and development of living fishes. It is developing new processes for the better preservation of edible fish for food purposes, so that the large quantities of fish caught periodically—for example, in the summer herring fishery—may be stored up for gradual consumption during the winter. It has shown that fish waste can be manufactured into glue, cattle food, and fertilizers. It has developed into a profitable industry the extraction of oils from both edible and inedible fish, and the conversion of these oils into hard fats, suitable for the manufacture of soap and margarine. It has demonstrated that the skins of certain fish, notably the shark, can be tanned to make excellent leather.