Two friendly queens of Moellerius heyeri caring for a single incipient fungus garden, which is adhering to the glass wall of the artificial nest X5. (Photograph by Dr. Carlos Bruch.)

Crematogasters that live in the moist cavities of plants (Plectronia, Cuviera) the refuse heaps consist very largely of such ejected pellets and produce a luxuriant growth of aërial hyphæ which are cropped by the ants. From such a condition it is, perhaps, only a short step to the establishment of small gardens consisting at first of the pellets and later of these and accumulations of extraneous materials, such as the feces of the ants, those of caterpillars and beetles, vegetable detritus, etc., which might serve to enlarge the substratum. and increase the growth of the fungus. The selection of particular species of fungi and their careful culture and transmission are evidently specializations that must have been established before the stages represented by even the most primitive existing Attiini could have been attained.

Whatever may have been the processes whereby the ancestral Attiini developed the fungus-growing habit, it must have originated in the more humid portions of the tropics, since nearly all the more primitive species of the tribe are still confined to the rain-forests. But certain species soon found that by sinking their galleries and chambers to a greater depth in the soil they could easily carry on their fungus farming even in arid regions. Thus some species of Moellerius. Trachymyrmex and Cyphomyrmex have come to live. in the dry deserts of Arizona, New Mexico and northern Mexico, and as they can always find in such localities enough vegetable material for the substrata of their gardens, they have attained to a control of their environment and food-supply, which even the human inhabitants of those regions might envy.

THE MARINE FISHERIES, THE STATE AND

MAN

THE BIOLOGIST

By WILL F. THOMPSON

ANY of the great marine fisheries of the world lie within the jurisdiction of more than a single sovereign country. The great North Sea fisheries, those of the Grand Banks, the salmon fisheries of the Fraser River (now nearly extinct), and the halibut fisheries of the North Pacific might be cited as examples. It would seem that this divided ownership has reacted most disastrously upon their care. Responsibility seems in such cases to be simply lost, not divided, and the net effect is that no one cares to sacrifice his own interests to maintain the fishery for the benefit of all. The splendid scientific work done in the North Sea contrasts vividly with the relative futility of the movement to conserve the vanishing bottom fisheries there by regulatory laws. There is simply no machinery capable of overriding the selfish interests of the few in each country, supplemented as it always is by the general suspicion one nation seems to think it necessary to have of every other nation.

The case seems far more hopeful, where there is no division of authority. And in many of our great states fisheries exist which are entirely under the legal control of a single state government.

That is true in California, where there is not a single fishery common to both its own water and the waters of another state or country save of the sparsely inhabited desert of Lower California, to whose less exploited fisheries vessels often go from Southern California ports. There is thus no possibility of shirking responsibility the care of its fisheries devolves upon California alone by virtue of the Constitution of the United States and of its geographical position. No question of nationalism can be involved, only that of sectionalism. As a result, the failure to conserve the fisheries for the people of the entire state can result only from faulty organization of public opinion and the lack of real proof of the necessity of conservation.

The securing of this proof of the condition of the fisheries has in California, as everywhere else, been recognized as a legitimate function of the responsible government, and the proper execution of that function is vital to the success of any popular movement toward conservation. Unlike the forests and the mines, private ownership has never been granted in the fisheries, save in the case

of oysters and those of certain fresh waters, and for that reason aroused popular opinion is entirely likely to control in the end. But powerful interests have grown up who will vigorously object to curtailment of their activities. Something tantamount to legal proof is necessary before what seems to them confiscation may be indulged in. And they have in the past shown a vitality which augurs ill for any but well-based movements toward conservation. The general policy of conservation is, moreover, largely supported by men among the public who are not trained scientists and do not know the value of evidence. Their conclusions as to the existence of depletion may carry weight where, as in the case of birds and mammals, any honest man may observe conditions with his own eyes, and where powerful interests are not placed in jeopardy. But in the marine fisheries this is not true, for the fish are not easily observed and the evidence must come from statistical proof of comprehensive character. Under such circumstances the cry of conservation, raised hysterically and hastily, as is done even by scientists at times, must in the long run lead to failure and the injury of the cause at stake. And measures of regulation or restriction passed in response to pleas made on an insecure basis must in the end fail to justify themselves. So the acquirement of real knowledge, while a protection to the men legitimately engaged in exploitation, is equally such to the cause of conservation itself, for it should not only prevent this lack of balance and undue regulation, but it should prevent the growth of interests which must later be curtailed.

This necessity of knowledge was acknowledged by the fishery authorities of the State of California when they instituted the present system of observing the fisheries. Their action in this regard was based on the following facts: First, that enough accurate knowledge already exists to prove the susceptibility of marine fisheries in general to overfishing; second, that proof is required. in the case of each individual fishery, and that there is no way of knowing the strain a species will stand save by submitting it to one; third, that such a course of action implies the duty of the state to maintain a constant and intelligent ward over its fisheries; and finally, that such a ward is possible and that it implies continuous and prolonged statistical and biological investigations.

In regard to the first point, the existence of proof that marine fisheries are exhaustible, we must turn to the oldest and best known of fisheries, namely those in North European seas. Contrary to the opinions of many, these great fisheries cannot justifiably be called ancient. The use of steam vessels began in 1880; the otter trawl first came into use in 1895, laying open to exploitation the depths of the ocean below fifty fathoms; while the means of mar

keting and the extent of the demand increased equally with the recent great industrial expansion. The latter involved the development of railroads, the refrigeration of food products, the use of cans for their preservation, fast steamships to carry them, the growth of city life as a market, etc. Meanwhile, as cited by Jenkins ("The Sea Fisheries," 1920) as an illustration of the trend of the times, the number of fishing vessels in the port of Aberdeen, Scotland, increased 258 per cent. in the period 1897-1903, and according to the estimate of the same authority, agreeing with that of others, the efficiency of each steam trawler of to-day exceeds eight times that of the sailing trawler it displaced (aside from the independence the steamer has of weather and distance). The fisheries in other parts of the world are still more recent, and show the same great increase in apparatus although not necessarily in catch. If these facts are considered, it is impossible to doubt that, unless civilization comes to an abrupt pause, with the destruction of our highly developed transportation and of our industrialism which builds towns and markets, we are on the brink of an era of exploitation of our fisheries, and not at the crest of such an era. And the existence of overfishing now becomes a serious problem, for if the fisheries do show depletion, it is indeed a serious question whether they will, even in their more stable parts, survive the coming strain. Faith in our destiny and that of the world implies care of our resources of fish.

That they do show depletion in certain fisheries is now proved. The most clearly ascertained instances at present are those of the bottom fisheries. Thus the halibut in both the Atlantic and the Pacific has decreased with great rapidity. But the bottom fisheries of the North Sea for plaice and other allied species are, as Garstang (The Impoverishment of the Sea," 1900) says, "not only exhaustible, but in rapid and continuous process of exhaustion." This conclusion has been seconded and supported by men who have, in the various countries around the North Sea, actually had the examination of the statistics in their care, as Heincke, Fulton, Thompson and others, such as Jenkins and Allen. And if these bottom fisheries already show exhaustion, since they are more stationary, are most highly valued, and were first sought for, it is not to be expected that "pelagic" fish will show otherwise upon the imposition of greater strain, even though they are more abundant. But in this connection, it must, indeed, be remembered that there is no accurate means of determining whether pelagic fish actually are more abundant than other fish in the ocean-al though we do know that the cod and the herring, for instance, are not numberless, as some estimates have made them.

Against such a view there has been urged the objection that

the fisheries seem to be prospering and to be continuing on a firm basis. That fact may be granted, however, without conflicting with the above conclusions. It may be admitted that the total yield of the fisheries does not everywhere seem to decline, but it can be proved that continuously greater toil is required to obtain it. That this decreasing yield for the effort involved does not attract more attention should be understandable when it is considered that the cost of catching fish is but a fraction of the cost of distribution. Thus the fisherman may receive eight cents per pound where the retailer asks forty cents, and doubling the fisherman's price would add but a fifth to the retailer's price. The cost of obtaining the fish could be multiplied many fold without seriously affecting the final price to the consumer. The latter is, moreover, willing to pay high prices for a product to which he has become accustomed, and the rarer it is the more he will pay. The increase in initial cost does not seem, in fact, to be of the greatest importance.

There is also this fact to be taken into consideration, that there are influences which actually counteract the effect of increasing scarcity in raising the initial cost. The accompaniments of that intensified exploitation which results in depletion are the constant broadening of the fishing grounds, the inclusion of more than one species of fish and of inferior quality in the catch of the boats, the development of means of preservation, the constant improvement of gear and the increase in quantity of apparatus. All these things tend to eliminate the great and sudden fluctuations in amount of yield which are characteristic of fisheries confined to one species or one locality. These variations in yield render the exploitation of the fisheries expensive and uncertain because the periods of abundance must be made to pay interest upon the capital and to maintain the organization during periods of scarcity. Their elimination as a result of intense fishing undoubtedly does reduce the cost of fish to the consumer, perhaps to the extent that for a while the influence of depletion in raising the initial cost will not be felt.

But in the end that very fact may defeat the natural safeguard which should protect a species, namely, the lack of profit in carrying on a fishery when it comes dangerously near to exhaustion. It becomes possible to prolong a fishery because other species are taken; the by-product becomes the mainstay of the business and the depleted species is kept under a strain for which it could not itself pay. If it were not for cod, perhaps the halibut fishery of Iceland might have long since collapsed; and if it were not for the cheaper round fishes, the flat fishes in the North Sea might be pursued far less rigorously. On the Pacific coast, the tuna and sardine

Vol. XV.-35.