One peculiarity of the abysmal fauna, which, to some extent, is a protection against the cavernous jaws mentioned above, is a certain ‘spininess’ which has developed even amongst genera that are elsewhere smooth. Such specific names as spinosus, spinifer, quadrispinosum, are very common in lists of deep-sea animals, and testify to the wide prevalence of this form of defence. A similar spiny character is, however, found in many polar species, even in those of comparatively shallow water; and it may be that this feature is a product of low temperature and not of low level. The same applies to the large size which certain animals attain in the depths. For instance, in the Arctic and Antarctic Seas the isopodous crustacea, which upon our coasts scarcely surpass an inch in length, grow to nine or ten inches, with bodies as big as moderate-sized lobsters. The gigantic hydroid polyps, e.g., Monocaulus imperator of the Pacific and Indian Oceans, illustrate the same tendency; and so do the enormous single spicules, several feet long and as thick as one’s little finger, of the sponge Monorhaphis. Amongst other floating molluscs at great depths, chiefly pteropods, the Valdivia captured a gigantic Carinaria over two feet in length. Of even greater zoological interest were giant specimens of the Appendicularia, which were taken at between 1,100 and 1,200 fathoms. This creature, named by Chun, Bathochordæus charon, reaches a length of about five inches, and has in its tail a notochord as big as a lamprey’s. All other genera of this group are minute, almost microscopic.
There are two other peculiarities common amongst the deep-sea fauna which are difficult to explain. One is a curious inability to form a skeleton of calcareous matter. The bones of many abysmal fishes are deficient in lime, and are fibrous or cartilaginous in composition. Their scales, too, are thin and membranous, their skin soft and velvety. The shells of deep-sea molluscs are as thin and translucent as tissue-paper; and the same is true of some brachiopods. The test of the echinoderms is often soft, and the armour of the crustacea is merely chitinous, unhardened by deposits of lime. Calcareous sponges are altogether unknown in the depths. This inability to form a hard skeleton—curiously enough this does not apply to corals—is not due to any want of calcareous salts in the bottom waters. It is known that calcium sulphate, from which animals secrete their calcium carbonate, exists in abundance; but those animals which dwell on the calcareous globigerina ooze are as soft and yielding as those which have their home on the siliceous radiolarian deposits. Animals which form a skeleton of silex do not suffer from the same inability; in fact, the deep-sea radiolarians often have remarkably stout skeletons, whilst the wonderful siliceous skeletons of the hexactinellid sponges are amongst the most beautiful objects brought up from the depths.
The second peculiarity, for which there seems no adequate reason, is the reduction and diminution in size of the respiratory organs. Amongst the crustacea, the ascidians, and the fishes this is especially marked. The gill laminæ are reduced in number and in size; and the evidence all points to the view that this simplification is not primitive but acquired, being brought about in some way by the peculiar conditions of life at great depths.
When the first attempts were made to explore the bed of the ocean, it was hoped that the sea would give up many an old-world form; that animals, known to us only as fossils, might be found lurking in the abysmal recesses of the deep; and that many a missing link would be brought to light. This has hardly proved to be the case. In certain groups animals hitherto known only as extinct, such as the stalked crinoids and certain crustacea—e.g., the Eryonidæ—have been shown to be still extant. The remarkable Cephalodiscus and Rhabdopleura, with their remote vertebrate affinities, have been dragged from their dark retreats. Haeckel regards certain of the deep-sea medusæ as archaic, and perhaps the same is true of the ascidians and holothurians; but, on the whole, the deep-sea fauna cannot be regarded as older than the other faunas of the seas. The hopes that were cherished of finding living ichthyosauri or plesiosauri, or the Devonian ganoid fishes, or at least a trilobite, or some of those curious fossil echinoderms, the cystoids and blastoids, must be given up. Certain of the larger groups peculiar to the deep sea have probably been there since remote times; but many of the inhabitants of the deep belong to the same families, and even to the same genera, as their shallow-water allies, and have probably descended in more recent times. There, in the deep dark stillness of the ocean bed, unruffled by secular change, they have developed and are developing new modifications and new forms, which are as characteristic of the deep sea as an Alpine fauna is of the mountain heights.
BRITISH SEA-FISHERIES
ἂγει
. . . πόντου τ' εἰναλίαν ϕύσιν σπείραισι δικτυοκλώστοις,
περιϕραδἠς ἀνήρ.
Sophocles: Antigone.
To contemplate all the legislation concerning English sea-fishing and the administration of this vast industry during the last century is alike to bewilder the reason and to fatigue the patience. The industry is an enormous one, and of the utmost value to the dwellers in these islands. At the present time there are over 27,000 vessels, manned by more than 90,000 seamen, fishing from the ports of Great Britain. They land over 900,000 tons of fish, worth some £10,000,000, during the year. In addition to the fishermen who remove the fish from the sea, a considerable population of packers, curers, coopers, hawkers, etc., is employed. For instance, out of the 20,000 hands employed in the Shetland herring-fishery summer of 1906, 11,000 have been at sea, and 9,120, of whom 7,560 were women, have been employed on shore, not to mention the large number of railway employés who are engaged in the transport of a very perishable article. Apart from the material interests of the trade (the capital invested in steamers, sailing-boats, and gear of all kinds being estimated at more than £11,000,000), the fishing industry is of great importance to the country as a training-ground for sailors and marine engineers, and as affording a means of livelihood to a vigorous and an independent population.
Like any other industry, and—because the life-history of the inhabitants of the sea is still so obscure—perhaps more than any other industry, sea-fishing is liable to arbitrary fluctuations. There was, for instance, a partial failure in the herring-fishery in the summer of 1906 on the north and north-east of the Shetlands. The total number of crans landed was 438,950, as against 632,000 in 1905, a record year; and some of the Shetlanders have been hard put to it to live. Such a failure sets thinking those whose livelihood is threatened; but fishermen, although keen observers in what immediately concerns them, are not widely educated men, and cannot take into account in estimating causes, the many factors of the problems, some of which usually escape even the most talented of marine biologists. Fishermen seek a sign, usually an obvious one; in the present case, the bad season was attributed to the presence of certain Norwegian whaling companies, which a few years ago established themselves in the Shetlands and are destroying the common rorqual, the lesser rorqual, Sibbald’s rorqual, the cachalot, the humpbacked whale, and more rarely the Atlantic right-whale. These are killed for their blubber; the flesh is made into sausages, largely consumed in Central Europe; and the bones are ground up for manure.
It is, however, doubtful if whaling is in any way responsible for the scarcity of the herrings. According to the evidence collected by Mr. Donald Crawford’s Committee on this subject in 1904, it would appear that practically the only point on which the fishermen were then agreed was that the spouting of the whales was often a good guide as to the position of the herring-shoals. But the whales do not bring the herrings; and the fishermen are not even agreed that they serve to concentrate them. It is probable that the general migrations and shoaling habits of the herrings are far more dependent on the physical character of the water—a relation which is particularly clear, as the international investigations have already shown, in areas where sharply contrasted ocean-currents are constantly striving for the mastery as they are in the neighbourhood of the Shetland Isles. The hydrographical bulletin of the International Council recorded a distinctly lower temperature for the Atlantic current between Iceland and Scotland at the beginning of the year 1906 than at the corresponding season of 1903, 1904, or 1905; and an unusually low temperature has been characteristic of the Shetland waters throughout the summer of 1906. The Gulf Stream could more justly be blamed for the comparative failure of the Shetland fishery in 1906 than the Norwegian whalers, whose operations have probably done no more injury to the herring-fishery than they did in 1905 or the year before. Such failures are often real disasters to a seafaring population—a race who are, as a rule, of small versatility and unable to turn readily to new trades. Their occurrence usually provokes a cry for legislation.
Such an outcry is in this country usually met by the appointment of a Commission, or of a special Parliamentary Committee. Seventeen such inquiries into sea-fisheries have been held since Queen Victoria came to the throne, an average of one every four years. The usual process is gone through; a certain number of more or less influential gentlemen (one of them perhaps an expert) are given a ‘wide reference,’ and they proceed to take evidence. An energetic secretary, usually a young barrister, collects facts; a great number of witnesses, like Mrs. Wititterly, ‘express an immense variety of opinions on an immense variety of subjects.’ These are written down and printed; and the Commissioners, with the aid of the energetic secretary, seek to distil wisdom out of the printed evidence of the multitude, and base on it their recommendations. Legislation is sometimes recommended; but in the case of the sea-fisheries of this country it has, perhaps fortunately, seldom followed the presentation of any of these reports.