“In this dredging, as in most others in the bed of the Atlantic, there was evidence of a considerable quantity of soft gelatinous organic matter, enough to give a slight viscosity to the mud of the surface layer. If the mud be shaken with weak spirit of wine, fine flakes separate like coagulated mucus; and if a little of the mud in which this viscid condition is most marked be placed in a drop of sea-water under the microscope, we can usually see, after a time, an irregular network of matter resembling white of egg, distinguishable by its maintaining its outline and not mixing with the water. This network may be seen gradually altering in form, and entangled granules and foreign bodies change their relative positions. The gelatinous matter is therefore capable of a certain amount of movement, and there can be no doubt that it manifests the phenomena of a very simple form of life.”
“To this organism, if a being can be so called which shows no trace of differentiation of organs, consisting apparently of an amorphous sheet of a protein compound, irritable to a low degree and capable of assimilating food, Professor Huxley has given the name of Bathybius haeckelii. If this has a claim to be recognised as a distinct living entity, exhibiting its mature and final form, it must be referred to the simplest division of the shell-less rhizopoda, or if we adopt the class proposed by Professor Haeckel, to the monera. The circumstance which gives its special interest to Bathybius is its enormous extent: whether it be continuous in one vast sheet, or broken up into circumscribed individual particles, it appears to extend over a large part of the bed of the ocean …”
The ‘Bathybius’ however came to an inglorious end. It was shown by the naturalists of the Challenger to be a precipitate thrown down from the sea-water associated with the deposits by the alcohol used in their preservation, and T. H. Huxley made a public retraction of his earlier ideas.
Towards the end of the century came the founding of the famous marine stations, the first at Naples in 1872, and then those at Plymouth and Millport in this country and Woods Hole in America; in these laboratories and many more to be founded later, researches into the structure, development, physiology, life and habits of marine creatures of all kinds have been continued to the present day.
It then began to be realised that progress in oceanography was essential to a better understanding of fishery problems and to the development of a more rational exploitation of the sea. The rapid development of trawling, with the introduction of steam power and the replacement of the old beam-trawl by the much larger and more efficient otter-trawl, gave rise to some concern as to the possible depletion of the stocks of fish; this led a number of nations, our own included, to set up fishery investigations. As we shall see, those fears were indeed well founded. In 1899 King Oscar II of Sweden invited all the nations of Europe interested in sea fishing to send representatives to a conference in Stockholm; the discussions which took place led to the foundation in 1901 of the International Council for the Exploration of the Sea. The different nations began a series of investigations to form part of one great plan. In spite of the temporary suspension of activities in two world wars the work of the Council still goes on.
The scientists of the various fishery departments are not only enquiring into the natural history of the fish themselves, their life-histories, food and feeding habits, migrations, growth, birth-rates and so forth; but with continually improved equipment they are studying the distribution of the different planktonic forms upon which they depend, the conditions under which they live, the flow of the ocean currents, the physics and chemistry of the sea and the varying nature of the sea-bottom and its life. It was wisely realised from the start that in order to provide answers to such questions as: ‘Why are fish sometimes plentiful and sometimes scarce?’; ‘Can the future of a fishery be forecast?’; ‘Is this or that area being overfished?’ and so on, the natural history of the sea must be investigated in all its different aspects.
Everything the naturalist wants to find out about the conditions under which fish live he must grope for in this unseen world, often below a storm-tossed surface; he must always remember too that the sea is a very big place—he must work with a sense of proportion and perspective. He stops his research ship at intervals to let down his instruments on wires and ropes: some to take the sea’s varying temperature and to collect samples of water from different depths for analysis, others to measure the amount of light reaching different levels, and others again to record the speed and direction of ocean currents. He samples its life with all kinds of nets to estimate not only the varying quantities of the plankton but of the eggs and fry of the fish themselves. Building up a picture of life in the sea is like putting together a huge jig-saw puzzle made up of tiny pieces, but much more difficult. Not only have we a very imperfect idea of what kind of picture will emerge, but all the pieces to be fitted together are not on the table before us; they are lying about somewhere underneath it and we must feel about for them in the darkness. It is certainly a fascinating pursuit, but full of disappointments. Some bits of the puzzle—perhaps a stage in a life-history or some evidence of a migtation—can only be picked up during a short period of the year; before the missing pieces can be found, stormy weather may intervene and we must wait a whole year before we can try again.
In spite of these obstacles the picture of life in the sea is continually growing: the chapters which follow will endeavour to sketch an outline of what has been achieved. The amateur naturalist should not be discouraged by these difficulties for it is because of them that there are so many gaps in the story yet to be filled in. There are still many original discoveries to be made. And the difficulties add spice to the game; a golf-course would indeed be a dull one if there were no bunkers on it.
1 In the “Summary of the Scientific Results of the Challenger” Part 1, p. 79, Sir John Murray refers to the deep dredging of the Erebus and Terror. He says: “Sir James Ross was an indefatigable zoological collector, but it is to be regretted that the large collections of deep-sea animals, which he retained in his own possession after the return of the expedition, were found to be totally destroyed at the time of his death. Had they been carefully described during the cruise or on the return of the expedition to England, the gain to Science would have been immense, for not only would many new species and genera have been discovered, but the facts would have been recorded in journals usually consulted by zoologists instead of being lost sight of as was the case.”
2 Sir John Murray also wrote an excellent little introduction to oceanography: The Ocean (1913). For those who wish to make a fuller study of the development of our science, and particularly of the early plankton investigations by the German Hensen school, there is J. Johnstone’s important book on Conditions of Life in the Sea (1908). Two other valuable introductions should be mentioned: Fowler and Allen’s Science of the Sea (2nd edition, 1928) which gives much practical advice on collecting specimens and the working of gear, and Russell and Yonge’s charming general natural history of The Seas (1928) which deals with the life of tropical waters as well as of our own.
CHAPTER 2 THE MOVEMENT OF THE WATERS
ONE OF THE MOST important features in the world of a marine animal is the movement of the sea itself. Apart from the wave-action near the surface and the to-and-fro tidal streams in shallow coastal areas, the whole water-mass is in continual flow as part of a greater system of oceanic circulation. Carried with the