Important though the beam-trawl may be, there is another mode of deep-sea fishing which deserves to be well known by us in Australia, and which undoubtedly must come into general use before we can make any pretensions with regard to our fisheries. I refer to that by means of drift-nets. As the trawl is absolutely necessary, on the one hand, for capturing fish which frequent the bottom, so, on the other, the drift-net is essential for those whose resort is the upper portion of the sea. It is by this method alone that fish like the herring, the mackerel, and the pilchard--which may be termed surface fish--are caught in great quantities for food supply.
Now, in Australia, we have vast shoals of migratory fish visiting the coast at different periods of the year. During the winter season enormous numbers of herrings come to these shores, and are permitted to depart without any effort being made to capture them. Attention has been repeatedly called to this strange neglect in our fisheries, for this herring is plentiful and is considered to surpass the famous Scottish herring itself in flavour. The mackerel, too, is to be met with annually, generally about midwinter, in immense shoals, passing near the coast upwards in a northerly direction. The sea mullet also makes its appearance towards the end of the summer months, usually from April to June, at the very time when it is in splendid condition and full of roe. It is always observed to be proceeding towards the north in successive shoals and in great numbers. Many consider its richness and delicacy of flavour to be unequalled. The driftnet system of fishing would be well adapted for it--if the meshes were larger than those for the herring--as when fully grown it is nearly two feet in length. And lastly, it will only be necessary to speak of the "maray,"
which is practically the English pilchard. As with the fish just mentioned, it is met with about midwinter, passing up north in countless numbers, sometimes covering miles of sea.
As the name implies, drift-nets are not worked from the shore, but they are "shot," as the saying is, in the open sea, and allowed to drift in whatever direction the tide may take them. Each drift-net will measure about 180 feet in length by about 30 feet in depth. They are secured to one another at the ends to form a long single line, perhaps two miles in length. By means of floats the nets hang perpendicularly in the water, thus forming a long wall against which the fish "strike,"
and get enmeshed by being caught in the gill opening. The nets are kept on the stretch by being "shot" in the face of the wind, and the vessel from which they are paid out, being to leeward of them, drifts more rapidly than they do, and consequently keeps them well extended.
My object, however, is not so much to enter into the details of these different methods of deep-sea fishing as to indicate their value and necessity, if we are to have any fisheries worth speaking of. I shall, therefore, do no more than briefly mention a few other modes of fish capture. Thus, at the mouth of the Thames, thousands of tons of sprats are caught every winter by means of the large bag net, known as the stow net. In shape it is like an enormous funnel, 30 feet high, 20 feet wide, and nearly 180 feet in length. By means of this contrivance the yield of sprats is so great that there is often some little difficulty in disposing of the catch. The renowned whitebait, too, which are believed to be young herrings, are caught by means of a similar, though much smaller, net.
Besides these and various other forms of net fishing, there are the methods in which the long line is employed. For the capture of the cod, both in Newfoundland and in the North Sea, what is called the bultow is used. This is a long line many hundreds of-feet in length, and at every twelfth foot shorter and smaller cords called "snoods" are fastened.
These "snoods" are about 6 feet long, and have the hooks attached to their free ends. The bultow is "shot" across the tide to prevent entanglement of the hooks, and is laid in the afternoon. At daybreak, when the lines are hauled in, as many as 400 of the large cod sometimes result from the catch. There are various other appliances used for fish capture in different parts of the world, such as the purse-seine net, the trammel net, the otter-trawl net, &c.; and, as I have already pointed out, the most scathing satire on our fisheries is to find all these necessary means for catching fish regarded as curiosities. When they are no longer considered so, it will be a fortunate time for Australia.
BENEFITS FROM THE DEVELOPMENT OF OUR DEEP-SEA FISHERIES.
What would the proper development of our deep-sea fisheries mean? In the first place, it would lead to a more widely diffused use of fish as an article of diet, within the easy reach of all classes, being thus of incalculable value from a health point of view. Next, it would ensure employment to many hundreds, and eventually to many thousands, both directly and indirectly, and as a natural consequence this would bring about the creation of a sturdy and desirable maritime element in our population. And lastly, it would yield a more than satisfactory return on the outlay invested.
At the present time only the veriest few of our metropolitan population are able to afford the luxury of fish, and people in the country towns hardly see it at all. So, too, we are casting about for this plan and for that plan to lessen a growing difficulty in the Australian metropolitan centres. There are village settlements (which certainly deserve to be successful), and other proposals made to relieve a surplus population, but yet no one has suggested the sea as a means of remedying this congestion. And not only would the fisheries confer upon its followers a healthy calling, but they would raise a vigorous stock of which Australia might well be proud. In addition to all this, a proper development of our deep-sea fisheries would assuredly open up a new avenue for investment. Is it not amazing that men will risk all they have in mines which are not even real, and which exist, only on paper? And besides this, in the most genuine mine that was ever worked there is at least a costly outlay for production, for crushing, or for smelting, before the metal sees the light of day; but in the sea the catch is ready for the market, and only requires the bringing to land.
This matter, therefore, must be taken up earnestly, and there must be a determination to succeed. In the first place, and before all else in the deep-sea fisheries, I maintain that a proper and systematic search for trawling grounds is absolutely essential. Till this is done he cannot for a moment pretend that we have endeavoured to foster them in any way. All the elaboration of your proposed Fisheries Acts, and all the details connected with the working of what may be called shore fishing, sink into nothingness when compared with the results which would follow the working of our deep-sea fisheries. I have already used the argument before, and do so again, and it is this: that if you were to take away from the old country her deep-sea fisheries, she would be practically without any fish supply.
Apparently it is imagined, too, that unless trawling grounds be discovered in the vicinity of Sydney or Melbourne, all efforts will be useless. But it will only be necessary to refer to the deep-sea fisheries elsewhere to at once set this objection aside. Some of the great trawling grounds in the North Sea are at such a distance from port that it would be quite impossible for any vessel to bring its own catch to market for disposal, for the fish would be utterly spoiled before it could be done. But the larger trawling boats go on cruises extending over weeks, and are constantly visited on the grounds by what are called "carriers," i.e. steamers, who run their freights directly into market. The same thing is practised by the Dutch vessels, who fish in the neighbourhood of the Shetland Islands for weeks together. In the same way carrier vessels attend upon their fishing fleets, and carry off the take immediately to Holland. Being in possession of these facts, therefore, we must not be induced to believe that deep-sea fishing is not possible, simply because suitable grounds for trawling, &c., may not be actually within coo-ee of the Australian metropolitan centres.
FISH MARKETS OF SYDNEY AND MELBOURNE.
There are one or two matters in connection with this subject which deserve having attention called to them. In the first place the method adopted in our Woolloomooloo Fish Market of placing the fish in little heaps on the floor itself, when put out for sale, is not satisfactory.
In the Redfern Fish Market they are placed in small divisions or receptacles--each lot by itself--and raised above the floor, where they are protected from injury. In the new Melbourne Fish Markets, there are elevated platforms for the fish, and they are thus quite above the cemented floor. Not only are they prevented from being damaged, but it seems to me that the buyers have a better chance of seeing the fish when it is raised a little distance above their feet.
The size of the fish lots for sale in the Sydney and Melbourne Fish Markets varies, and this opens up a somewhat debatable point. with us the lots are comparatively small, both at the Woolloomooloo and at the Redfern Market; while at Melbourne, on the other hand, the lots are much larger. When the lots are small it gives private buyers a chance of purchasing (but how many private buyers are there before breakfast?), and is said in this way to raise the price for the dealers. But with the larger lots the latter are said to be able to buy to more advantage, and thus supply the public with cheaper fish. To say which is the better of the two plans is very much like being asked to solve the query in the story of "The Lady or the Tiger."
But before leaving this matter I should like to refer briefly to the new markets in Flinders Street, Melbourne. They are called the City of Melbourne Meat, Fish, and Farm Produce Markets, and are most extensive in area. The viaduct which connects the two railway systems of Victoria pierces the very centre of these new markets. They are replete with every modern appliance for the storage and disposal of the food supply of a large city. There are numerous chambers for the frozen meat, and by means of what is called a "lock," a whole train can be received into a long covered gallery. The two gates are then closed at either end, and the meat is thus received directly into the freezing chambers, without the slightest loss of any cold air. The fish and game are treated exactly in the same way, except that the receiving and delivery "locks" are not quite so large as in the former case. Still, there is just the same facility for their reception into the freezing chambers set apart for the purpose. The whole arrangements of these new fish markets are very perfect, and leave nothing to be desired.
THE "MIDDLEMAN" CONTROVERSY.
This is one of the topics which is continually cropping up in connection with the fishing industry in Australia. It is noteworthy, too, that the middleman in some shape or form appears to be part of the system of fish selling in every part of the world. At Billingsgate, where they are termed "bummarees," it is stated that they fulfil a useful office in that they act as distributors to the small costermongers, who could hardly get along without them. The "bummarees"
watch the market and speculate accordingly, and it must be urged for them that they run great risks from the unexpected arrival of a large amount of fish with a consequent glut in the market. But the "bummarees" pure and simple are comparatively few. Their ranks, however, are swelled in the following way: A salesman, having disposed of his own fish, will "bummaree" for the sake of the possible profit, or a fishmonger, having purchased a double supply for a cheaper price, will "bummaree" half his purchase. In France the procedure is different. First of all there is an agent termed an ECOREUR, deputed by various persons and armed with purchasing power, who is ready to buy the fisherman's catch at once. This simplifies matters wonderfully for the fisherman, who gets ready money and has no further bother. Next, from the ECOREUR the fish is bought by the MOREYEUR, or trader, who despatches it to Paris and the other large cities. Thus, so far, the fish, after leaving the fisherman, has passed through two hands, those of the ecoreur, and those of the MOREYEUR. After this it has to face a most unjust tax--the OCTROI--by which all provisions are specially taxed before entering the "barriers" of any French city or town. Hence the initiated, when travelling in France, often reside on the outskirts of a town, just outside the barrier, where the cost of living is reduced by one-third. On arriving at the markets the fish is publicly disposed of by the FACTEURS A LA CRIEE, or auctioneers, who of course are paid for their trouble. Lastly, it is bought for sale to the public by the POISSARDE, or fishwife. And thus we see from the time of leaving the water till finally it reaches the unfortunate public the fish has passed through no less than six levies, that by the fisherman, the agent, the trader, the OCTROI (I.E. the city toll or town due), the auctioneer, and, finally, that by the fishwife or costermonger.
Having thus explained the system pursued in England and in France respectively, it will be interesting to refer briefly to the different methods with regard to the disposal of fish practised in the Woolloomooloo, the Redfern, and the Melbourne Fish Markets. At the former, the sales are conducted by Mr. Richard Seymour, the inspector and auctioneer of the fish market--with other auctioneers--who act directly from the Sydney Municipal Council; the Redfern markets are conducted by the Messrs. Hudson; while in Melbourne there are licensed auctioneers, who pay for the privilege.
But to return to our middleman, upon whom the whole controversy centres. Indeed, the discussion over him in Melbourne, not so long ago, might be said to have reached to a white-heat phase. But the. premises on which the arguments were based were so hopelessly conflicting that it was impossible to logically settle the point. It was claimed, on the one hand, that the price the fishermen received was cruelly small in comparison with that which the public had to pay. On the other, the contention was that the price paid to the fishermen was fairly satisfactory, and that the public obtained comparatively cheap fish. We have seen, however, what takes place in other parts of the world, and, indeed, every one must admit that there is a remarkable difference between the price which the fisherman gets and that which the public have to pay. Between these two extremes there is an inordinate disparity, and the difficulty is to connect the two together--to bring to light the leakage--and to find out who is living both on the fisherman and the public at one and the same time. On this point a recent Fisheries Report of Victoria says:--"The solution of the very important question of providing a larger and cheaper fish supply for the masses rests mainly in the hands of the public. The present high prices are maintained in virtue of a monopoly which can be only successfully combated by the initiation of a healthy trade competition or a more open fish market. The fishermen, under existing auspices, reap but a small share of the retail produce of their takings, such being further reduced by the high rates for transport they are called upon to pay. In this last-named direction some relief might be afforded by the institution, if necessary by Act of Parliament, of a uniform tariff for the carriage of fish by road and rail throughout the colony."
THE DISTRIBUTION OF FISH TO THE PUBLIC.
This brings me to one of the most difficult matters that has to be dealt with in considering the fish supply of any great city. For you may have the most extensive deep-sea fisheries, you may have the most rapid transit of the fish to town, and you may have the most commodious fish markets; but if you have no proper means of distributing the fish to the public the whole scheme falls to the ground. At present the system both in Sydney and in Melbourne is to have the one principal fish market (there are now two in Sydney, by the way), from which all supplies for the public are derived. Of course it is perfectly competent for the latter to obtain their purchases in the early morning at the time when the sales are conducted; but, on the other hand, the hour is exceedingly inconvenient, and, as a general rule, the lots are too large for the private buyer. Hence the distribution of fish depends almost wholly upon the costermonger or basket-man, who takes his fish round to the public. The basket-man, or costermonger, or dealer--call him what you will--is an indispensable personage, and what is more, he fills a most useful office. It is true that he is given to making strange outcries, and that he is at times boisterous in speech. Yet, notwithstanding these things, he is a valuable member of society, and personally I have a very great respect for him. Indeed, I am certain that he is the food-bearer to many homes, and people would otherwise be put to very great straits in obtaining their supplies. Our friend, however, has usually a long round to travel before he can make a good living, and perhaps he is unable to cope with the requirements of his large district.
It is on account of these difficulties, therefore, that I recognise the value of the French method of distribution, for besides the Halles Centrales, or principal markets, in Paris, there are in all nearly sixty local provision markets where it is possible to obtain, under cover--in all weathers and at any time--whatever is required. It is most desirable that something of this kind should be adopted in Australia. At least it is quite certain that every suburb should possess its own local market. This need not attempt to rival the central depot, but take rank as a local necessity.
FISHMONGERS AND THE SALE OF FISH.
This is naturally in intimate connection with the preceding, and it is very advisable to refer to it in order to direct attention to one or two matters. In the first place, I shall commence by saying that both Sydney and Melbourne are lamentably deficient in fishmongers' shops similar to those which are so common in London. As a matter of fact, the show of fish exposed for sale is in striking contrast to that of meat. For in Sydney and suburbs alone the butchers' establishments run to the number of nearly 600, while in the Melbourne metropolis they even exceed this. One has only to look through the directories of either Sydney or Melbourne, under the heading of "Fishmongers," to see how few their numbers are. In our own city, Chinnery, of Hunter Street, and Matterson, of Pitt Street, make a highly creditable show, and in the southern capital, Jenkins, of Swanston Street, is well known for his excellent display. Otherwise the exhibition of fish for sale in either city is disappointing in the extreme, and is nothing less than an abject confession of our inability to develop our own natural resources.
There was formerly in Melbourne, however, a most admirable firm known as the Mutual Provedoring Company, whose premises were centrally situated near the main suburban railway station. Their show of fish was something to behold, and I do not remember to have seen it surpassed, even in the old country; and, in addition, they hit upon a very excellent device--one so good, in fact, that it is well worthy of imitation. That is to say they gave to every customer a capital fish cookery book, written, indeed, by our own Mrs. H. Wicken. It was a well-compiled production, and contained a goodly number of practical and economical recipes, having special regard to our Australian fish.
In this way they did splendid work, as by means of the FISH DAINTIES (the title of the book) they popularised the use of fish. Now, it is greatly to be regretted that this firm no longer exists, because if ever there was a venture which deserved support, it was surely this.
But I am no pessimist in these matters, and verily believe that before long this company, or one similar, will be in full swing again, and that the public will thereby benefit in every conceivable way. As far as Sydney is concerned there is a different state of affairs, and it is with genuine pleasure that I refer to the New South Wales Fresh Food and Ice Company, of whose enterprise and praiseworthy efforts I must express my sincere approbation. It is a good thing for the whole community that their endeavours have been crowned with such marked success; and I am very certain that, without any exaggeration whatever, one is justified in saying that this company have been of unmistakable service to their numerous customers, and that by their distribution of fish throughout New South Wales, quite a number of invalids, as well as of healthy people, have every reason to be grateful. Their exhibition of fish in King Street is at all times most satisfactory. Moreover, schnapper and other prime fish are often sold there as low as 4d. per lb., a price at which no one can complain.
THE DEVELOPMENT OF THE OYSTER.
Attention has been thus far entirely directed to the topic of fish, so that it now becomes necessary to turn to that of oysters. It will be found, however, that the actual state of affairs in connection with our oyster fisheries is not at all inspiriting. But before entering upon this matter it will perhaps lead to a better understanding of the whole question if some preliminary remarks are made upon the subject-heading.
In doing so it will be most desirable to have recourse to an account given, not so long ago, by Professor Huxley--at that time Inspector of Fisheries--since he speaks with the weight of authority. Referring to the oysters in the old country, he says that during the summer and autumn months, from about May to September, according to varying circumstances, the oysters pass into a peculiar condition known to the fishermen under the name of "sick." In this state the greater number contain a whitish substance, consisting of numberless granules held together by a sort of slime. The whole is known as "white spat," and the numberless granules are really the oyster eggs. Slowly and slowly the interior of the eggs assumes a darkish hue, tinging the whole mass so much that it is then termed "black spat." Within the space of a fortnight the mass of "black spat" breaks up, and the young oyster is set free.
Mr. Frank Buckland has been fortunate enough to actually see this taking place. The oyster appears to await its opportunity, it stealthily opens its shell, and a lot of spat looking like a dense cloud is ejected. After a minute or two another cloud appears, and this is continually repeated till the performance is concluded. Myriads of young oysters thus liberated from parental control now enter upon the free swimming or locomotive stage of their existence. That is to say they remain near the surface of the sea, although incessantly moving in every direction.
After a variable time, however, they suddenly descend and attach themselves to any suitable substance, on which they at once become distinctly visible in the form of white dots. In their restless stage they are scarcely discernible by the naked eye, but they settle down so rapidly and in such numbers that they appear to fall down through the water. This is known to oyster fishermen as a "fall of spat," and we shall see that this fall of spat is an important occurrence, but that it varies greatly in different seasons.
THE FAILURE IN THE NEW SOUTH WALES AND VICTORIAN OYSTER SUPPLIES.
In both New South Wales and Victoria the condition of affairs in connection with the oyster fisheries and the oyster yield is extremely discouraging. So much so, that unless something is done--and done quickly--we may have to rely mainly on outside resources for our supply. Even at the present time this is the case to a greater extent than most people have any idea of. In support of this statement, as far as New South Wales is concerned, it is only necessary to turn to the last Fisheries Report for the year ending 1890. There it is pointed out that in that year, notwithstanding the enormous length of our oyster-bearing foreshores, we are brought face to face with the fact that we are indebted to other colonies--New Zealand and Queensland-- for TWO-THIRDS of our supply. Again, Mr. Lindsay Thompson, the chief inspector of New South Wales fisheries, in his recent official work, THE FISHERIES OF NEW SOUTH WALES, makes the following statements:--In the year 1871 no less than 93,000 bushels of oysters were obtained from the New South Wales beds, which, indeed, helped to supply the Victorian as well as our own needs; in the year 1883 there was a fall to 46,377 bushels; while in 1891 our fisheries yielded only 14,181 bushels. This is a very significant shrinkage, and shows a remarkable falling off in the winnings. It is still maintained by some, however, that there has been a succession of bad spatting years, and that the supply may yet reach to something of its old proportions.
It will be instructive, then, in this connection to refer briefly to the efforts which legislation has made to remedy matters in New South Wales. Under the old Oyster Beds Act of 1868 the areas given to lessees were somewhat large, and consequently what with the prolific natural supply, and a relatively small population, they appeared to be doing too well. It was urged, therefore, that the holdings should be more restricted in size, and that in this way a large number of small occupiers would be afforded a means of living, while at the same time these smaller areas would receive more attention. By the Fisheries Act of 1881 a new era dawned upon the oyster fisheries of this colony, and a system of licensing small holdings was initiated. Under this Act licensed dredging was permitted, but with such disastrous results that within two years a Fisheries Act Amendment Act had to be passed. What happened, in short, was that the beds were actually skinned, so that the total disappearance of the oyster was looming in the distance. But even the passing of this latter Act was powerless to check the evil, and by the Oyster Fisheries Act of 1884 (the present Act) there was a reversal to the old system of long leases and larger holdings.
Even at the present time matters are far from perfect, and in the opinion of the Commissioners of Fisheries some radical change is necessary if oyster production is to have a place at all. Now, it is true that the present Act has checked the wholesale extermination of oysters on the part of licensed dredgers. But, unfortunately, in its passage through Parliament, some unhappy amendments totally altered the intention of the Bill. For instance, one clause makes it penal to remove oysters from a reserve or leased area without authority; but omits the protection of oysters on adjoining foreshores which may not be under lease at all; and it has accordingly happened that unprincipled persons have proceeded to rob the adjacent unleased beds of every single oyster they contained.
But while faulty and inoperative legislation may be responsible in part for the failure in our oysteries, it is certain that other causes must be at work to bring about such a disastrous result. And in the different annual reports on the fisheries of the colony this is attributed to various reasons. Thus at some places, between the Richmond and Port Macquarie, it has been set down to the presence of quantities of decomposing sea-weed on the oyster beds; in the Manning to deposits of mud and sand; and elsewhere again to the ravages of a small worm. Besides these causes, too, it has been ascribed to the long continued absence of floods, with a consequent increased salinity of the water--the latter being considered inimical to oyster life. In the opinion of scientific writers, water containing 3 per cent. of salt is most suitable for oyster development, water above that salinity being too strong, and that below it too weak. It has also been well pointed out by Mr. henry Woodward, in his admirable pamphlet on Oyster Culture in New South Wales, that most of our deep water beds are situated in the rivers, a little way from the sea. Under favourable circumstances there is just that commingling of the fresh water from the river and the salt water from the sea which produces the oyster to perfection. In times of drought, however, the salt water drives out the oysters from the deeper beds by reason of its greater density. On the other hand, the fresh water, being the lighter, floats at the top and enables the oysters to live in the shallower parts, by maintaining the required 3 per cent. of salinity. It is evident from this, that the lessees have acted in direct opposition to this natural law, for they have stripped the oysters from the shallow water, where they would have done well, and laid them down on the deep beds, where the increased percentage of salt water has proved too much for them.
Dr. James C. Cox, of Sydney, the President of the Fisheries Commission, and our best known authority on conchology, has contributed a very valuable paper upon "The Australian Oyster, its Cultivation and Destruction," to the recent official work, THE FISHERIES OF NEW SOUTH WALES, already referred to. A brief summary of his views will, therefore, be full of interest. First of all, then, he separates oysters into three classes, namely, drift oysters, mud oysters, and rock oysters. Now, this classification must be clearly borne in mind, as it will the better enable the reader to understand what follows. He attributes the want of success in our oysteries to several causes, which have not been sufficiently heeded. One of these is that the oyster culturists have expected that the seed oysters which they obtained from between high and low water mark (rock oysters) would produce drift oysters if placed on beds on which drift oysters once throve in abundance. Dr. Cox maintains, however, that these two kinds of oysters, the rock oysters and the drift oysters, are quite different, and, as it will be seen, believes that they require different food. It can be well understood from this, then, that rock oysters will fail to grow on drift-oyster beds.
As to the mud oyster, he thinks very highly of it, and regrets that it has been so ignored by our oyster culturists. He is quite sure that if our mud oyster were cultivated and educated as it is now in Europe, it would be brought to the same perfection as the European and American oyster. It has been said of our mud oyster that it will not keep, and will not carry; but the same was said of its European representative until its cultivators came to discover that by a gradual process of raising it could be educated to keep quite long enough for all commercial purposes.
To come to the real point on which Dr. Cox considers that all oyster culture has failed in Australian waters. It is an established fact that the drift oyster and also the mud oyster require a diatomatic food for their existence. These two varieties of oysters no doubt consume other forms of food, but living diatoms constitute by far the greatest part.
On the contrary, the rock oyster does not appear to need the diatomatic nutriment to sny extent, and is fed chiefly by larval forms of marine life. Thus, knowing that the drift and mud oysters require different food from the rock oyster, it is easy to see why our oyster culturists have failed in establishing new beds of oysters in various places. For the whole purport of Dr. Cox's paper may be summarised into expressing his belief that sufficient attention has not been devoted to the replenishment of our natural beds, WITH THEIR OWN KIND.
In former days, when our drift and mud oysters were in their prime, there were many pools of naturally preserved fresh water--in fact, often very extensive lakes--on the banks of many of the estuaries and inlets running up into our rivers and creeks. Now, these reservoirs appear to have been constantly supplied by subaqueous springs of fresh water, and in consequence the supply of diatomatic food was abundant. It was abundant, because, as it is well known, diatomatic life depends for its existence, to a great extent, on the presence of fresh water. These collections of fresh water no longer exist, so that the diatomatic food supply is not forthcoming to maintain the drift and the mud oyster. But there are other additional causes for the disappearance of these latter. The surrounding ground has been cleared for agricultural purposes, and the earth, broken up by ploughing, has been washed into these estuaries, and has suffocated, as it were, the oysters in their natural position. Again, the water which flows over the oysters is continually being disturbed by the different steamers passing up and down. The stirred-up mud they create gets into the gills, and destroys the oysters.
From the preceding it will be seen that Mr. Cox is of opinion that the loss of diatomatic food is one of the principal causes in diminishing the supply of drift and mud oysters, and in addition he believes that this decrease has been also brought about by muddy water. Indeed, fairly clear water is absolutely necessary for their existence. On the contrary, water loaded with any sediment interferes with the functions of the oyster so much as to destroy it. In this way floods are considered to be beneficial, and even almost necessary, to proper oyster development; for they clear out the accumulations of mud, silt, and marine vegetable growth, thus giving the beds every chance. And further, Mr. Thomas Whitelegge, of the Australian Museum, has made some investigations into what is known as the "worm disease," due to the POLYDORA CILIATA. It was commonly suppose that it was not the worm itself which was fatal, but that by boring through the shell it afforded entrance for the fine mud, which quickly destroyed the oyster.
From the result of his researches, however, Mr. Whitelegge believes that the young worm simply swims into the open oyster, and that it immediately begins to construct a tube and collect a large quantity of mud. The worms appear to have the power of collecting a large quantity of mud in a very short time. The mud is covered over at once by the oyster with a thin layer of shelly matter, thus enveloping the worm, together with its mud. After this, one of two things happens: if the oyster be healthy, it envelops the worm and mud so quickly as to dispose of the intruder for good; but, on the other hand, if the oyster be unhealthy, or already infested, the shelly deposition is far slower, as a consequence of which the worm gains the ascendency, and the oyster succumbs.