Gambar halaman
PDF
ePub

productive power is entirely destroyed. This ported. Hence, by the deterioration of the deterioration and impaired fecundity can only beds, not only would the price be much inbe accounted for by the excessive and exhaust- creased for all classes, but the poorer among ive fishery in the sounds, from which hereto our citizens would many of them be thrown fore the beds in the bay have been free. Quite wholly out of employment. probably, were the remaining beds in Chesa To this statistical and historical account we peake Bay examined carefully, they would subjoin a description of the natural history of show indications of deterioration similar to the oyster, with special reference to the procthose discovered in the Tangier and Poco- ess of reproduction, and the conditions influmoke beds.

encing the rate of increase. For material emIt can hardly be doubted that this deteriora- ployed here we are indebted to articles contion is due to the severe fishing, and that in tributed by Lieutenant Francis Winslow. time, unless this is stopped, it will produce ut An oyster-bed, in its natural and undisturbed ter exhaustion. Foreign experience aptly illus- state, consists of a long, narrow ridge of shells trates this. The records of production of the and oysters, lying generally in brackish water, beds of Cancale Bay, on the northwest coast on and surrounded by sticky bottoms, a mixtof France, extending over a period of about ure similar to clay and mud being the most seventy years(1800 to 1868), are very instructive. favorable. The form and area of the bed are The beds comprise an area of about 150 acres, variable, but naturally the length is greater and, from 1800 to 1816, produced annually than the breadth, and the greatest dimension from 400,000 to 2,000,000 oysters. During this is usually in the direction of the current. The period the beds became so thickly stocked that bed itself is made up of masses of shells and the oysters were in some places a yard thick. oysters, covering areas of different sizes, and Subsequently the fishery was much increased, separated from each other by mud or sandand the oysters were removed in larger quan- sloughs, though frequently it is unbroken, and tities till 1843. From 1823 to 1848 it is sup- the animals spread evenly and continuously posed that the dredgers were living on the over the entire area. The oyster thrives best oysters accumulated between 1800 and 1816. in slightly brackish water, and the finest vaIn 1817 the number produced was 5,600,000, rieties are nsually found in water of a lower and until 1843 there was a constant increase, specific gravity than that of the sea. The main the number taken in that year being 70,000,- necessity is that the water should contain a 000. In 1848 it was 60,000,000, and thencé- sufficient amount of lime to furnish the animal forward there was a constant decrease. From with the principal constituent of its shell. 1850 to 1856 the decrease was from 50,000,000 That part of the oyster usually known as the to 18,000,000. From 1859 to 1868 the de- heart is a muscle, called the adductor muscle; crease was from 16,000,000 to 1,079,000, the its office is to keep the valves or shell closed, oysters having almost entirely disappeared, and prevent the ingress of hurtful matter. though the inhabitants, on account of their The two valves are hinged at the round, blunt suffering, dependent condition, were not hin- end of the shell, and between this hinge and dered from fishing. In 1870 there was a com the adductor muscle lies the body of the oyster, plete wreck of the bottom, which could only or visceral mass, which is made up of the lightbe remedied by a total probibition of the fish- colored reproductive organs and the darkeries for several years.

Similar results oc colored digestive ones, packed together in one curred in other places on the west coast of continuous mass. The mouth of the oyster is France, where, when in 1854–55, 15,000,000 that part nearest the hinge, and what is usuoysters were taken from the beds, only 400,- ally called its“ beard " is known as the "gills.” 000 could be obtained in 1863–64. The testi- The oyster lies on its side in the shell, and the mony of English experience also corresponds minute animal and vegetable matter contained with that just given, and is equally valuable in the water forming the food of the animal with reference to the course which must sooner is passed between the gills to the mouth, by the or later be taken in our country for the pres- action of myriads of small vibrating hairs, ervation of the oyster-beds from complete ruin. called cilia. These cover the surface of the

It is true that our beds are so extensive, and gills, and cause a strong current to set into the oysters are so widely distributed and so easily lips of the valves, thus bringing in not only transported and transplanted, that the total what is suitable for food, but other minute parfailure of the American beds must be post- ticles of matter. poned for some time. But the failure of beds The European oyster (Ostrea edulis) and the in different localities may occur at any time, American oyster (Ostrea Virginiana) are variand probably those of Chesapeake Bay will not eties of the same family, and, though differing last many years. The deterioration and exhaus- in several particulars, are not so dissimilar but tion of our beds would cause great distress and that the conditions favorable to the growth inconvenience in the United States, where the and life of one may be considered as equally oyster is no luxury simply, but a means of sup- so for the other. With each variety the formaport to large numbers. Not only are oysters tion of the generative matter is gradual, and consumed with us in every part of the Union, the spawning-season of both is during the early but immense numbers are also annually ex summer months, its advent depending probably

upon the temperature, the higher temperature growth, the animal having passed through its hastening and the lower retarding that event. embryonic life; its organs are formed and in Generally, both in Europe and America, the active operation; it is but immature. The spawning-season may be said to be from June American variety increases more rapidly than ist until August 15th, though variations of the the European. Observations during the sumtemperature and density of the surrounding mer of 1879 in Chesapeake Bay show that, in waters may expand or contract that period the first three months of existence, the oyster considerably

increases in size from a hardly visible speck to All authorities upon the early stages of the an average length of one and a quarter inch, and European variety concur in the statement that a few were over two inches long. After the first the young oyster, or “spat,” is formed by the year the increase is not so rapid, and oysters fertilization of the eggs of the female while of two or three years of age are about two within the shell of that animal, and that the inches broad and three inches long. In three “spat” is held between the gills and thus pro. years, at the most, the American oyster is contected by the parent until the shell is formed. sidered mature. With the European variety Many authorities are also of the opinion that the growth is much slower, and at maturity the parents are hermaphrodites; but the accu- they are very much smaller than the American racy of this view is open to much doubt. The oyster. most material difference between the Euro With all animals Nature strives to provide pean and American varieties is in the manner against the destruction of the young after birth of impregnating the eggs of the female. Ac- by insuring a sufficient number to allow for all cording to the best authorities, the eggs of the ravages; and the greater the danger to the imEuropean variety are fertilized by the passage mature the larger will be the number provided of the male fluid into the water, and thence to meet those dangers. Hence, as the embryo between the valves and gills of the female. European oyster receives some protection and The young resulting from the union of the ova the American none, it is inferred that the and spermatozoa are held and protected within number of American embryos in any commathe gills of the female until the shells are nity will be subjected to greater danger, and formed, and until they are quite well advanced consequently it is probable that a larger numin development, having at the time of their ber of eggs and spermatozoa are provided, that expulsion locomotive powers of their own, the production may not be less. Investigations which enable them to swim about and seek a seem to support this conclusion. Professor fit place for attachment.

Möbius, in his work on the oyster and oysterThe American variety differs in this, that culture, estimates the number of eggs spawned the young oyster is not found within the gills by the European variety as nearly 2,000,000, of either parent, nor does the fertilization take and his estimate is supported by Eyton, in his place within the shell, but the contents of the “History of the Oyster and Oyster Fisheries." generative organs of both sexes are expelled Professor Brooks estimates the possible numinto the water, there to stand the chance of ber of eggs spawned by the American variety coming into contact. It is evident that a large to be as large as 60,000,000, and the average measure of protection is afforded the young of number to be over 9,000,000, or about nine the European variety by the inclosing shells of times as many as the European variety spawns. the parent, and that this protection is given The number of embryos surviving and maturduring the most precarious stages of their ex- ing can not be accurately stated for either vaistence, while the ova and spermatozoa of the riety, as we have not data sufficient to deterAmerican oyster are not only left to a happy mine the question. The results, however, of chance for their successful union, but the re- Professor Möbius's examinations of the Schlessulting young are exposed, unprotected, to all wig-Holstein beds are valuable and suggestive. the vicissitudes of climate, and to the ravages These were made by government officials from of all enemies.

1730 to 1852, in the following manner: Each After the formation of the shell and the de- bed was dredged over in three or six places, velopment of the locomotive powers, the young according to its size, and the oysters taken of both varieties begin their search for a per- were divided into three classes, and carefully manent resting-place or point of attachment. counted. The classes were styled marketable, Such points of attachment must soon be ob- medium, and young growth. The first were tained, or the young oyster perishes. Any the full growth and mature, from two and moderately rough, hard substance, provided three quarters to three and a half inches in the surface is clean, is suitable for the purpose, length and breadth, and about seven tenths and such objects, placed so as to attract the of an inch thick. The medium oysters were young brood, are called "cultch.” Pieces of those half grown, from six to seven tenths of wood, planks, stones, old shells, tiles, etc., have an inch thick, and about three inches in been successfully used. Upon finding the breadth. The young growth were those of “cultch," the "spat" attaches itself firmly, one or two years old. and thenceforward, so fa as its own power is From these observations, made annually, concerned, is located for ever.

Professor Möbius discovered that there were The development is now one of ordinary on an average 421 medium oysters to every

1,000 marketable ones—that is, out of every

The French Government assumes control of 1,421 oysters, 1,000 were full-grown. And he all oyster-beds and fore-shores. Dredging is gives it as his decision that about 1,000,000 fixed for a certain time, which is determined by eggs are spawned by each oyster, and that the local commission. 'A third or a fourth of about 44 per cent of the oysters on a bed a bed buoyed off each year, and dredged spawn each season. From the above it is evi- only for removing weeds, mud, vermin, etc. dent that 1,000 oysters would void every sea The remainder of the bed is open to all licensed son 440,000,000 eggs, and that only 421 of the persons for a specified time. The following resulting embryo would survive, or 1,045,000 year another part is reserved, and occasionally eggs would perish where one survived. But portions are reserved for longer periods. In the medium oysters also spawn, though send- accordance with government regulations the ing forth a less number of eggs, and Möbius beds are not to be opened for fishing until the estimates that 421 in the community would "spat” has acquired strength to resist the acproduce about 60,000,000, or the 1,421 would tion of the dredge, say until the end of Januspawn together about 500,000,000 eggs, and ary. A bed with well-established breeding from these 500,000,000 only 421 oysters would qualities has a fourth or fifth part of its area be produced, or, where one oyster arrived at set apart as a reserve, and dredging over such maturity nearly 2,000,000 eggs or oysters per part is prohibited. A fishery guard-boat is exished !

pected to take part in the working of each Some efforts have been made to obtain data bed. A bed encumbered with weeds or other in regard to decrease in number and increase noxious matter is opened for dredging until in size of American embryo oysters. These cleansed. Beds on which there is never any efforts were put forth in Tangier and Poco production of “spat are to be kept open moke Sounds in the summer of 1879, when a through the season, and after working any number of earthenware tiles were deposited as bed it is required to be examined, and, if nec" spat"-collectors. On inspection it was found essary, the “ cultch” replenished. The closethat the oysters continued attaching until about time is between May 1st and August 1st, and the 20th of August, and that the largest num is strictly observed. ber attached about the first of the month; be By these means the beds on the French coast tween August 23d and October 10th the more have been much improved. It may be well to tality was shown to be fully 50 per cent; fut see how foreign experience can be utilized for ure examinations of the "spat "-collectors will our good in this matter. probably show a diminished mortality, as the The deterioration of an oyster-bed and its animal will be better able to protect itself as it impaired fecundity will be shown in five sev. increases in size, but the destruction among eral ways: 1. By the general appearance and the unprotected, delicate embryos must be im- condition of the beds and animals, the prevasense, and (as it is as great as 50 per cent lence of mud and sand, the oysters being large after attachment) it must be much more serious and single, and the shells covered with worms, prior to that event.

etc. 2. The ratio of young to mature oysters Lieutenant Winslow gives, as the result of will be abnormally large or small. 3. The his observations in 1879, that on a natural amount of débris in the bed will be very large unworked bed the ratio of young oysters to (say as much as 50 per cent of the contents of those of mature age is as one to two, or where the dredges). 4. The number of oysters on there are 1,500 oysters 1,000 would be matured the beds will be found to decrease each year. and 500 young. Professor Brooks estimates 5. The discovery of unusual inhabitants of the the number of eggs voided by the American beds other than oysters, or, in general terms, oyster at from 9,000,000 to 60,000,000; 10,000,- marked changes in the fauna of the beds, indi000 may be taken as an average. The 1,000 cate deteriorations. In cases like these protecmature oysters in the community would then tion must be assured in order to prevent entire spawn 10,000,000,000 eggs, and as the young destruction. If deterioration is due to excesEuropean oyster has been found to spawn about sive fishery, that must be prohibited; but, as one third as many as the mature animal, we many of our poorer fellow-citizens find supmay consider the same to be true for the Ameri- port in this industry, restriction manifestly can variety. The 500 young would then spawn must be used, not entire prohibition. The 1,600,000,000 eggs, or the total number in the larger the area, of course the less exhaustive community would spawn 11,600,000,000 eggs, will be the fishery in any particular locality, from which would result 500 oysters, or about for the fishermen will naturally leave old and 20,000,000 eggs or oysters would perish where worn-out beds and seek for those newly disone was preserved. Lieutenant Winslow's ob- covered and well stocked. Fortunately for us, servations convince him that the beds of Po- the area covered by oysters along the coast of comoke Sound at least are in a condition very the United States is so great that at present similar to the French beds before they were when any bed or locality begins to fail the subjected to the action of protective laws. As fishery is transferred to other points. This is these have been made to yield again a profita- shown by the fact that vessels have left the ble return, it may be weil here to take note sounds and work now in the beds in Chesahow protection is rendered effectual.

peake Bay.

In time, however, the entire areas will be special knowledge on this subject, should be known, and all future extension of the fishing- appointed; and a fishery-guard should be put ground will be artificial in these areas. New under their control. This commission should beds will probably be found off the mouths of endeavor to prevent exhaustive dredging; to creeks or rivers, and not far from beds already secure the reservation of beds containing a known. The extension of old can be effected large number of young growth; to put a stop by depositing suitable "cultch" upon the bot- to the removal of the young growth; to enforce tom near the beds, so as to afford a place for the strict observance of the close times; to see the attachment of the drifting "spat." Stones, that the beds are cleansed before the advent ballast, old shells, etc., make excellent cultch, of the young brood; to have exposed suitable which should be exposed late in the spring. A “cultch " when the bed has been long worked; number of mature oysters being deposited with and to destroy star-fish, drills, etc., that may the shells, materially aid in extending the beds. exist on the beds. The following warning is

As the consumption of the oyster is con- given by Professor Möbius: “In North Amerstantly increasing, any failure of supply will ica the oysters are so fine and so cheap that of course add to the price and induce exhaust- they can be eaten daily by all classes; hence ive fishery; and in time it will become so great they are now, and have been for a long time, that strict protective laws, rigidly enforced, a real means of subsistence for the people. will be required in order to prevent the destruc- This enviable fact is no argument against the tion of this branch of industry.

injuriousness of a continuous and severe fishInasmuch as legislation on this subject will ing of the beds. . . . But as the number of probably be needed ere long, Lieutenant Wins- consumers increases in America the price will low suggests several points worthy of consid- also surely advance, and then there will arise eration. Organized and systematic efforts the desire to fish the beds more severely than ought to be made to discover new beds and to hitherto; and if they do not accept in time extend the old ones. Experiments also, look- the unfortunate experience of the oyster-culting to the artificial cultivation of oysters,* * urists of Europe, they will surely find their ought to be made and continued. A fishery oyster-beds impoverished for having defied the commission, composed of intelligent men, with bioconotic laws.”

P

PANAMA CANAL. The project of con- ond constitutive meeting was held on the 3d of necting the Atlantic and Pacific Oceans, by March. The report then made stated that there means of a tide-level ship-canal across the Isth- were 102,230 shareholders, and that the work mus of Panama, has been carried through its would probably be completed in 1888. Borings preliminary stages during the year, under the and examinations which had been made showed charter granted by the Colombian Government that there would be from 73,000,000 to 75,000,to a French company. The first constitutive 000 cubic metres of earth to be removed. The meeting of the Interoceanic Canal Company, to estimated cost of excavation was 430,000,000 which the grant of the original Internation- francs; construction of weirs and trenches to al Company (see “Annual Cyclopædia,” 1878, convey fresh water to the sea, 46,000,000 title COLOMBIA) had been transferred, was held francs; and the establishment of a dock and in Paris on the 31st of January, M. Ferdinand tide-gates on the Pacific side, 36,000,000 francs de Lesseps presiding. A report was submitted ---making the total cost 512,000,000 francs. by M. de Lesseps, in which the impracticability The contractors, Messrs. Couvreux and Herof the rival Nicaragua scheme was dwelt upon, sent, whose operations were placed in charge of and it was stated that agreement with the M. Blanchet, would begin the great cutting at United States authorities had been reached, Culebra by October, and, before the end of the subject only to the proviso that the neutrality year, work would be begun all along the line. of the canal should be assured. It was further At this meeting the company was unanimously stated that subscriptions had been received for declared to be definitely constituted. 1,209,609 shares of the stock of the company, The engineers and others, who left Paris early of which 994,458 were given in France. The in January, arrived at the Isthmus about the entire capital would be 600,000,000 francs, one middle of February. M. Blanchet followed half of which would be covered by the issue of in April, for the purpose of pushing forward obligations, the other half being distributed in the surveys and examinations of the ground shares of 500 francs each. The report also as rapidly as possible, and preparing for the made known that seventy engineers, superin- work that was to follow. There were already tendents, and doctors had already been sent to seventeen brigades of surveyors in the field, the Isthmus, that steam-engines had been or- and it was announced that the results of their dered, and that arrangements would be made examinations were so favorable that it was for the employment of 8,000 laborers. A sec- believed that the route would be somewhat

* See Annual Cyclopædia," vol. xix (1879), p. 591. shortened, and the time and expense necessary

to carry out the undertaking would be less to the idea of constructing a railroad, with at least than had been estimated. There was more

eight parallel lines, close to the Culebra Mountain, earth and less rock to be removed than had and of shoveling the clay into the Chagres Valley.

But to return to the canal route. From Culebra to been supposed, and the rock was less difficult Panama it will run through solid pyroxenic rock and to deal with. In addition to the final surveys, sandstone tufa, such as you may see on the Bovedas much was accomplished in the way of collect- promenade at Panama. ing machinery and supplies, establishing quar- have as yet not done very much. But the ground has

As regards the actual execution of our plans, we ters for workmen, and getting laborers together. been thoroughly prepared, and we shall now go ahead M. Blanchet succumbed to the climate and the fast. Operations have been begun on the Colon side effects of overwork, and died on the Isthmus of the Isthmus. The excavators are at work, and workin November. M. Roux, who was the chief in shops have been crected for fitting together and recharge of the sounding and testing of the ma- pairing the immense quantity of machinery we have terial to be excavated, returned to Paris in the Couvreux and Hersent are of the most powerful kind. autumn. The following extracts are from a The drags will be capable of removing from eighteen statement made by him to a correspondent on hundred to two thousand cubic metres of subaqueous the 23d of November:

alluvial matter daily. As regards the rock, my idea

was to use the compressed-air perforators employed so I find that from Colon to Tiger Hill the route adopt- successfully at Freggio, the Prato, the Mont Cenis, ed for the canal runs almost entirely through alluvial and the st. Gothard. Nothing is yet definitively soil. Here and there you have volcanio tufa, however. settled about these perforators. We have not pierced From Tiger Hill to San Pablo we have conglomerate through any rock. Up to the present we have been soil, clays, etc. . Between San Pablo and Matachin we busied with preliminary investigations, soundings, come to the alluvial formation of the Chagres, whence hydrographic surveys, etc. for some distance the level of the district traversed is very little above that of the sea-twenty-five metres, or say eighty feet at most. At Matachin the canal will run

M. Roux thought the work could be comthrough the most difficult part of the route. Here we pleted in seven years, but much depended on have to do with solid rock-a most characteristic spec- the health of the workmen. The climate was imen of which is met with close to the cataract of the not so unfavorable as had been reported. YelRio Obispo. The rock is hardest just beyond the cat- low fever was not epidemic on the Isthmus, aract-on the Panama side. Next comes more clayey tufa, overlying the dolorite of the Serro Culebra, the though there were local fevers which were highest point on the canal route. From Matachin to more or less dangerous, but not sufficiently Culebra the cuttings will be extremely deep-in parts prevalent or unavoidable to threaten serious as deep as eighty-seven metres (roughly three hun- embarrassment. There were at that time from dred feet), and hereabout we have been brought face 1,500 to 2,000 workmen in the employ of the to face with a most difficult problem-perhaps the most difficult we have had to deal with-what inclina- company; the majority of them natives-netion should the canal-banks have? This point has groes and Indians. There were also some had my most careful consideration. On a superficial blacks from Jamaica, some Chinese, and a numview of the question it would seem natural to cut ber of Europeans. down in as nearly perpendicular a line as possible. Indeed, many engineers —some of them Americans

About the first of June a majority of the pressed us for a summary settlement of the difficulty stock of the Panama Railroad Company was in that sense. It seemed to me, however, in the high- purchased by the canal company, and arrangeest degree foolish and reckless to give so grave a mat ments were made for absorbing the whole of ter a solution without previous investigation of the it on certain terms, with the consent of the inmost serious kind. A perpendicular or nearly per- dividual holders. 'The nominal amount of the pendicular cutting would, of course, have great advantages, if it could be made, for it is evident that the stock of the railroad company was $7,000,000, slightest additional inclination given to the banks but it had been paying a dividend of 20 per must enormously increase the quantity of rock to be cent, and the shares had been quoted as high as ertheless it was decided that the local formation should $275. The total cost to the canal company of be examined minutely from the summit to the very securing possession of the railway property bed of the projected canal. I feared that the upper was about $20,000,000. strata of rock might be found to rest on a rotten and The prospect of a successful prosecution of unstable foundation. In reply to the suggestions the canal enterprise has raised the question of made me I said, “Let us see whether this rock has a stable basis." 'In the sequel my doubts were shown its relation to the public interests of various to have been reasonable. At about one hundred feet commercial nations. The original contract from the rocky surface I came to tufa, which, though made by the Colombian Government with the originally clayey, had gradually become sandy and Civil International Society of the Interoceanic aquiferous (sables agglutines and aquifères). Now, had Canal, whose rights and privileges have been friends and decided to cut straight banks, the super- transferred to the Interoceanic Canal Company, stratum of rocks, resting on a sandy foundation, must contains the following provision, constituting have fallen into the bed of the canal and blocked it. Article V: “The Government of the republic We shall therefore have to make the banks slope con- declares neutral in all times the ports of both siderably.

The Panama Canal Congress was much exercised extremities of the canal and the waters of the by the numerous and periodic inundations of the Cha- latter from ocean to ocean; and consequently, gres. To oppose them it was suggested that an arti- in case of war between other nations, the tranBcial barrage should be constructed at Gamboa. It sit through the canal will not be interrupted has been proposed that the enormous amount of clay by this motive; the mercantile vessels and at Culebra should be transferred to Gamboa. Being water-tight, it would make an admirable barrier, and the people of all nations of the world will be no masonry would be needed. The engineers incline permitted to enter the said ports without be

« SebelumnyaLanjutkan »