THE FLORIDA COMMERCIAL SPONGES.

By  HUGH M. SMITH. M. D.,
Assistant in Charge of Inquiry respecting F oil-Fishes, United States Fish Commission.

The sponge fishery of the United States presents the interesting antithesis of an industry restricted to a single State and a product perhaps more generally employed and having a wider range of usefulness than any other article yielded by the American fisheries. There is scarcely a civilized habitation in the country in which the sponge is not in almost daily use. Besides its very general employment for toilet purposes, it is utilized in many other ways—in the arts, trades, and professions, and in domestic life—the mention of which would prove tedious.

In this paper it is not expected that much new or original information concerning sponges will be presented. All that is contemplated is to direct attention to certain aspects of the sponge industry, with a view to place it on a sounder basis. The special topics considered are the distribution, form, and peculiarities of the different species; their present and past abundance; the extent and causes of the decrease in the supply, as evidenced by a diminished annual catch; the protection of sponge grounds; the cultivation of sponges on grounds now barren; and the increase of the productiveness of the industry by the introduction of some of the best grades of European sponges. In order to make the discussion of these subjects clearer to the sponge interests, it is desirable to briefly notice the zoological status of sponges and their methods of reproduction and growth. Reference is also made to the sponge legislation of Florida. Illustrations of the leading grades of marketable sponges are presented;, these are based on specimens collected in Florida by the writer.

THE NATURE AND STRUCTURE OF SPONGES.

Although for many years the status of sponges—whether animal or vegetable—was in dispute, the time has long since passed when the right of the sponges to be placed in the animal kingdom was established. Even the propriety of assigning the sponges to a position higher than the lowest animals—the protozoa—is now conceded, and they are put either in a subkingdom of their own (Porifera) or in a subkingdom (Ctelenterata) with the corals, gorgonians, sea-feathers, jelly-fishes, etc.

The sponge in a natural state is a very different-looking object from what we see in commerce. The entire surface is covered with a thin, slimy skin, usually of a dark color, perforated to correspond with the apertures of the canals. The sponge of commerce is in reality only the home or the skeleton of a sponge. The composition of this skeleton varies in the different kinds of sponges, but in the commercial grades it consists of interwoven horny fibers, among and supporting which are spicuhu of siliceous matter in greater or less numbers and having a variety of forms. The fibers consist of a network of fibrils whose softness and elasticity determine the commercial quality of a given sponge. The horny framework is perforated externally by very many minute pores and by a less number of larger openings. These are parts of an interesting double-canal system, an external and an internal, or a centripetal and a centrifugal.

At the smaller openings on the sponge surface, channels begin which lead into dilated spaces (sacs or ampullae); in these, in turn, channels arise which eventually terminate in the large openings (craters or oscula). Through these channels or canals definite currents are constantly maintained which are essential to the existence of the sponge. The currents enter through the small apertures and emerge through the large ones.

The active part of the sponge—that is, the part concerned in nutrition and growth— is a soft, fleshy mass partly filling the meshes and lining the canals. It consists largely of cells having different functions—some concerned in the formation of the framework, some in digestion, some in reproduction. Lining the dilated spaces into which the afferent canals lead are cells surmounted by whip-like processes (cilia); the motion of these processes produces and maintains the water currents, which carry the minute food products to the digestive cells in the same cavities.

Sponges multiply by the union of sexual products, certain cells of the fleshy pulp assuming the character of ova and others that of spermatozoa. Fertilization takes place within the sponge. The fertilized eggs, which should now be called larva?, pass out with the currents of water; and, being provided with cilia, swim actively for a while, like larval oysters. In a comparatively short time, probably in 24 to 48 hours, they settle and become attached to some suitable surface, where they in time develop into mature sponges.

THE FLORIDA COMMERCIAL SPONGES.

The merchantable sponges of the waters of Florida fall under five heads—the sheeps wool or "wool" sponge, the velvet sponge, the grass sponges (two species), the yellow sponge, and the glove sponge. Numerous varieties have been described by naturalists and many grades are recognized by dealers, but all are included in the foregoing designations.

The principal center of the industry is Key West, where more than seven-eighths of the business is carried on. Other places at which sponges are lauded are Apalachicola, St. Marks, and Tarpon Springs. About 100 registered vessels and 200 unregistered vessels and boats are employed in the fishery, which, with their outfit, are worth about $260,000, and are manned by upward of 1,400 fishermen.

Sponges are by far the most important of the fishery products of Florida, representing about one-third of the annual value of the fishing industry.

In the calendar year 1895 the Florida sponge fishery yielded 306,070 pounds of sponges, of which the first value was $386,871. In 1896 the catch, as represented by the purchases of the wholesale buyers, who handled practically the entire output, was 234,111 pounds, having a value of $273,012. In 1897 the product was 331,546 pounds, valued at $281,640.

THE SHEEPSWOOL SPONGE.

The sheepswool is the best sponge found on the shores of the western Atlantic, and for most purposes has no superior anywhere. While the texture is coarser than that of the best Mediterranean sponges, this sponge is more durable—a quality of leading importance for most purposes. Belonging to the same species as the native sheepswool are the well-known eastern horse sponge, Venetian bath sponge, and Gherbis sponge.

The sheepswool sponge is taken on all the important spouging-grounds on the Florida coast. Its distribution may be said to be from Apalachicola on the west coast to Cape Florida on the east coast, although between Charlotte Harbor and Key West but few known grounds exist. The most productive are in the vicinity of Anclote Keys and Rock Island, and from these regions the best quality of sheepswool sponges conies. Between Key West and Cape Florida valuable grounds also exist, those in the vicinity of Matecumbe Key, Knight Key, Bahia Honda, and Biscayne Bay being especially important. This species usually grows on the bare coralline rock which underlies a large part of Florida and is exposed over large areas of the contiguous bottom. On sandy or muddy bottom it is rarely found. It is at present taken in water from 10 to 50 feet deep, but the largest quantities are obtained in depths of 20 to 35 feet. In the early days of the fishery, before the depletion of the grounds had begun, the principal part of the catch was from a depth of less than 12 feet.

With the methods in use in Florida sponges can not be profitably gathered in water more than 50 feet deep, and a question of considerable interest and importance is whether sponges grow in noteworthy quantities at a greater depth. Most spongers think that there are important grounds now beyond their reach, but others think that 50 or 60 feet is the maximum depth at which sponges grow. It is claimed by a few persons that beyond this depth the bottom is not adapted to the growth of sponges, the coralline rock being absent and sand predominating. Definite information on this point is, however, lacking, and a careful survey would be required to settle the matter. The probabilities are that in certain localities there are productive grounds beyond the present limits of operation, as there is nothing in the nature of sponges to prevent their inhabiting deeper water, and it seems improbable that the rocky bottoms should cease to exist beyond 50 feet.

Should future inquiry show the presence of sponge-grounds in water from 50 to 80 feet deep, the discovery of a method of utilizing them would be the first consideration and would prove a great boon to the sponge fishery. Not the least important outcome of such a discovery would be the opportunity afforded the shallower grounds to recuperate by the diversion of the spongers' operations. Attention may be drawn to the advisability of experimenting with an apparatus constructed on the principle of the so called " deep water oyster-tongs," by means of which oyster-beds beyond the reach of ordinary tongs become readily accessible.

The tongs in question, of which there are several types, consist essentially of two curved iron bars, riveted together near the middle to permit free motion. These arc attached on one extremity to the teeth and cradles, and on the other to the ropes by means of which the apparatus is lowered and raised. Beneath the crossing -point of the two arms a weight is suspended. To the upper bar of one side an iron link or loop is attached by means of a staple, and on the lower bar, just below the link, is a small iron peg or stud over which the link fits when the teeth are separated to their widest extent. When oystering begins, the arms are locked by means of the loop and peg and the tongs lowered to the bottom. By suddenly dropping the tongs from the height of a few feet from the bottom the loop slips off the pin, by virtue of the weight referred to, and the teeth will then approach each other when the ropes are hauled taut. The weight and the loop and peg may, however, if desired, be dispensed with by attaching a line to the crossing-point of the two arms and placing weights at the upper ends of the latter, the tongs being lowered by means of the middle line and kept open by the weights mentioned.

The extreme simplicity of this apparatus is a great recommendation for its use in the oyster fishery, and suggests its employment in the sponge fishery. It is open to the objection of being somewhat heavier than the ordinary oyster-tongs, and in deep water a small windlass must bo attached to the mast or elsewhere on the boat, by which it can be raised and lowered. The cost, complete, is about $15. If the principle embodied in this apparatus is found to be adapted to the sponge fishery a modification in the line of lightness and cheapness could doubtless be made. The number of teeth and the carrying capacity of the tongs required in the oyster fishery might be reduced and the apparatus made to consist practically of two opposing hooks, such as are now used in the sponge fishery.

The sheepswool is probably the most abundant of the Florida sponges, although it is not relatively so abundant as the catch of it and other species would indicate, owing to the fact that its greater value makes it more eagerly sought.

The decrease in the abundance of this species has been marked in many places. In the vicinity of Auclote Keys the grounds in 10 to 1U feet of water were exhausted before the civil war; but during the war the sponge-beds had a chance to recuperate, and later afforded some good fishing. They were very soon depleted, however, and have not since borne sponges in any noteworthy quantities. This is the general history of the "bay grounds." Deeper and deeper bottom has had to be resorted to in order to make the fishery profitable, until now some fishing is done in water as deep as 50 feet. Occasionally good fares are taken on the inshore and key grounds. The latter, in depths of 10 to 20 feet, seem to recuperate more rapidly than the bay grounds, and produce excellent crops some seasons; but they have in general shown the same depletion as other grounds, and the spongers have to work over a larger area and more assiduously than was necessary a few years ago. Even the deepest grounds now frequented are showing the effects of overfishing, and would doubtless soon prove nonproductive of marketable sponges if the weather and water were always favorable to the spongers, the preservation of the beds largely depending on the prevalence of storms or turbid water during some seasons or parts of seasons.

The sheepswool is believed by many observers to grow the most rapidly of any of the sponges, but information on this point is not as complete or accurate as might be desired. Some experiments performed and observations made by gentlemen of Key West lead them to believe that this species may, under favorable conditions, grow from the beginning to one tenth of a pound weight in six months. The opinion that this sponge will grow from the spat to good commercial size in one year is practically unanimous and seems to be verified by the sponging operations. The spongers all testify that grounds which were thoroughly fished out one year are found to yield large numbers of commercial sponges twelve months thereafter.

The catch of the sheepswool in 1895 was fifteen times and in 1897 six times as valuable as that of all other species combined, and is thus sufficiently important to give prominence to the sponge industry, even if no other kinds were taken. The average prices per pound brought by sheepswool sponges were $1.57 in 1805, $1.66 in 1896, and $1.53 in 1897.

Of late, owing to a diminished supply, the relative catch of sheepswool sponges has been decreasing, cheaper varieties entering more largely into the receipts. In 1895 the percentage of sheepswool sponges in the total catch was 76; in 1896 it fell to 64, and in 1897 was only 47.

THE VELVET SPONGE.

This is an uncommon form, with a very limited distribution. Along the west coast of Florida it is rarely found, the yield coming almost entirely from certain grounds among the keys. It resembles the sheepswool in general structure, but has a smoother surface and finer fibers. The characteristic feature is the presence of soft protruding cushions, whence the name. It is also known as the boat sponge. Its shape is very irregular. Its average size is 7 or 8 inches in diameter, but the diameter of some is a foot or a little over. Its principal source of supply is the region adjacent to the Matecumbe Keys, where it is taken on coral bottom in water from 15 to 20 feet deep. The grounds have undergone serious depletion, and smaller cargoes are landed each year. Velvet sponges are taken in smaller quantities than any other Florida sponges. In 1897 many dealers did not handle any, and the receipts in recent years have never exceeded a few thousand pounds per annum. The usual price paid by dealers is 50 cents a pound.

THE GRASS SPONGES.

There are at. least two species comprehended under the trade name of grass sponge, and the individual variations are numerous. One species (called NIiongia tjrantinea by Hyatt) has a coarse, open structure, with deep furrows on the sides, in which the afferent channels always begin. The general shape is that of a truncated cone, with the larger openings always on top. The other grass sponge (Kiispongin c'/xina cerebriformiif) resembles one form of the yellow sponge, but differs in having its surface marked by parallel longitudinal ridges surmounted by two or three lines of tufts. In the depressions between the ridges the large efferent canals open, their orifices being in rows. Many forms of this species exist. The cup shape predominates.