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Bulletin of the United States Fish Commission 1898 Contributions from the Biological Laboratory of the U. S. Fish Commission, Woods Hole, Massachusetts. THE REAPPEARANCE OF THE TILEFISH. PART 1...
TO PART TWO
During the past summer the investigations of the United States Fish Commission have brought to light the facts that the tilefish (Lopholatilus chameleonticeps), once supposed to be extinct, occurs in great numbers off the southern coast of New England, and that its capture requires only the ordinary apparatus used in cod and haddock fishing. This fish possesses excellent food qualities and its reappearance may result in the development of an industry of considerable importance. Its history is of scientific interest, since it furnishes evidence that life on the sea bottom is subject to periodic modification, and that a species almost annihilated may become quickly reestablished. In May, 1879, Captain Kirby, of Gloucester, in command of the schooner William V. Hutchins, while searching for cod and hake almost directly south of Nantucket, caught great numbers of a "strange and handsomely colored fish." The first catch, of nearly 2,000 pounds, was made in water varying from 80 to 120 fathoms in depth, at latitude 40° 04' N., longitude 7U° 23' W. Four trawls were used, each about a mile in length, and bearing 1,000 hooks. Nearly all of these fish were thrown overboard, but a few were kept and cooked. Captain Kirby stated that they were the finest fish he had ever eaten, and he determined to save and salt all that he might catch. The trawls were set the same day in latitude 40° 041 N., longitude 70° 17' W., and again in latitude 40° 00' N., longitude 70° 04' W. Both sets yielded about 2,000 pounds of dressed fish, which, on being landed in Gloucester, were sold to Messrs. Friend & Son, who disposed of them in various ways. Captain Kirby sent one of the fish to the United States National Museum, where it was examined by Messrs. Goode & Beau, and described (Proceedings U.S. Nat. Mus., vol. II, pp. 205-2O8) as a new genus and species (Lopholatilus chameleonticeps). Recently it has been assigned by Jordan & Evermann to the family Malacanthidae, a group of fishes of somewhat obscure relationship, found in temperate and tropical seas. In July of the same year Captain Dempsey, also of Gloucester, caught 9 tilefish while fishing for cod in a locality 50 miles south by east of No Man's Land, in 75 fathoms of water.
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Professor Baird took great interest in the discovery of this new fish. Its fine flavor and attractive appearance indicated excellent marketable qualities, and its great abundance promised to be a profitable source of income to offshore fishermen. The Fish Hawk took 3 specimens on the 13th of September, 1880, in 126 fathoms, latitude 39° 57' N., longitude 70° 56' W., and so anxious was Professor Baird to gain additional information that he chartered the fishing smack Mary Potter, of Noanh, in which Mr. Vinal Edwards left Newport for the tilefish grounds on the 29th of September. A trawl line of 400 hooks, baited with menhaden, was set in 127 fathoms, but only a swordfish and two skates were caught. Threatening weather then drove the vessel back to port. On August 9, 1881, trawl lines were set from the Fish Hawk in 131 fathoms, latitude 40° O2' N., longitude 71° 12' W., and 8 tilefish, weighing 147 pounds, were taken. On August 23, in latitude 40° 03' N., longitude 70° 31' W., 73 fish, weighing 540 pounds, were taken. The trawl line was set again on September 21 at a point farther to the eastward, latitude 39° 58' N., longitude 70° 06' W., in water of 113 fathoms, but no fish were taken. In March and April, 1882, vessels entering New York and other Atlantic ports reported that they had passed through countless numbers of dead fish while crossing the northern edge of the Gulf Stream. Investigation proved that these were tilefish, and that they appeared on the surface of the water over an area of 170 miles in length and 25 miles in width. A conservative estimate, made by Capt. J. W. Collins (Fish Commission Report for 1882), who has given a detailed history of the tilefish up to the time of this mortality, placed their number at upwards of 1,438,720,000. Allowing 10 pounds to each fish, he has estimated that there would be 288 pounds of fish for every man, woman, and child in the United States. In September, 1882, Professor Baird chartered the Josie Reeves, and sent her to the tilefish grounds, that he might ascertain to what extent the species had been depleted, but the vessel returned without having found a single individual. This seemingly unprecedented destruction of marine life was extensively commented upon both by newspapers and scientific journals, and in the Report of the U.S. National Museum for 1889 the tilefish was placed, provisionally, in a list of extinct animals. The scientific work that finally led to the rediscovery of the animal really began in the summer of 1880, when the completion and equipment of the Fish Hawk made it possible to enter upon lines of investigation which before were out of the question. This vessel has added materially to the practical efficiency of the Commission, and its frequent employment by men of science has greatly increased our knowledge of oceanic life. In November, 1880, Professor Merrill published his memorable "Notice of the remarkable marine fauna occupying the outer banks of the southern coast of New England" (Am. Jour. Sci., Nov. 1880, p. 390), in which he gave the scientific results of three excursions made by the Fish Hawk . On these excursions the dredge was used 23 times, and an enormous number of deep-sea animals were taken. Among these were 130 species of mollusks, 26 echinoderms, 43 crustacea, and 16 fish new to the southern coast of New England, and many of these animals were also new to science. During the following summer, 1881, seven excursions were made to the Gulf Stream, where, besides the work done with the line trawl already mentioned, the ------------------- Bulletin of the United States Fish Commission 1898 Page 323 dredge was used 47 times. It is fortunate that these investigations were made in 1880 and 1881, since they furnished definite data respecting the physical and biological conditions of a tract of the sea bottom which in the spring of 1882 became the scene of widespread devastation. While Captain Collins was collecting his data, the Fish Hawk, which had taken a few tilefish in 1880, and had found them very numerous in 1881, was continuing her deep-sea explorations under the direction of Professor Verrill. During August, September, and October, 1882, five trips were made to the tilefish grounds, and the dredge was lowered 46 times. The definite information relative to the life on the sea bottom, which Professor Verrill had been able to secure during the summers of 1880 and 1881, now became of great value, since it enabled him to report on the general faunistic changes which had affected this area, to measure the extent of the destruction of oceanic life, and to give an intelligent reason therefor. In the report for 1882, he writes: "One of the most peculiar facts connected with our dredging this season (1882) was the scarcity or absence of many of the species, especially crustacea, that were taken in the two previous years, in essentially the same localities and depths, in vast numbers, several thousand at a time." In another article (Physical characters of the portion of the continental border beneath the Gulf Stream, explored by the Fish Hawk, 1880 to 1882), Professor Verrill describes the rapid incline of the sea bottom beyond the 100-fathom line, "usually as steep as the side of a great mountain chain, and about as high as Mount Washington, New Hampshire." He further writes: "The bottom along the upper half of this slope and the outermost portion of the adjacent plateau, in 65 to 150 fathoms, and sometimes to 200 fathoms or more, is bathed by the waters of the Gulf Stream. Consequently the temperature of the bottom water along this belt is decidedly higher than it is along the shallower part of the plateau near the shore, in 25 to 60 fathoms. We may therefore call the upper part of the slope, in about 85 to 150 fathoms, the "warm belt." (Report U.S. Fish Commission for 1882, p. 279.) It was along this warm belt that many animals characteristic of tropical or subtropical fauna were dredged in 1880 and 1881, and Professor Verrill states: In fact, this belt is occupied by a northern continuation of the southern or West Indian Gulf Stream fauna...that could not exist there if the Gulf Stream did not flow along this area at the bottom, both in winter and summer." The tilefish, whose relatives are known to be tropical, doubtless belongs to this warm-water fauna, and the destruction of 1882 was explained by Professor Verrill when he wrote, in October of that year: "It is probable, therefore, that the finding of vast numbers of dead tilefish floating at the surface in this region last winter was connected with a wholesale destruction of the life at the bottom, along the shallower part of this belt (in 70 to 150 fathoms), where the southern forms of life and higher temperature (47° to 52°) are found. This great destruction of life was probably caused by a very severe storm that occurred in the region at that time, which, by agitating the bottom water, forced outward the very cold water that even in summer occupies the wide area of shallower sea in less than 60 fathoms along the coast, and thus caused a sudden lowering of the temperature along this narrow warm zone, where the tilefish and the crustacea referred to were formerly found. The warm belt is here narrow, even in summer, and is not only bordered on its inner edge, but is also underlaid in deeper water by much colder water. In fact, the bottom water inshore is probably below 32° F. in winter where the depth is 20 to 40 fathoms. In August this year (1882) we found the temperature 37° F, south of Cape Cod, in 55 to 60 fathoms. It is evident, therefore, that even a moderate agitation and mixing up of the warm and cold water might in winter reduce the temperature so much as to practically obliterate the warm belt at the bottom. But a severe storm, such as the one --------------------- Bulletin of the United States Fish Commission 1898 Page 324 "referred to, might even cause such a variation in the position and direction of the tidal and other currents as to cause a direct flow of the cold inshore waters to temporarily occupy the warm area, pushing farther outward toward the Gulf-Stream water. The result would in either case be a sudden and great reduction of temperature, perhaps as much as 15 to 20 degrees. This could not fail to be very destructive to such southern species as find here nearly their extreme northern limits. It is probable, however, that these southern species, including the tilefish, were not thus destroyed farther south. Therefore it is probable that in a few years they will again occupy these grounds by migrating northward, even if there be not enough left here to replenish their races." -(Report of the United States Fish Commission, 1882, p. 279.) These quotations are here inserted because they are based on facts ascertained by those interested in the scientific work of the Commission and because they explain adequately the cause of the mortality, ascribing it to climatic changes. (*) In 1883 the Fish Hawk made but one excursion to the Gulf Stream, and even then did not reach the edge of the "warm belt," the deepest water in which the dredge was cast being only 62 fathoms. The Albatross worked on the ground, how ever, and cast the dredge at least 20 times over the area known to have been occupied previously by the tilefish, Since 1883, up to the present time (January, 1899), the Fish Hawk has not again attempted to explore this portion of the sea bottom. In 1884 the Albatross made a most careful survey of the "tilefish grounds" and the tracts of deeper and shallower water bounding the same. The dredge was lowered 76 times, and although material of great scientific interest was secured, no trace of the tilefish was found. In 1885 the examinations of the sea bottom in this locality was continued, and the dredge was lowered from the Albatross 38 times. In 1886 the Albatross lowered the dredge 14 times, but no tilefish were found. It is worthy of note that the first cruise made by the Fish Commission schooner Grampus was to the tilefish grounds. The vessel left Newport on August 14, 1886 and set trawls in 96 fathoms (latitude 39° 59' N.; longitude 70° 15' W.), and although trawls and hand lines were repeatedly used until August 31 the ground was so barren that only a few hake were taken. The stomachs of these fish showed a scarcity of food suitable for the Lopholatilus, and Captain Collins concluded that-- "It is safe to say that the large number of sets made with the trawl line on this occasion, together with the trials made with hand lines, clearly demonstrate the fact that if the tilefish has not become absolutely extinct in this region it is certainly so rare that the chances of obtaining it are limited." In 1887 the Albatross made three unsuccessful efforts to find the tilefish, and in November left the Atlantic waters and sailed to the Pacific, where she has remained. In 1888 no attempt was made to visit the tilefish ground. In 1889 Prof. William Libbey, jr., began a series of temperature and specific gravity observations off the shore of southern New England, which extended directly over this interesting tract. These observations were made for the purpose of: "establishing some connection between the changes in temperature in the waters and the migrations of the fish which inhabit them." The Grampus was placed at the disposal of Professor Libbey, and an account of his work for the summer of 1889 will be found Footnote * Professor Libbey, in a paper read before the Geographical Congress in 1895, claims that the effect of any single storm is largely superficial, and that it takes the resultant of several years of storms permanently in one direction or the other to produce such effects in deep water. Professor Libbey ascribes the disappearance of the fish to conditions just the reverse of those mentioned by Professor Verrill, namely, the cold body of water on the continental platform was allowed to advance over the area upon the edge of the Continental plateau by at retrogression of the warm waters of the Gulf Stream produced by the exact opposite of the conditions which caused its advance toward the same edge. (End of Footnote) ---------------------------------------------------- Bulletin of the United States Fish Commission 1898 Page 325 in the U. S. Fish Commission Bulletin, vol. IX. This account contains a record of over 1,600 temperature observations, and the general results were of such importance that Commissioner McDonald continued the work during the summer of 1890, at which time the United States Coast Survey steamer Blake was detailed to act in cooperation with the Grampus. During the summer of 1891 the Grampus was placed again at the disposal of Professor Libbey, and the work was continued along the same lines as during the two previous years. Unfortunately, the results of these investigations, perhaps the most complete ever conducted over a tract of the ocean of equal extent, have never been published, although they yielded extremely important data relative to the physical changes affecting the sea and the sea bottom. Professor Libbey found that a comparison of the temperature records as shown by the temperature cross-sections constructed upon the basis of the observations made in this body of water for the three years 1889, 1890, and 1891, demonstrated that there had been a progressive movement of the warm water, of 50° temperature, toward the shore. In a communication addressed to Commissioner McDonald in 1892, Professor Libbey wrote: "In 1889 the lower portion of the curve did not touch the edge of the continental platform at any point within the area we were studying. In 1890 this portion of the curve touched the continental edge both at Block Island and off Nantucket Island in the latter part of the season; and in 1891, as has been said, it touched along the whole edge of this portion of the platform during the greater part of the summer. The change which was thus produced in the temperature at the bottom along this edge of the continental platform was in the neighborhood of 10°, an item of considerable importance. (Report LT, S. Fish Commission, 1893, p. 34.) Professor Libbey, in a conference with Commissioner McDonald, showed that if the movement of the warm band toward the shore continued during the summer of 1892, the whole of the continental edge, or that part of it upon which the tilefish had once flourished, would present environmental conditions favorable to the return of the fish. The importance of these presentations was recognized by Commissioner McDonald, and though other work had been laid out for the Grampus, she was ordered to prepare for further explorations of the Gulf Stream and the bottom fauna off the southern New England coast. Professor Libbey writes: "In July the Commissioner and myself went out in the schooner Grampus, south of Martha's Vineyard, to the area which seemed to promise a reward for our labors. We found the temperature conditions right, set the cod trawls, and caught the tilefish. During the remaining portion of the summer I spent considerable time tracing out the limits of the area over which the temperature of 50° and above could be found, using the trawl lines at the same time to ascertain if the fish were there. We found them all the way to the Delaware capes, and were satisfied that, though they were not numerous, they had taken advantage of the changed conditions to occupy the area." It is thus seen that whereas Professor Verrill in 1882 had given reasons for the disappearance of the fish, and had stated that, "It is probable that in a few years they will occupy these grounds by migrating northward, even if there be not enough left here to replenish their race," and although an indiscriminate search of ten years had failed to find any trace of the lost fish, the results of Professor Libbey's temperature investigations enabled him to show that the physical conditions of the sea bottom were variable, to prove that there was a definite movement of warm water toward the area earlier occupied by the tilefish, and to predict that if this movement continued the tilefish would be found again in its old habitat. -------------------------------------------------------- |