.^ tb- <&■ APR 15 1310 AMERICAN FISHES IN ITALY. ■*. By GUISEPPE BESANA, President Lariana Section, Lombardy Society oj Fislieries and Aquicullure. J* [Translated from the German.] REARING IN ARTIFICIAL PONDS. In the small ponds of the Piseicoltura Borghi at Varano-Borghi, opened in 1907, were produced at first mostly fry and yearling fishes for stocking purposes. But as the plants were without results, the ponds were increased in number and the rearing of table fishes was undertaken, including attempts to cultivate American trouts and salmon, namely, Salmo irideus, Oncorhynchus tschawytscha, and Salvelinus fontinalis. Experiments were made also with Salmo clarkii, crossing it with the rainbow trout. Of these fishes, at the present time only the rainbow trout is being culti- vated. The quinnat grew extraordinarily fast during the first year and without losses, reaching a size for table use during that one year; but the flesh was not yet firm nor of good flavor. The growth was still good during the second year, but in the third year there remained but very few of the fish, and they were thin and for the most part died during the period of spawning. The quinnat presented another disadvantage during the second year, being so delicate that when fished out to be transferred to other ponds, in spite of the great care taken, a great number of them died. The brook trout grew very well during the first year, markedly less during the second year, still less during the third, while the mortality continually increased. Compared with the European sal- monoids the best results were obtained with the rainbow trout. In the second summer these trout reached the size of table fishes, weighing 150 to 200 grams, and the flesh had a good flavor. They endure transportation well, and readily take artificial food. We know of no other salmonoids so well adapted to culture in ponds. The few experiments in crossing the irideus with the clarkii trout did not encourge further effort, as the growth of the hybrid is far inferior to that of irideus. 949 950 BULLETIN OF THE BUREAU OF FISHERIES. PLANTS IN LAKE MANATE. The area of this lake is 240 hectares; greatest depth, 37 meters; plankton abundant; vegetation scant; maximum temperature of water, 8° C. at the bottom, 24 C. at the surface; minimum temperature, 8° C. at the bottom, o° C. at the surface. The native fishes of this lake are, in the order of their abundance, river perch, tench, roach, pike, bleak, eel, and burbot. Tables 1, 11, hi, and iv show the plants of the introduced fishes and the catch. Table V gives the catch for 1907. Table I. — Rainbow Trout (Salmo irideus). 1S97 1898 1899 1899 1900 1901 1901 1902 1903 1904 Size or age of fish planted. Fishes 2 years old Small fry Yearlings Fry 2 months old Fry 2 months old Yearlings Fishes weighing 400 grams each Fry 2 months old Small fry Small fry Total Number planted. 800 4. 130 8.6:8 676 1, 400 300 21 4.500 10. 000 10. 000 Number caught. Weight of catch. Kilograms 9. 800 Table II. — Brook Trout (Salvelinus fontinalis). 1903 j 903 1903 1904 1905 Size or age of fish planted. Fry 2 months old Yearlings Fish weighing 200 grams each Small fry Yearlings Total Number planted 2 . 240 80 150 2. 500 518 5.488 Number caught. Weight of catch. Kilograms. Table III. — Black Bass (Micropterus salmoides). Size or age of fish planted. Number planted. Number caught. Weight of catch. 1897- 1897- 1897- 1899- 1901. 1902. 1903- 1904- 190s- 1906. 1907- Yearlings Fish 2 years old. Fish 3 years old- 500 86 6 30 76 226 163 372 343 803 241 .254 Kilograms . 7» 217 196. 284 246 368 147 AMERICAN FISHES IN ITALY. Table IV. — Sunpish (Lepomis auritus). 951 Year. Number of fish planted. A verage weight when planted. Weight of catch. 1901 . __ __ _ _ _ __ 140 66 91 Gravis. 30 45 50 Kilograms . 1 90 1 _ _ _ _____ . 164. 60 249. 20 300. 10 302. 70 Total _ ___ 297 1. i37 40 Table V. — Total Catch in Lake Manate in 1907. Species. Number. Weight. 618 Kilograms. 706. 70 562- 80 107 24 53 14. 70 46.50 302. 70 302. 70 241 4 Total... _ _ _ - . 2, 107. 20 Failures were noticeable with the salmonoids. I must add, however, that I have had similarly negative results with European salmonoids. It was only in the beginning of this year that there were caught 100 Coregonus marcene, weighing from 0.50 to 2 kilograms. Fry of this species had been introduced, and a large individual was seen only here and there. No fry had been planted in the lake for four years, and the smaller fishes which were caught, weighing 800 grams, must, have been bred from fishes that had spawned in the lake. The sunfish did not increase greatly in this lake; the catches are insignifi- cant and have never exceeded 300 kilograms yearly, i. e., somewhat over 1 kilogram per hectare. I had built great hope on the black bass. Young Micropterus were seen everywhere during the first years. The first catch was made only four years after their introduction, and it increased to 368 kilograms. During the last year, however, it fell to one-half of this quantity, and the present year will show still poorer results. When the black bass was introduced there were quantities of bleak in the lake, and this fish was not caught at all. At the present time it has entirely disappeared. Lake Manate yields at present, as formerly, 3,000 to 5,000 kilograms of fish yearly. No benefit was derived from the introduction of new species of fishes, 952 BULLETIN OF THE BUREAU OF FISHERIES. but perhaps even some disadvantage. Micropterus, which bring a higher price, have disappeared, as have also the river perch and the pike, probably on account of a lack of small fishes for food. The tench and the roach (Lcuciscus erythro- phtalmus) are the only ones that remain. How to provide new food is the present difficult problem, which, after the failure with the sunfish, will scarcely find easy solution with present experience. PLANTS IN LAKE VARANO. Area of this lake, 360 hectares; greatest depth, 7 meters; much plankton, very rich vegetation; maximum temperature of the water, 24 C. at the surface, 24 C. at the bottom; minimum temperature, o° C. at the surface, 6° C. at the bottom. The species of fish contained in the lake are, in the order of their abundance, sunfish, river perch, tench, bleak, black bass, eel, zander, mirror carp, and pike. The sunfish and black bass, also the zander and the carp, were introduced in this lake. The results obtained with the American fishes here are marvelous, especially with the sunfish, as two other lakes communicating with Lake Varano are over- stocked with sunfish. It is scarcely possible to notice any effect on the other kinds of fishes, except that the pike has grown scarcer and the bleak has disappeared. The river perch is much fatter and grows much more rapidly than before. The plants of introduced fishes, together with subsequent catches, are shown in tables vi and vii. The yearly output of fish of all kinds, amounting, formerly to 170 tons, has increased to 300 and more tons. Table vm gives the total catch for 1907, which is exceedingly good, amounting to almost 90 kilograms per hectare. . Table VI. — Sunfish (Lepomis aukitus). [Eiyhty-three 3-year old brood fishes introduced in 19C0.] 1901 . 1902. 1903- 1904- 1905- 1906. Iy07_ Total. Weight of catch. Kilograms 682 1. 919 5. 845 S.958 7.456 5.99o 12. 811 40.665.3 AMERICAN FISHES IN ITALY. Table VII. — Black Bass (Micropterus salmoides). 953 Fish introduced. Number caught. Weight of catch. Year. Number. Size or age. Average weight. 8 I . ooo 21 6 Grams. 560 Kilograms. IOOO 860 500 859 3. 193 2. 183 8.941 5.896 2. 204. 90 2. 987. 20 21. 872 Table VIII. — Total Catch in Lake Varano in 1907. Species. Tench (Tinea vulgaris) River perch (Perca fluviatilis) Small eels (Anguilla vulgaris) Large eels (Anguilla vulgaris) Pike (Esox lucius) Bleak ( Alburnus alborella) Sunfish ( Lepomis auritus) Black bass (Micropterus salmoides). Carp (Cyprinus carpio) Zander (Lucioperca sandra) Total . Number. 1 . 066 894 224 5.896 52 219 Weight. Kilograms. 3.634.70 7. 568. 10 280. 50 4S7-30 232. 10 2. 626. 60 12, 81 1 . 40 2.345 70 280. 30 407. 70 30,644. 40 I was criticised for introducing the sunfish, but I believe that I do not deserve it. The sunfish is of much better flavor than the ordinary bleak. Delicious steaks can be cut out of the larger of them, and the fish bring a good price where better known. They are also a very good food for the carnivorous fishes in the lake. They increase in an extraordinary manner in shallow lakes and must be fished out diligently. They do not reach any importance in deeper lakes and in consequence can not have any effect. In lakes where there are no salmonoids the sunfish should be an excellent item of popular, food. The average weight of the fish caught is 100 grams, which is reached in three years, but we have caught individuals weighing 400 grams. Another advantage is that except when the lake is frozen it is always possible to catch more or less sunfish, a thing which is of great importance to the fisherman. The long spawning season, lasting from May until the middle of August, offers the advantage that, as the sunfish do not grow during the winter, there is present through almost the entire year a quantity of small fishes to constitute a food for the predator}' species. If the sunfish now and then eats other small fry, it does not consume dangerously great quantities. That it does not eat spawn is well established. The fish should be of great value in Italy in swampy waters, where it thrives "g" 002 "861 299 * 954 BULLETIN OF THE BUREAU OF FISHERIES. very well and can stand great heat and great cold. While Lake Manate, which is of far greater depth, produced only a little more than i kilogram per hectare, the shallow Lake Varano with its swampy bottom produced 35 kilograms of sunfish per hectare during the past year. The black bass also flourished in this lake (table vn) , yielding somewhat less than 10 kilograms per hectare. The fishing is very irregular and uncertain, however, some 100 kilograms being caught one day, while on the next not one fish maybe found. The black bass can be transported safely alive. Its flesh is boneless and very palatable, but its plump shape and big head make its sale difficult. There is much around the head that can be eaten, but most people prefer the zander. The growth of the black bass is markedly greater than that of the river perch. While the latter seldom reaches 1 kilogram and this in some eight or nine years, the black bass reaches this weight in three years. It increased in number considerably during the first years, but later, when there were many large individuals, these ate up many of the smaller of their species. It has no effect whatever on the other fishes in the lake, except Alburnus alborella, which it has eaten up entirely. I certainly prefer the zander, but it can not be introduced into all waters, while the black bass will thrive anywhere. I have also introduced the black bass in small lakes with great success and at a small cost. In order to make this success lasting, however, it is necessary to introduce the sunfish at the same time. The small bleak is soon eaten up by the black bass, the sunfish alone, on account of its enormously prolific propagation, being able to withstand and keep ahead of this terrible devourer. On account of the defective organization on the part of our government in respect to fisheries, it is impossible for me to report on the introduction of rainbow trout in public waters, or on catfish, black bass, and sunfish in other lakes. It may be seen, however, from the above reports, that great advantages may be reaped from the introduction of these and other American fishes. LIBRARY OF CONGRESS mill i! nun 002 861 299 He LIBRARY OF CONGRESS 002 861 299 01 Hollinger Corp. P H8.5