Part 2 (2/2)
It had, however, been found that the old location had serious defects.
The inclosure was costly to maintain, and the recapture of the fish involved a great deal of labor and trouble. The water supplied to the hatchery was liable in seasons of little rain to be totally unfit, causing a premature weakening of the sh.e.l.l and very serious losses in transportation. After a careful search through the neighboring country it was found that the most promising site for an inclosure was in Dead Brook, near the village of Orland (though within the limits of the town of Bucksport), and for a hatchery no location was equal to Craigs Pond Brook, the spot where the original experiments were tried in 1871. The only serious drawback was the separation of the two by a distance of some 2 miles, which could not offset the positive advantage of the hatchery site. Accordingly the necessary leases were negotiated, an inclosure made in Dead Brook, and a stock of breeding salmon placed therein in June, 1879. Since then the work has been continued without interruption.
It is still found most convenient to obtain the stock of breeding salmon, as in the early years of the enterprise, from about a dozen weirs in the Pen.o.bscot River along the sh.o.r.es of the island of Verona.
The fishermen are provided with dip-nets or bags with which to capture the fish in their weirs, with tanks or cars in which to transport them to the collecting headquarters, whither they are brought immediately after capturing, about low water.
The collection is in the hands of a fisherman of experience, who receives the salmon as they are brought in, counts and examines them, adjudges their weight, and dispatches them in cars to the inclosure at Dead Brook. The cars are made out of the common fis.h.i.+ng boats of the district, called dories, by providing them with grated openings, to allow of a free circulation of water in transit, and covering them with netting above to prevent the fish from escaping over the sides. The car is ballasted so that it will be mostly submerged. Ten to fifteen salmon are placed in a single car, and from one to four cars are taken in tow by a boat with two to four oarsmen.
From the collecting headquarters to Orland village, a distance of about 5 miles, the route is in brackish water, and the tow is favored by the flood tide. At Orland is a dam which is surmounted by means of a lock, and thence, two miles further to Dead Brook, the route is through the tide less fresh water of Narramissic River. The sudden change from salt to fresh water does not appear to trouble the fish except when the weather is very hot and the fresh water is much the warmest. The cars are towed directly into the inclosure, where the fish are at once liberated.
The inclosure is formed by placing two substantial barriers of woodwork across the stream 2,200 feet apart. The lower barrier is provided with gates which swing open to admit boats. Within the inclosure the water is from 3 to 8 feet deep, the current very gentle, the bottom partly muddy, partly gravelly, supporting a dense growth of aquatic vegetation. The brook has two clean lakes at its source, and its water is purer than that of ordinary brooks.
The collection of salmon usually continues from the first ten days of June until the beginning of July. During the early weeks of their imprisonment the salmon are extremely active, swimming about and leaping often into the air. After that they become very quiet, lying in the deepest holes and rarely showing themselves. Early in October they begin to renew their activity, evidently excited by the reproductive functions. Preparations are now made for catching them by constructing traps at the upper barrier. If the brook is in ordinary volume, these means suffice to take nearly all, but a few linger in the deeper pools and must be swept out with seines. About October 25 the taking of sp.a.w.n begins. After that date the fish are almost always ripe when they first come to hand, and in three weeks the work of sp.a.w.ning is substantially finished.
Although the salmon are taken from the fisherman without any attempt to distinguish between males and females, it is always found at the sp.a.w.ning season that the females are in excess, the average of four seasons being about 34 males to 66 females. This is a favorable circ.u.mstance, since the milt of a single male is fully equal to the impregnation of the ova of many females.
The experiment has several times been tried of marking the salmon after sp.a.w.ning and watching for their return in after years. After some experiments, the mode finally fixed upon as best was to attach a light platinum tag to the rear margin of the dorsal fin by means of a fine platinum wire. The tags were rolled very thin, cut about half an inch long and stamped with a steel die. The fish marked were dis missed in the month of November. Every time it was tried a considerable number of them was caught the ensuing spring, but with no essential change in their condition, indicating that they had not meanwhile visited their sp.a.w.ning grounds. In no case was a specimen caught in improved condition during the first season succeeding the marking.
But the following year, in May and June, a few of them were taken in prime condition--none otherwise--and it several times occurred that female salmon were a second time committed to the inclosure and yielded a second litter of eggs. The growth of the salmon during their absence had been very considerable, there being always an increase in length and a gain of twenty-five to forty per cent. in weight. The conclusion seems unavoidable that the adult salmon do not enter the Pen.o.bscot for sp.a.w.ning oftener than once in two years.
The method of impregnation employed has always been an imitation of the Russian method introduced into America in 1871. The eggs are first expressed into tin pans, milt is pressed upon them, and after they are thoroughly mixed together, water is added. The result has been excellent, the percentage of impregnated eggs rarely falling so low as 95.
After impregnation the eggs are transferred to the hatchery at Craig's Pond Brook, where they are developed, resting upon wire-cloth trays in wooden troughs, placed in tiers ten trays deep, to economize s.p.a.ce, and at the same time secure a free horizontal circulation of water.
The hatchery is fitted up in the bas.e.m.e.nt of an old mill, of which entire control has been obtained. The brook is one of exceptional purity, and a steep descent within a few feet of the hatchery enables us to secure at pleasure a fall of 50 feet or less. The brook formerly received the overflow of some copious springs within a few hundred feet of the hatchery, which so affected the temperature of the water that the eggs were brought to the s.h.i.+pping point early in December, an inconvenient date. This has been remedied by building a cement aqueduct 1,600 feet long, to a point on the brook above all the springs, which brings in a supply of very cold water.
The s.h.i.+pment of eggs is made in January, February, and March, when they are sent by express, packed in bog-moss, all over the northern States, with entire safety, even in the coldest weather.
In the following statement is embraced a general summary of the results of each season's work:
[IMAGE orlandeggs.png in html file--table in text file]
Salmon Females Eggs Eggs Year bought sp.a.w.ned obtained distrib'd ---- ------ ------- -------- --------- 1871-72 111 11 72,071 70,500 1872-73 692 225 1,560,000 1,241,800 1873-74 650 279 2,452,638 2,291,175 1874-75 601 343 3,106,479 2,842,977 1875-76 460 237 2,020,000 1,825,000 1879-80 264 19 211,692 200,500 1880-81 522 227 1,930,561 1,841,500 1881-82 513 232 2,690,500 2,611,500 1882-83 560 256 2,075,000 2,000,000 ----- ----- ---------- ---------- Total 4,373 1,829 16,148,941 14,924,952
ARTICLE III
PENNING OF SALMON IN ORDER TO SECURE THEIR EGGS.
By C. J. Bottemanne M.D. [From a letter to Prof. S. F. Baird.]
_Bulletin of the United States Fish Commission_, Vol. 4, Page 169, 1884.
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