170 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



85 — ITIEITIORAIVOA REIiATIVE TO IIVCI.OSURES FOR THE COIVFIIVE- 

 MEIVT OF SAIvMOIV, DRAWIV FROITI EXPERIENCE AT BUOK8PORT, 

 PEIVOBS€OT RIVER, ITIAIIVE. 



By CHARLES O. ATKIIVS. 



[In response to request of Dr. C. J. Bottemanne.] 



The Penobscot salmon-breediug establishment was founded in 1872, 

 at Bucksport, in the State of Maine, near the mouth of the Penobscot 

 Kiver. The location was primarily determined by the necessity of being 

 near a supply of living adult salmon, to be used for breeders. After an 

 exploration of the headwaters of the Penobscot, which lie mostly in an 

 uninhabited wilderness, the conclusion was reached that the chances of 

 securing a sufficient stock of breeders were much greater at the mouth 

 of the river, where the principal salmon fisheries are located ; but to 

 avail ourselves of the supply here aftbrded we must take the salmon at 

 the ordinary fishing season, May, June, and July, and keep them in con- 

 finement until the spawning season, which is here the last of October 

 and first of November, As the salmon naturally pass this period of 

 their lives in the upper parts of the rivers, it was thought essential to 

 confine our captives in fresh water. Later experiments in Canada indi- 

 cate that they will do as well in salt water, but the construction and 

 maintenance of inclosures is much easier when they are located above 

 the reach of the tide, to say nothing of the proximity of suitable fresh 

 water for the treatment of the eggs. In the precise location of the in- 

 closures several changes have been made, but they have always been 

 in fresh water, and within convenient distance (5 to 10 miles) of the place 

 where the salmon were captured. , 



In our experiments and routine work we have made use of four in- 

 closures, which I will now describe. 



No. 1. — In Craig's Pond Brook, a very pure and transparent stream, 

 an artificial pond 40 square rods in area and 7 feet in extreme depth, 

 was formed by the erection of a dam. The bottom of this pond was 

 mainly a grassy sod newly flooded. About half the water came from 

 springs in the immediate vicinity, and the rest from a very pure lake 

 half a mile distant. The water derived from the lake was thoroughly 

 aerated by its passage over a steep rocky bed. The transparency ol 

 the water in the pond was so great that a pin could be seen at the depth 

 of 6 feet. This inclosure was a complete failure. The salmon placed 

 therein were after a day or two attacked by a parasitic fungoid growth 

 on the skin, and in a few days died. Out of 59 impounded not one 

 escaped the disease and only those speedily removed to other waters 

 recovered. Several, removed in a very sickly condition to the hike sup- 

 plying the brook, recovered completely, from which it is safe to infer 

 that the cause of the trouble did not lie in the lake water. Of the spring 



