1220 FISHERIES OF THE UNITED STATES. [6 6 J 



ISTorthville hatching-house — Continued. 



various kinds of apparatus, consisting of Clark troughs, hatch: 

 ing jars, nursery tanks, and sorting and packing tables, being 

 represented. Frank TsT. Clark, superintendent. 57,1G8. TJ. S. 

 Fish Commission. This hatchery was established by N.' W. 

 Clark for the propagation of brook-trout, but for some years it 

 has been used by the U. S. Fish Commission as a collecting and 

 developing station for eggs of the whitefish (Coregonus clupei- 

 formis), and during the past season (1882-'S3) not less than 

 50,000,000 eggs have been handled here. These were shipped 

 to various localities in the United States and Europe. 



The United States fish-hatchery, Alpena, Mich. 



This hatchery was built in the fall of 1882. It is a one- story frame 

 building, 30 feet wide by 60 feet long, having front and rear 

 entrances, and amply lighted by 14 windows. The main floor 



v . includes the hatching room, and an office and sleeping apart- 



ment, 10 feet wide by 18 feet long, the space between this office 

 and the opposite side being conveniently utilized for storage of 

 tools, cans, egg-cases, &c. The hatchery is arranged and 

 equipped with especial reference to the manipulation of the em- 

 bryos and minnows of whitefish (Coregonus clupeiformis), the 

 most valuable commercial and food species of the Great Lakes. 

 Its nominal capacity is 100,000,000 eggs. The water is fur- 

 nished by the Holly Water Works Company, of Alpena, being 

 forced through wooden mains from Thunder Bay, an arm of 

 Lake Huron. A 2-inch stream, under an average pressure of 20 

 pounds to the square inch, connects with the hatchery, the dis- 

 charge being regulated by globe valves and ball cocks The inlet 

 pipe is laid underneath the building, near the front, and is tapped 

 by four perpendicular arms, each discharging into the top tank 

 of the four systems of tanks for operating the hatching vessels. 

 Each system comprises a series of four rows of tanks, one row 

 above the other. There are 2 tanks to each row, making 8 

 tanks to the series, or 32 in all, each of which is 15 feet long by 12 

 inches wide by 10 inches deep. One series is the exact coun- 

 terpart of another. A row of faucets on either side of the top 

 tank, into which the water first enters, supplies two rows of 

 hatching jars or incubators, which rest on shelves placed across 

 the second tank below and discharge into the tank between, 

 which in turn feeds a second series of jars, and so on. In this 

 way the four rows of a series operate three double rows of jars, 

 the water being used three times over. Overflows are provided 

 at the ends of the tanks which discharge into the next below. 

 These series of tanks all connect with larger storage tanks for 

 the minnows. Into these the current carries the minnows as 



