816 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 



is arranged and equipped with especial reference to the manipulation 

 of the embryos and minnows of whitefish [Goregonus olupeiformis), the 

 most valuable commercial species of the great lakes. Its nominal ca- 

 pacity is 100,000,000 eggs. 



" The water is furnished by the Alpena Water Company of Alpena, 

 being forced through wooden mains from Thunder Bay, an arm of Lake 

 Huron. A 2-iuch stream, under an average pressure of 20 pounds to 

 the square inch, connects with the hatchery, the discharge being regu- 

 lated by globe valves. The inlet pipe is laid underneath the building, 

 near the front, and is tapped by four perijendicular arms, each discharg- 

 ing into the top tank of one of the four systems of tanks for supplying 

 water to the hatching apparatus. Each system comprises a series of 

 four rows of tanks, one row above the other. There are two tanks to 

 each row, making eight tanks in the series, or thirty-two in all, each of 

 which is 15 feet long by 12 inches wide and 10 inches deep. One series 

 is the exact counterpart 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 stand 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 beiug used three 

 times over. Overflows are provided at the ends of the tanks, which 

 discharge into the next below. 



'• Each of these series of reservoirs is connected with larger tanks, 

 into which the minnows are carried by the current as soon as hatched. 



" The outflow openings of the tanks for the reception and storage of 

 the minnows are protected by finely perforated tin boxes of sufficient 

 dimensions to keep the little fish away from the vortex formed by the 

 escaping fluid, where they would be liable to injury from the strong cur- 

 rent. There are ten of these receiving tanks, with an aggregate capac- 

 ity of 7,000 gallons." 



Work on the building was begun October 1, and pushed rapidly for- 

 ward to completion. The inside work was completed and jars placed 

 in position in time for the first arrival of eggs, November 10. It should 

 be stated that, although the capacity of the hatchery is 100,000,000 

 eggs, a partial equipment was decided on for its first season, in accord- 

 ance with which only two hundred and eight jars were ordered and re- 

 ceived. 



The water is furnished free of cost by the company above referred 

 to, which derives its supply, for ordinary pur])oses, through pipes tap- 

 ping the bay a considerable distance above the city, where it is always 

 perfectly clear and pure. Another inlet main, however, is laid to the 

 river, just above the city limits; but this, fortunately, is opened only 

 in case of fire. This water is generally murky with sediment and im- 

 purities, as the river is the vehicle for floating down vast numbers of 

 logs from the pineries in the interior. Four fires occurred the past win- 



