MANUAL OF FISH-CULTURE. 59* 



flour, aud middlings. The butchers' offal comprises livers, hearts, and 

 lights, which are collected from the slaughter-houses twice or thrice 

 weekly, and preserved in refrigerators until used. 



The flesh of old and worn-out horses has been used each year since 

 1892 in the same way as the butchers oft'al, with very satisfactory 

 results; the parts that could be chopped readily have been fed direct 

 to the fish so far as needed, and other parts have been used in the 

 rearing of maggots. 



^ext to chopped meat maggots have constituted the most important 

 article of food, and their systematic production has received much 

 attention. A rough wooden building has been erected for this branch 

 of the work, aud one man is constantly employed about it during the 

 summer and early autumn months. The maggots thus far used are 

 exclusively flesh-eaters, mainly those of two undetermined species of 

 flies; the first and most important being a small, smooth, shining green 

 or bluish-green fly, occurring in early summer and remaining in some- 

 what diminished numbers until October; and the other a large, rough,^ 

 steel-blue fly that comes later and in autumn becomes the predomi- 

 nating species, having such hardiness as to continue the reproduction 

 of its kind long after the occurrence of frosts sufficiently severe to 

 freeze the ground. 



To obtain maggots meat is exposed in a sheltered location accessible 

 to flies during the day. When well stocked with the spawn of the flies 

 it is placed in boxes, which are set away in the " fly-house " to develop; 

 when fully grown, the maggots are taken out and fed at once to the fish. 

 Stale meat, parts of the butchers' ofl'al and of tlie horse carcasses not 

 adapted to chopping; fish, fresh, dried, or pickled; fish pomace from 

 herring-oil works, and any animal refuse that comes to hand, are used 

 to entice the flies and afford nourishment for the maggots. Fresh fish,^ 

 when not too watery or oily, like alewives and herring, is very attract- 

 ive to the flies, and in proper condition may serve as well as fresh meat. 

 Fish dried without salt or smoke aud moistened before using is, when 

 free from oil, a superior article. Its preparation presents, some diffi- 

 culties, but in winter it is easily effected by impaling whole fishes on 

 sticks and hanging them up under a roof where they will be protected 

 from rain without hindering the circulation of the air; in this way 

 mauy flounders and other refuse fish from the smelt fisheries have been 

 dried. 



It is usually necessary to expose meat but a single day to obtain suf- 

 ficient fly spawn ; thelarviie are hatched and active the next day, except 

 in cool weather, aud they attain their full growth in two or three days. 

 To separate them from the reumauts of food the meat beariug the fly 

 spawn is placed on a layer of loose hay or straw in a box which has a 

 wire-cloth bottom, and which stands inside a slightly larger box with a 

 tight wooden bottom. When full grown, the maggots work their way 

 down through the hay mto the lower box, where they are found nearly 

 free from dirt. 



