CULTURE OF THE WillTE-FISH. 535 



"The losses in the fry stage merit consideration, though there is every evidence to believe 

 that they are very small. One great advantage in favor of the young White-fish is its strength 

 and vigor almost from the time it leaves the egg, and its disposition to seek the surface, as 

 observed in the troughs and where they were seeu in their natural condition in Detroit River." 



DISEASES. Nothing definite has been ascertained regarding the diseases to which White- 

 fish are liable. A roughness, however, on the scales may be observed from about November 15 

 to November 20. This roughness has the appearance of small tubercles, and is most apparent on 

 the sides. toward the vent. The male fish is said to exhibit this possible symptom of disease the 

 more plainly. 



Mr. Milner's observations on the White-fish, with regard to its being infested with parasites, 

 led him to write : 



" The White-fish, as far as my observations have extended, is infested with two external and 

 two intestinal parasites. The external ones are a crustacean, a Lerncea, and an annelid, the Ichtlty- 

 obdella pitnctala. The lernean was found only in the Detroit River, adhering to the fish on the 

 dorsal region, and with its bell-shaped sucker buried in the epidermal sheath of the scales. On 

 the "White-fish swimming in schools near the surface around the edge of the pond in Detroit Eiver, 

 it could be detected by close examination fastened to the fish. There were seldom more than four 

 on one fish. The Lake Herring, confined in the same pond, swam in close contact with the White- 

 fish, but in no instance, although careful observations were made repeatedly of the Herring while 

 in the water and after capture, was the lernean found upon them. In Lake Superior they are 

 found to be numerous on the siscowet. 



" The Ichtkyobdella, a leech of three-fourths of an inch long, grayish- white in color, with 

 brown tesselated markings, was seen in great numbers in the mouth of April, while the .fishermen 

 were lifting their nets from about fifty fathoms some fifteen miles out from Kenosha, Wisconsin. 

 They covered the nets and fishes of all species, and fell in such numbers on the deck that it became 

 slippery, and an old coat was thrown down for the man who was lifting the gang to stand upon. 

 They were very tenacious of life, living for a long time on the deck, and for several days in the 

 bilge-water of the fish-boats. They were in such numbers that it was difficult to decide whether 

 they had a preference for any species, and were found filled with blood both in the gills and while 

 attached to the body, though it was difficult to imagine that they could fill theinselves with blood 

 from the epidermal sheath of the scales. They were thought to be most numerous on the White- 

 fishes, as they were in greater numbers on them than on the Trout, the Lawyer, or the Cisco, the 

 only other fishes takeu. 



"A prevailing but mistakeu opinion in the vicinity was that the White-fish fed upon the leech. 

 Dr. Hoy's investigations disproved the notion, and all examinations of stomach contents confirmed 

 this fact. One of the intestinal parasites resembled the leech somewhat in form. The other was 

 an EdttHorlty-ncltiis. They were never found within the stomach, but always in the duodenal 

 portion of the intestine near the mouths of the crecal tubes." 



METHODS OF CAPTVIJE. The methods employed whereby the largest numbers of this fish 

 may be taken varies in different localities. At Whitetish Point, Lake Superior, the greater 

 part of the catch is made with pound-nets. About the Apostle Islands the gill-net is used 

 at all times. The best grounds are along the shore from Ashland to Ontonagou. From Grand 

 to Sauk's Island the catch of White-fish is made with pound-nets in the spring and gill-nets in 

 the fall. At the south end of Lake Michigan there are no pound-nets; the fish, consequently, are 

 of large size. The White-fish fishery of Saint Joseph is carried on far out in the lake, formerly 

 nearer shore. About Little and Grand Traverse Bays all the pounds were blown away on 



