SPAWNING OF THE WHITE-FISH. 



519 



"November 19. Same as yesterday; no White-fish to be seen. Caught some of the herring 

 with the dip-net; found their spawn still hard and small; their stomachs were full of White-fish 

 spawn. Mr. Clark and I took a boat with two men and dredged in the river, obtaining a quantity 

 of White-fish eggs. Nearly all were dead. Afterwards dipped a quantity from the pond, nearly 

 all of which were dead. 



"November 20. Made another visit to the island. No White-fish seen in the pond. Cold, 

 free/ing weather. 



"On the 24th and 25th of the month, while at Saudusky, Ohio, numbers of White-fish were 

 found with the spawn in different stages of ripeness, though a majority of them had spawned. 



"After spawning, the abdomen of the female fish is somewhat flabby and wrinkled, and the 

 fish is undoubtedly relaxed and weak; but not to the extent that the Salmon, as well as certain 

 other species of the Coregoni, are said to be reduced. The male shows but little indication of 

 weakness. 



"A series of ovaries were preserved from fishes of different sizes, and a count made by weigh- 

 ing the entire ovaries and then counting the eggs of a definite fraction, and calculating from it the 

 number of the whole. Accurate scales were used for this work, and the table may be relied upon 

 as correct : 



"This makes an average of about ten thousand increase for every additional pound weight in 

 the fish, which is precisely Mr. Seth Green's estimate, from his observations in spawning White- 

 fish. Considerable variation in the weight of an equal number of eggs was observed, depending 

 upon the stage of development at which they had arrived in the ovaries. During the spawning 

 season, the fish from the river were found to have very little in their stomachs. 



(ii) Development of egys and embryo. "It has been proven by repeated observations by fish- 

 culturists that the higher the temperature of the water in which the eggs are placed the more 

 rapidly the embryo fish develops within the t-gg, and the sooner it escapes from its inclosure in the 

 shell. The temperature of the succeeding mouths after the spawning period probably regulates 

 to a considerable extent the time of hatching of the White-fish in the Lakes. 



" On the llth day of April, at Ecorse, on the Detroit Eiver, I visited Grassy Island in company 

 with Mr. George Clark. The inside of the bag of a seine was lined with milliuet and dragged in 

 the river, bringing ashore a great quantity of mud and the small forms of life inhabiting the 

 bottom. Sifting and washing out the mud resulted in finding one little worm-like fish-embryo, 

 one-half inch in length, which I at once suspected to be the specimen sought after. Other 

 attempts with the seine failed entirely of taking any more. Mr. Clark then proposed that we 

 take a boat and search carefully on the surface for the young fish. Taking a pail and dipper, we 

 shoved off our boat, and Mr. Clark pulling very slowly with the oars, I hung over the gunwale, and 

 in a very few minutes found a little, active fish swimming with his head at the surface, and captured 

 him with the dipper. He proved to be identical with the one taken with the seine. In the course 

 of half au hour we captured forty, all of the same size and state of development. Most of them 



