4 ARTIFICIAL PROPAGATION OF STURGEON. 



were not sufficiently matured to void the secretion by the applica- 

 tion of external pressure. The milt was separated from the cut 

 testes by straining through a coarse cloth and proved just as effec- 

 tive as that taken from live fish, even after being held for several 

 minutes in the rubber-bulb container. In an effort to overcome 

 past troubles, the style of hatching apparatus was changed. The 

 eggs were spread evenly under water on shallow trays in boxes 

 whose sides and bottoms were covered with metal gauze. The ne- 

 cessity for quick handling soon became apparent, as the viscid nature 

 of the eggs causes them to cling so firmly to any surface with which 

 they come in contact that they are invariably injured in the attempt 

 to loosen them, and it wias found that if not placed on the trays 

 within 10 or 15 minutes after being fertilized they would form into 

 a gluelike mass, which speedily became compact and hard. After 

 allowing sufficient time for the eggs to become firmly attached, the 

 trays containing them were fitted into the boxes and anchored in 

 various places in the river bed. 



By the end of the second day thereafter the eggs in the boxes, 

 which had been moored in marginal waters having a sluggish cur- 

 rent and carrying much silt, were found to be entirely enveloped 

 in fungus and dead. Those placed where the water current was 

 strong and comparatively free from sediment had sustained a loss 

 of 60 per cent by the close of the fifth day from the same cause, 

 while those which had been installed in a strong current in salt 

 water showed practically no fungoid growth and were hatched in 

 good condition. 



In the spring of 1890 Frank N. Clark, superintendent of the 

 Northville (Mich.) station, made preparations for the collection of 

 sturgeon eggs at Fox Island, Mich., and under his direction 142 

 female and 32 male fish were examined between May 26 and June 14. 

 Examination showed that 23 of the females had already spawned, 

 98 were very immature, the eggs in 6 were nearly ripe, and 5 were in 

 spawning condition. Of the males 21 were hard, 2 almost mature, 

 and 9 entirely so. In all, 20,000 eggs were secured and fertilized 

 by cutting open and squeezing the milt sacs after moistening them 

 with water. Much difficulty was experienced from adhesion, three 

 hours of constant stirring being required to break up and separate 

 the bunches of eggs. Ninety-five per cent of them were developed 

 to the eyed stage, but shortly afterwards a growth of fungus began 

 spreading in the floating boxes in which they were being incubated, 

 and, as a result, very few of the eggs were hatched. Had it been 

 possible to incubate them in Avhitefish jars it is estimated that at 

 least 85 per cent would have been saved. 



In the course of experimental work conducted in 1901 on the Mis- 

 sisquoi and Lamoille Rivers, tributary to Lake Champlain, efforts 

 were made to hold green sturgeon in artificial inclosures for ripening. 

 These efforts proved utterly futile, as in every instance the eggs 

 caked together in a hard mass and development was arrested. Not- 

 withstanding the great difficulty experienced in securing ripe eggs 

 and milt together, 1,500,000 eggs were taken and fertilized, and 

 their viscosity was effectively overcome by the method that is em- 

 ployed for the separation of pike-perch eggs. They were then suc- 

 cessfully hatched in McDonald jars, the incubation period being 



