STURGEON HATCHING ON THE DELAWARE RIVER. 339 



water that was absolutely fresh (New Hamburg, N. Y., Seth Green; Delaware Oity, 

 Del., Prof. Ryder; the Elbe). Current, on the other hand, could not have been alone 

 an essential condition, since in the fresh sluiceway at Delaware City, in the experi- 

 ments of Prof. Ryder, a circulation maintained stronger undoubtedly than in channel 

 waters. Nor could the effect of silt be regarded as alone the unfavorable element; 

 quantitatively in mid stream — especially of sturgeon waters — an amount of sediment 

 might be expected greater doubtless than a neighboring spring-fed pond. Mode of 

 temperature variations might, again, be looked upon as of problematic value. To 

 what degree, then, is the sum of all conditions to be regarded as essential for success 

 in sturgeon hatching ? In theory the problem is assuredly more troublesome than in 

 practice. 



As to obtaining simultaneously spawning fishes, male and female : In the event of 

 extensive culture this difficulty is one that in the opinion of the writer could not be 

 regarded as of serious weight. In a favorable locality each season brings a number 

 of spawners to the wharfs of the fishermen, and with a regularity of occurrence that 

 appears remarkable. In a letter to the writer, Mr. Reuben Anderson, of Delaware 

 City, well known as a careful observer of the habits of the sturgeon, predicted to a day 

 the appearance of spawners. He afterward stated that the " run " of fish,* though 

 brief — often not longer than a single day — might, in his long experience, with every 

 possibility be depended on. 



* A breeding habit of the sturgeon Mr. Anderson discussed with the writer, seems for cultural 

 purposes of the utmost significance. The earliest fish in their passage up the stream spawn farthest 

 from the river mouth, the next school in a locality not as distant, and the later fish in the lower stream 

 regions. This zonal distribution in spawning seems attested by the character offish as taken in their 

 journey past a single shore front; the earliest are uniformly "caviar fish" (i. e., of immature ovaries) ; 

 later are taken "runners" (i.e., ripe fish) ; and at the close of the spawning season none but "slunkers" 

 (i.e., those having spawned). 



