22 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



it successfully. Each schooner could be provided with a circular of 

 instructions and such vessels (large, shallow pans) as would be needed 

 to insure the intimate contact of spawn and sperm when mixed. It may- 

 even be deemed advisable, though this seems hardly necessary, to place 

 experienced spawners on vessels which would make favorable terms, to 

 conduct the operations. 



In x^re^senting this suggestion one additional factor needs to be 

 emphasized. While the exact spawning habits of the mackerel are 

 unknown, the i)robability is that this function is accomi^lished while 

 the males and females are actively swimming about together at a 

 greater or less depth below the surface. The spermatozoa are probably 

 more or less widely disseminated through the water. The ova are 

 squirted out in a stream, and, being at this time highly buoyant, imme- 

 diately begin to rise toward the surface, the micropyle, through which 

 alone the spermatozoan may enter, being downward. Under such cir- 

 cumstances many ova must escape fertilization. That such is the case 

 is shown by the very considerable number of unfertilized eggs which 

 were observed among those of the mackerel collected in the surface 

 towings this summer, and still better by my observations on the eggs of 

 the cunner, of which fully 30 j>er cent of those examined had failed of 

 fertilization. This shows that one very considerable advantage of arti- 

 ficial over natural propagation of pelagic fish ova is derived from an 

 increased effectiveness of the means of bringing the sexual elements , 

 into contact. No doubt much may be gained by continuing the care of 

 the developing ova to a later stage, when the means for so doing, as in 

 the case of the shad, is effective: but when, as is at present the case 

 with the mackerel, there are lacking facilities for prosecuting the work 

 further under such circumstances as will insure a profitable scope of 

 operations, it seems best to adopt the merchant's dictum of '' small 

 profits and large sales." No doubt the time will come when the means 

 will be provided for carrying the eggs collected in this way up to the 

 time of hatching. 



It needs also to be pointed out that most of the eggs which would 

 be produced by spawning schools thus captured are now entirely lost, 

 and that this fact alone, in the case of the lobster, has been regarded 

 as sufficient to commend the present mode of propagating that species; 

 although here what was said above of the advantage to be gained by 

 artificial fertilization is not applicable. 



The advantages of this plan are economy and the possibilities of 

 extensive operations; the disadvantage is its probable uncertainty 

 from year to year. 



