SOME ANIMALS AND CONDITIONS INIMICAL 

 TO FISH EGGS AND LARVAE IN THE SEA 



By Professor Edward E. Prince, LL.D., D. Sc, Etc., 

 Commissioner of Fisheries for Canada. 



As one of the pioneers in the study of the eggs and 

 young stages of marine food fishes, I remember an opin- 

 ion expressed long ago by high authorities that the sea 

 might be over-crowded with fish were there not some 

 effective means in existence for checking their increase. 



COD AND OTHER MARINE FISHES MOST PROLIFIC. 



At that time the number of species of marine and 

 fresh water fishes, exclusive of sharks, etc., known to 

 science, was about 12,000, and as I stated in a paper 

 on fish eggs published in 1886, the eggs of not more than 

 80 species had been discovered and described.* At the 

 present time over 100,000 species of Teleosteans are 

 known to Ichthyologists and the eggs and something of 

 their larval development are known of about 350 species. 

 As long ago as 1864, G. 0. Sars in Norway had shown 

 that cod, mackerel, haddock and, I think, gurnard 

 (Trigla) eggs, floated near the surface of the sea, and 

 J. A. Ryder and others in this country, Mcintosh in 

 Scotland, G. Brook, J. T. Cunningham and others in Eng- 

 land, proved the same thing of these and a number of 

 other species, and pointed out that the eggs were pro- 

 duced not by thousands, as in the case of salmon, trout 

 and herring, but by millions. Their eggs were stated 

 to be not large and heavy and deposited on the bottom 

 of the water; but quite minute, almost microscopic in 

 size (30 or more in a row extending barely over a linear 

 inch) and so transparent as to be nearly invisible, while 

 their small specific gravity caused them to float near the 

 surface of the sea. The number of eggs produced annu- 

 ally by most of the important marketable fish to which I 



*0n the Presence of Oleaginous Spheres in the Yolk of Teleostean 

 Ova. Annals of Natural History, London, 1886. 



