Man and Nature 



431 



may be truly said to have ''its heart in its throat." The 

 tail meanwhile is forming and head and tail bend toward 

 each other until they almost touch, while the yolk sack appears 

 like a great tumor upon the belly of the young fish, which 

 soon begins to try its muscles in spasmodic jerks and 

 twists. Prior to hatching the little embryo is surrounded 

 by the delicate and highly extensible membrane which sur- 

 rounded the egg. At time of hatching this membrane is 

 broken, the food stored in the yolk sack is soon absorbed, 

 and the young fish begins to "rustle for a living." At this 

 stage the fry may be set free in the river, or if suitable ponds 

 are available, they may best be kept at home and fed on 

 chopped liver, meat, milk curds, etc., for several months until 

 they are better able to take care of themselves. For the whole 



DEVELOPING FISH 



Showing yolk sack. From Kunz Eadcliffe, Bulletin of the U. S. 

 Bureau of Fisheries, Vol. 35. 



principle of fish culture is that a greater per cent of eggs will 

 be fertilized artificially than in nature, and a larger number 

 of them will develop safely in the care of the hatchery than 

 if exposed to their hosts of natural enemies. 



While the seal and whale are not fishes, the Bureau of 

 Fisheries, on the basis of the old scriptural classification of 

 "beasts that swim," has included them and all other creatures 

 aquatic in the field of its activity. The fur seal industry is 

 but one among many examples of the influence of natural 

 wealth upon human history. The fur seals of the Pacific are 

 grouped in two main herds, those of the Pribilof, and those 

 of the Commander Islands. The former are part of Alaska 

 and the latter of Siberia. The former herd was discovered in 

 1786 by the Russian navigator Pribilof, whose name is borne 

 by the islands of his discovery, and the latter in 1741 by the 

 naturalist Steller who accompanied the ill-fated Behring on 

 his second and final voyage in 1741. A few years ago the 

 seals were threatened with extinction, the Pribilof herd having 

 suffered reduction from its original number of four or five 



