[9] THE LONDON FISHERIES EXHIBITION. 1193 



striictiou of a pass, aud which had beeu stocked with several hundreds 

 of thousands of artificially hatched fish, the rent of the fisheries after a 

 few years yielded the large sum of £27,000 sterling [about $135,000]. 

 On a still larger scale are the results which have been reached by the arti- 

 ficial hatching of salmon in America, as in the Sacramento River, where, 

 according to Prof. Spencer F. Baird, the yield was annually increased 

 by 5,000,000 pounds, and where more salmon are caught than can be 

 used by the numerous factories for preparing fish. In Germany, like- 

 wise, the young salmon which have been planted here and there, though 

 on a very modest scale, have proved a decided success, making it ex- 

 ceedingly desirable to pursue energetically this path, which has been 

 recognized as the right one for increasing the number of these fish. 



Summer spawners. — For feeding the masses, however, the fish 

 which spawn in summer, and which are found in our numerous rivers 

 and lakes, are, for Germany, of far greater importance than the salmon- 

 oids. Their propagation is easier, can be accomplished without any 

 special apparatus, and is even now very successfully carried on in many 

 places in Germany. I was much interested, when in London, to learn 

 from reports from distant countries that, contrary to the opinions that 

 the increase of fish which spawn in summer is a mere useless play, 

 the fishermen are not in the least to biame as regards the decrease of 

 fish in our inland waters, but that this is caused simply by river im- 

 provements and the pollution of the water ; yet in localities where river 

 improvements and the i)ollution of the water are unknown the number of 

 fish has been noticeably decreased simply by too exhaustive fishing. 

 In Canada, for example, lakes 400 to 500 miles long have been depleted 

 of fish from this cause, and in the Volga the size of the various kinds 

 of sturgeon has decreased for the same reason ; so that the weight of 

 the roe, which, comparatively speaking, is much greater in large than 

 in small fish, and which twenty years ago was one nineteenth of the 

 total weight of the body, has decreased steadily, until it is now only 

 one forty -fourth. Facts like these ought to cause serious thoughts, even 

 with those peox)le from whom we are accustomed to hear again and again 

 that, compared to the destruction of fry and fish by natural enemies, the 

 violence of man is without any noticeable influence as regards the num- 

 ber of fish; the same people, strange to say, complain in one and the 

 same breath, that if the fisheries are limited the number of fish will 

 become too great, and that consequently the individual fish can no 

 longer reach their j)roper size. In making such assertions people have 

 hardly thought of the last conclusions to be drawn therefrom, viz., that 

 in the inclosed waters of thinly i)opulated districts all fish must become 

 dwarfed. 



Pollutions. — The hurtful influence of river improvements and the 

 pollution of water by factories, &c., can, of course, not be denied, and 

 everywhere efforts are made to keep the waters pure without interfering 

 with the manufacturing interests. At the London Exhibition the jSTa- 



