EEPOET OF COMMISSIONER OF FISH AND FISHERIES. LV 



made with him to secure a series of the fishes, for the purposes of the 

 Commission, and the necessary alcohol beings provided, a very interesting 

 collection was made by him. He will himself prepare a report on the 

 subject for publication. 



C— PEOPAGATION AND INCREASE IN SUPPLY OF FOOD- 

 FISHES. 



20. — BY PROTECTIVE MEASURES ENFORCED WHEN NECESSARY BY LAW. 



As explained in previous reports, the duty first assigned by Congress 

 to the United States Fish Comrjission was that of investigating the 

 condition of the fisheries of the rivers, lakes, and seas of the United 

 States, as compared with that in former years, and of suggesting meas- 

 ures for protecting and increasing the suppl3\ It was not until the 

 second year, or 1872, that the subject of the propagation of the food-fishes 

 was added. This division of the work, however, has increased year by 

 year, until now it represents by far the largest portion of the expend- 

 iture. 



Preventing icillful and wasteful destruction of adults or young. — There 

 are a number of methods by which the increase in the supply of fishes 

 in a given region can be brought about. The simplest of these is the 

 avoidance of their capture at improper times and of their willful destruc- 

 tion. All desirable fishes should be spared as much as possible during 

 the spawning season, as it is at such times that they are exposed to 

 special danger. A fish that has safely escaped to the period when the 

 eggs and milt are ripe for the purpose of propagation should be per- 

 mitted to perform that function without interference. Of course, after 

 the eggs are deposited with the assurance of their development and the 

 growth of the young, the parent fish cease to be of any serious moment, 

 especially as one act of spawning is all that many kinds ever perform. 

 When taken, however, before spawning, the expectancies of future yield 

 are necessarily nullified. Legislation in this direction has been directed 

 more particularly to the protection of the salmon and the trout ; the close 

 time usually beginning a month or two before the ripening of the eggs. 



In the case of shad the prohibition of capture after some date in June 

 has been found very serviceable. 



JExvlusion of poisonous or injurious icaste from the waters. — Another 

 method of securing an increase consists in taking the necessary meas- 

 ures to prevent the introduction of foul waste, such as will either kill 

 or injure the adult fish or young, or interfere with the development of 

 the eggs. Under this head may be mentioned poisonous matters from 

 factories, such as paper and dyeing establishments, and gas and ammo- 

 nia works ; also the refuse of saw-mills, the saw dust getting into the 

 gills of the parent fish, or else covering up the spawning beds, so that 

 these will not discharge their proper functions. 



