820 BULLETIN OF THE BUREAU OF FISHERIES. 



the well-known transverse black bands, the small red spots, etc., for a more 

 convenient traveling suit of silvery gray, and in this condition they are called 

 "smolts." 



The main river, which has served for the passage of the yearlings on their 

 way to the ocean, a few years later conducts the grown-up fish to their spawning 

 places; so the river itself is mainly the binding link between the sea, where the 

 salmon grow up from 15-centimeter large trout-like fish to marketable salmon, 

 and the upper region, where the propagation takes place and the young salmon 

 find a living until they are about 1 year old. The food the young salmon 

 take in the main river during their journey to the sea consists of different 

 insects, and in the lower parts of the river and the estuaries small crustaceans. 

 During the ascent of the larger fish coming from the sea and bound for the 

 spawning places in the river, as a rule no food whatever is taken. The salmon 

 caught during their ascent owe their value as food for man to the rich feeding 

 grounds in the open sea. So it is perfectly right to consider them as a gift 

 from the sea to the lands bordering on the river, the inhabitants of which catch 

 them on their passage. But taking into consideration the fact that the salmon 

 swim up the river at the expense of the fat stored in their muscles, etc., from a 

 general economic point of view it is also evident that the fish are in finest con- 

 dition on entering the river, and that therefore the lower parts of the river are 

 most to be recommended for the catching of the salmon. 



Now, keeping constantly in our mind the importance of the upper regions 

 of the river and its tributaries for the first year of the salmons' life and that of 

 the open sea for their growth until they shall have reached marketable size, 

 I shall first of all point out to you that this normal course of development is 

 not followed by those young salmon which at the end of their first year remain 

 for a second year, and some of them longer still, at or in the neighborhood of their 

 birthplaces. These are nearly all male fishes, and it is a well-established fact 

 that they will be sexually mature (ripe) in the second autumn of their existence, 

 and then even will play an active part in the propagation of the species. Their 

 size is (October-November) from 15 to 19 centimeters, very few being smaller 

 or larger than that size. It has been suggested by Professor Fritsch for the 

 salmon of the river Elbe that all the young males may remain a second year in 

 the upper parts of the river and its affluents. I have been able myself to show, 

 however, that this by no means holds good for the Rhine. I had the opportunity 

 of examining 365 young salmon caught in May during their descent to the sea 

 in one of the mouths of the Rhine, and'measuring from 12 to 17 centimeters, and 

 I fovmd that 136 (37 per cent) of these were males and 229 (63 per cent) females. 

 Males and females were exactly of the same sizes, and it can hardly be doubted 

 that they were all of them i -year-old fishes. That there was a majority of 

 females may, of course, be considered in connection with the circumstance 



