748 REPORT OF COMMISSIONER OF FISH AND FISHERIES. 



Log, utterly exhausted, " flottaut a la surface de l'eau sans faire aueun 

 mouveuient ; ou peut les prendre alors facilement a la main." 1 



As regards the second question, how does it come that th,e salmon 

 does not eat anything in fresh water, there are two ways of explain- 

 ing this fact. Either the fresh water (the Ehine) does not offer any suit- 

 able food, so that it cannot eat anything, or the salmon on entering the 

 fresh water loses all desire for food, so tbat it does not want to eat any- 

 thing. Regarding the first point, it is well known that the Rhine at any 

 rate does not offer much food for fish. The salmon, especially, finds but 

 little of its favorite food in the Rhine. T. Olsson 2 has made observations 

 regarding the food of different species of fish on the coast of Scandi- 

 navia, and has, among the rest, also examined twelve specimens of 

 Irutta solar. He says, regarding the contents of the stomach : u It is 

 often empty, or contains a yellow mucus, (from the fresh-water crus- 

 taceans?) small fishes, (in seven specimens,) especially Ammodytes and 

 Gasterosteus aculeatus, (in twelve specimens,) young fish, likewise crus- 

 taceans, viz, small decapoda macroura and isopoda, and Mysis vulgaris, 

 according to Lilljeborg, (K. Vetensk. Ak. Fork., 1852,) and, in one case, 

 a large coleopterous insect {carabusf was found." If we inquire into 

 the place of sojourn of these animals, we find tbat the Ammodytes lives 

 exclusively, and the above-mentioned crustaceans almost exclusively, in 

 the sea. Gasterosteus aculeatus is frequently found in the region of the 

 Rhine, u but prefers the small brooks flowing into the Rhine, Main, 

 and jSTeckar," (Siebold, op. cit., p. 67,) and it would, therefore, be dif- 

 ficult for the salmon to get at it. The carabus must have been eaten 

 in the neighborhood of the coast or the mouth of a river, as no insects 

 are found in the ocean. As regards the mucus, Olsson would, on exam- 

 ining it microscopically, in all probability only have found torn epithe- 

 lial cells, blood-atoms, &c. If, therefore, the absence of its favorite 

 food would force the salmon to eat less while in the Rhine, it is very hard 

 to believe that the salmon would not be able to find a substitute for its 

 favorite food in the river. If it eats young fish while in the ocean, why 

 should it not do the same while in the river, though, perhaps, the young 

 of different species of fish? If in the ocean, or near the mouth of a 

 river, it eats a carabus, why should it not hunt for insects while in the 

 river! It seems to me that the want of suitable food is not the reason 

 why it does not eat anything in the river. I am rather inclined to think 

 that life in fresh water produces a certain morbid disgust with all food 

 in the salmon; and not only in the spawning salmon, in which this pecu- 

 liarity is not so striking, but also in the winter-salmon, which does not 



1 Valenciennes, op. cit., p. 179. (Floating motionless at the surface of the water ; they 

 may then easily be caught with the hand.) 



*Ols8on, Iakttagelser, &c, p. G. 



3 Ohson examined two specimens of Tratta irutta; in the one, he found nothing, and, 

 in the otber, fourteen CUpea ftprattus and three Ammodytes. 



