13 



The young salmon, from the time they first begin to feed, 

 FOOD. eat almost anything they can get, but they show a prefer- 

 ence for insects and insect larvae, and they prefer to cap- 

 ture food that is floating on the surface of the water. An examination 

 of the contents of the stomachs of the young salmon taken from Paper 

 Mill Creek and its tributaries, from the time they were planted to the 

 time they reached salt water, shows that their food was almost exclu- 

 sively flying insects which had dropped upon the surface of the water. 



These streams abound in caddice worms of three or four species, 

 small periwinkles, the larvae of stone-flies, may-flies, and other insects; 

 but they were all neglected for the flies, bees, beetles, caterpillars, etc., 

 that fall into the stream. No caddice worms or periwinkles were found 

 in their stomachs, and but very few of the larva 1 of aquatic insects. 

 This same thing was observed in the younger trout; and although the 

 larger trout eat large quantities of caddice worms, the insect larvae in 

 the water do not furnish the amount of food to these fish that is 

 popularly supposed. 



Although these salmon live almost exclusively on insects that drop 

 upon the water, we have found in their stomachs pieces of leaves and 

 buds, small feathers, shells of salmon eggs, and the helpless young of 

 their own species. (See notes on planting of salmon fry before yolk sacs 

 were absorbed, at Sisson, November, 1897.) 



In the salmon taken in brackish water I found they had been eating 

 small salt-water crustaceans, and one three-inch salmon taken in salt 

 water had eaten six of the young of the " silver smelt" (Atherinops 

 affinis) and one small leaf-hopper of the kind that is found among the 

 pebbles along the shore of the bay. 



In almost every case the stomachs were filled to their utmost with 

 food. Tomales Bay abounds in small crustaceans and the young of 

 the "silver smelt," and the young salmon would have no trouble in 

 finding an abundance of food on reaching salt water. 



Scarcely any vegetable matter was found in their stomachs, and what 

 little was found no doubt was taken by accident. 



If these young salmon live almost exclusively on flying insects, the 

 way to choose a good stream for planting would be to select one with 

 plenty of trees, bushes, and grass along its banks, for such vegetation is 

 a harbor for insects. 



The principal source of danger to young fish in a stream 



ENEMIES, is from predaceous fishes, or even from older fish of their 



own kind: Of the four species of fish in these Harm 



County streams chub (Rutilus symmetricus) , stickle-back (Gasterosteus 



cataphraclus) , blob (Cottus gulcrsas), and trout (Salmo gairdneri) the 



last two only are" predaceous. 



