tion of these dams, remained in the reservoirs and grew to weigh, 

 frequently, as much as ten pounds; these reproduced until the reser- 

 voirs have been stocked. As the supply of fish increased the quan- 

 tities of food lessened, so that the salmon have gradually decreased in 

 weight until now, after nine years, they do not average more than 

 two pounds. P^'rom the fact that, when food was in abundance, they 

 grew to weigh from eight to twelve pounds, and that, as they increased 

 in numbers, they averaged less in size, but still continued to spawn 

 and produce young fish, it would seem that the Sacramento salmon 

 may be successfully introduced into large lakes in the interior of the 

 continent, where, in consequence of dams or other obstructions, they 

 would be prevented from reaching tlie ocean. The history of this 

 fish in these small reservoirs shows, that all that is requisite for their 

 successful increase is the abundant supply of food, to be found in 

 larger bodies of fresh water. Salmon, fully mature, weighing two 

 pounds, and filled with ripe eggs, were taken, in September, eighteen 

 hundred and seventy-seven, in the waters of San Leandro Reservoir. 

 These fish were hatched in the stream which supplies the reservoir, 

 and by no possibility had ever been to the ocean. The San Leandro 

 is a coast stream, not exceeding fifteen miles in length, and empties 

 into the Bay of San Francisco. It contains water in the winter and 

 spring, at which time, before the reservoir was constructed, the sal- 

 mon sought its sources for the purpose of spawning. There was 

 never sufficient water in the months of August or September to per- 

 mit the fish to reach their spawning grounds. After the construction 

 of the reservoir, large numbers of salmon that came in from the 

 ocean in January and February were caught at the foot of the dam 

 and transported alive and placed in the reservoir above. The 

 descendants of these fish thus detained in fresh water and not per- 

 mitted to go to the ocean, have so far modified the habits of their 

 ancestors that they now spawn in September, instead of in January 

 and February. Inasmuch as these fish spawn in the McCloud, in 

 the headwaters of the Sacramento, and at the sources of the San 

 Joaquin, in the Sierra Nevada, in September, and in the short coast 

 range rivers, in January and February, and as, when changed to 

 other waters, their eggs ripen at a time when the conditions of their 

 new homes are most favorable for reproduction, they show a plastic 

 adaptability, looking to their future distribution, of much practical, 

 as well as scientific, importance. 



The statistics hereafter given of the temperature of the water 

 through which the Sacramento and San Joaquin salmon pass to reach 

 their spawning grounds, show that they swim for hundreds of miles 

 through the second hottest valley in the United States, during the hot- 

 test portion of the year, where the mean temperature of the air is 92° 

 Fahrenheit, and of the water, 75°. These statistics have been obtained 

 from the record kept by the Central Pacific Railroad Company, and are 

 for the months of August and September of the years eighteen hun- 

 dred and seventy-five, eighteen hundred and seventy-six, and eighteen 

 hundred and seventy-seven. They are of importance as showing 

 that the Sacramento salmon will enter rivers for spawning purposes, 

 where the water is so warm that the eastern salmon {sahno salar), if 

 it were to meet it, would turn back to the ocean. They are also 

 of importance as illustrating the probability that there are many 

 streams on the Atlantic Coast, from the Potomac to the Rio Grande, 

 into which this fish could be successfully introduced. 



