J. PISCICULTURE AND THE FISHERIES. 431 



States has been very satisfactorily answered by a recent 

 communication of Mr. P. B. Redding, one of the Fish Com- 

 missioners of California. This gentleman reports that on 

 the 15th of last August salmon commenced running up the 

 San Joaquin River, passing the bridge across that stream, in 

 latitude 36 30', longitude 120, in large numbers, appearing 

 in size and general character identical with the Sacramento 

 fish. At that point they must have passed for one hundred 

 and fifty miles through the San Joaquin Valley, in which 

 the mean temperature of the air at noon, in the shade, for 

 the summer, has been about 104, the temperature of the 

 water at the surface from 80 to 86, and that at the bot- 

 tom from 75 to 80. The mean depth of the river has been 

 found to be four feet seven and three-eighths inches. 



It is very doubtful whether this water temperature is ex- 

 ceeded in any part of the United States ; certainly not in 

 any of our larger rivers, nor in such as would be suitable for 

 the existence of the California salmon. 



It is well known that the Eastern salmon becomes uncom- 

 fortable when the temperature of the water reaches 65, 

 w T hile a higher degree of temperature drives them back to 

 the sea in search of cooler quarters. 



SALMON TEADE OF THE COLUMBIA EIVEE. 



The salmon trade on the Columbia River during the sea- 

 son of 1875 has been one of remarkable prosperity, the un- 

 favorable indications at the outset not having been con- 

 tinued. Of fourteen canning establishments on the river, 

 twelve were in operation, and put up in all 275,000 cases, 

 each case containing four dozen one-pound cans, the largest 

 number being put up by A. Booth & Co., at Astoria, or 

 34,000 cases. A large quantity of fish has also been packed 

 in tierces and barrels, the weight of which has not been 



given. 



An important addition has been made to the usual treat- 

 ment of these fish in the utilization of the heads for the pur- 

 pose of extracting the oil, about nine thousand gallons hav- 

 ing been obtained by Messrs. "Watson & Co., of Manhattan, 

 which was put up in five-gallon tin cans. It is probable, 

 too, that the offal generally will all be used ultimately for 

 oil and manure. The prices so far realized for the salmon 



