ACCLIMATIZATION OF FISH IN THE PACIFIC STATES. 
465 
Some remarks of Mr. Townsend on this point will be quoted. His complete 
report should be consulted by those desiring to fully investigate the matter: 
The interesting fact that oysters do propagate in San Francisco Bay, in certain favorable localities 
at least, calls for some explanation as to the long acceptance by the public of the statement that 
there has been no natural increase. * * * During occasional visits to the oyster beds in 1889, I 
found proof of considerable natural propagation of the eastern oyster in the southern part of San 
Francisco Bay, and transmitted evidence of the same to the United States Commissioner of Fish and 
Fisheries, who directed that an examination be made in order to determine to what extent this had 
taken place. * * * The investigations of this subject have simply disclosed the facts that the 
oyster has to some extent adapted itself to the new habitat iu common with the other introduced 
species, and that in spite of many unfavorable conditions it is slowly increasing. 
* * * vf * # * 
Not only are the chances for the fixing of spat diminished by the use of ground in some places 
where there are very few old shells upon the bottom, but almost all of the shells of Oatrea virginica 
are returned from the marketuien to the principal oyster company, who sell them for the manufacture 
of lime instead of using them for the improvement of the beds. These shells of eastern oysters, if 
returned to the beds where they were grown, or to other portions of the bay, would certainly increase 
the chances for the fixation of spat set free from the beds where adult oysters are growing. It is 
probable that careful attention to this matter of increasing the fixing surface required by the young 
oyster might make just the difference between rapid self-propagation and the present slow increase. 
One of the first indications I had of the natural propagation of the oyster was the finding of 
young oysters six months or a year old upon beds where those three or four years old were kept. 
They were in most instances attached to clusters of dead shells of the small native oyster. Very few 
were to be found .attached to adult specimens of Oatrea virginica, but this may be explained by the 
fact that such oysters are frequently handled and “laid out” to keep them well upon the surface and 
prevent any settling iu the mud. The handling is done in order to select and clean the largest for 
market, tho others being also cleaned of the ever-accumulating native oysters, which would involve 
the destruction of such small eastern oysters as might be among them upon the shells of the large 
oysters. 
The fact of young eastern oysters being attached to anything is proof that they grew in the bay 
where they were found, for oysters do not have the power of fixing themselves a second time. All 
these small oysters are knocked off the large shells with a small cleaning hatchet, and the operation 
is a necessary one, as the extremely productive natives cluster upon the larger species in such numbers 
as to greatly interfere with their growth. 
In October, 1891, I discovered some oysters of large size in certain sloughs of the south bay, 
where they had long escaped the stingrays in consequence of bars which shut off the sloughs from all 
but the highest tide. These were the largest oysters ever seen at San Francisco, and had evidently lain 
there for several years. More recently I obtained a quantity of oysters, apparently two years old, in 
Oakland Creek. As the oyster beds maintained there several years ago by Mr. Doane, now of the 
Morgan Oyster Company, have long since been abandoned and the stakes removed, it is evident that 
a limited number of oysters have found conditions suitable for their development and growth, even 
in this muddy place. They are no longer found on the mud flats, where they were originally kept, but 
live in the mud of the channel, from which I obtained them with tongs. 
Mr. Cleaveland Forbes, of the Spring Valley Water Company, informed me that several years 
ago he found full-grown eastern oysters upon the piles of an old narrow-gauge railroad trestle, across 
a slough, near Dumbarton Point, and that the men of his party frequently found many upon banks 
composed of shells of the native species, near where the pipes of the company cross the bay. 
Mr. H. D. Dunn has recently reported, through the press, the discovery of a full-grown eastern 
oyster near Mile Rock, in the Golden Gate. 
It is possible that during the long time eastern oysters have been kept iu the bay they have 
become in a measure acclimated, and that there is a constantly increasing tendency to propagate — 
that is, the progeny of oysters grown here become hardier with each generation and better adapted 
to the colder but more equable waters. 
During my latest examinations of the bay (May and June, 1891) eastern oysters, very large and 
old, were found iu the following places near the sites of former oyster beds: Several adhering to the 
piles of the narrow-gauge railroad trestle across San Leandro Bay ; a few upon the rocks at the > extreme 
F. C. B. 1895—30 
