330 REPORT OF THE COMMISSIONER OF FISHERIES. 
southward so far that a fresh-water passage could easily be traced 
through a suecession of small ponds between it and Madera Creek. 
Shortly afterwards suckers ( Catostomus occidentalis) appeared in the 
latter creek, where they had not previously been seen, although the 
stream had been under observation for eight years. @ 
Not only is it apparent that the streams flowing into San Francisco 
Bay are intimately connected, but it is also probable that the basin 
as such is really a part of the great Sacramento-San Joaquin system. 
The only channel for communication with the latter is through the 
salt waters of San Pablo and Suisun bays. But conditions obtaining 
in this passage are greatly modified during periods of exceptional 
rainfall, when the drainage water from a large part of the state flows 
through it. It is possible that at such a time the salt-water barrier 
of the bays, though generally effective, may be broken down and an 
opportunity offered for the extensive migration of fresh-water fishes. 
Ayres? has shown that such migrations actually oceur. He records 
several fresh-water species as having been taken in various parts of 
the bay of San Francisco during the unusual floods of 1862. He also 
adds that snakes, even, were cast up alive on the beach. 
Thirteen species of fishes have been collected from the streams tribu- 
tary to San Francisco Bay. All are identical with forms found in the 
Sacramento and San Joaquin rivers, a careful comparison of specimens 
from the two basins having revealed no structual differences whatever. 
Four of these species, belonging respectively to the genera Lntosphe- 
nus, Salmo, Gasterosteus, and Cottus, are able to withstand salt water 
and may frequently pass out into the bay. The others are apparently 
able at certain times to pass between neighboring streams, and occa- 
sionally to take advantage of an open channel for migration between 
this basin and the Sacramento. 
The relation existing between species found in this basin and that 
of the Pajaro River to the southward remains to be discovered. The 
results of an examination of the coastwise creeks to the north of 
Monterey Bay will also be of great interest. 
a Madera Creek occasionally becomes so reduced in size during the dry season that its water might 
be held in a few barrels and its entire ichthic fauna easily placed in a pint cup. The presence of a 
species in such a stream could hardly escape an interested observer. 
b Ayres, Dr. W. O., Proceedings California Academy Natural Sciences, Vol, II, p. 163. (Feb. 3, 1862.) 
‘*For the last two months the fishermen who supply the markets of this city with fish have taken in 
the bay of San Francisco many fresh-water fishes, of species generally found in the rivers, not those 
inhabiting the smaller creeks. These have been caught at all the various points of the bay at which 
salt-water fishes only have previously been found. It is well known that the surface waters of the 
bay have been nearly fresh during these floods, and the fishes in question must have followed down 
and lived this length of time in the fresh surface water. They haye not been seen in the bay before 
this. The following species have been noticed: 
Arehoplites interruptus. Algansea formosa. 
Catostomus occidentalis. Lavinia compressa. 
Catostomus labiatus. Ptychocheilus grandis, 
Orthodon microlepidotus. Mylopharodon robustus.” 
Mr. Charles A. Vogelsang, chief deputy California Fish Commission, under date Jan. 24, 1905, 
writes: ‘‘There is no question but that at this season of the year suckers, catfish, carp, and black bass 
can be found in the waters of the bay on the Berkeley shore and on the east side of Angel Island.” 
