142 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Lower down in tributary iiools and miry places were sticklebacks in abuudauce. iSTear 
its mouth one sculpin was seen. 
In this stream and in the others trout are occasionally taken and sometimes salmon 
enter them from the sea. Lopez Creek, a mountain tributary of Arroyo Grande, is the 
best-known trout stream in San Luis Obispo County. It is said by anglers that the 
brook trout exist in the mountains and the salmon trout come uji from the sea and 
‘‘promiscuously mix with it.” This seems another way of saying that the brook trout 
(irideiis) and the salmon trout {gairdneri) are but forms or states of the same fish. 
The individuals which run to the sea grow larger and are more silvery in color than 
those Avhicli remain in the brooks. 
The following is a list of the fishes of the streams of San Luis Obispo County so 
far as recorded : 
1. Agosia nubila (Girard). 
2. Salmo mykiss gairdneri (Richardson). 
3. Salmo mykiss irideus (Ayres). 
4. Oncorhynchus tschawytscha (Walbauiu). 
5. Gasterosteus microcephalus Girard. 
6. Cottus gulosus (Girard). 
7. Eucyclogobius iiewberrii (Girard). 
In no other stream of the United States in which an equal amount of water fiows 
has so short a list been recorded. 
