50 
PACIFIC SCIENCE, Vol. XV, January 1961 
Fig. 1. Areas of collection. 
Catalina Island. Pachygrapsus eras sipes were 
collected from a point in the west channel of 
the Los Angeles Harbor area designated as L.A. 
7, the mouth of the San Gabriel River at Ala- 
mitos Bay, White’s Point, Santa Catalina Is- 
land, Anacapa Island, and Morro Bay (Fig. 1). 
White’s Point, L.A. 7, and the mouth of the 
San Gabriel River at Alamitos Bay can be con- 
sidered polluted areas; while Morro Bay, Santa 
Catalina Island, San Clemente Island, and Ana- 
capa Island are surrounded by nonpolluted wa- 
ter. In the polluted areas both the nature and 
the degree of pollution vary. 
White’s Point is a sewer outfall area in which 
the pipes convey the treated sewage to a site 
6,716 ft. from the shore line. According to 
Stephenson and Grady (1956), oxygen defi- 
ciency at 6,000-8,000 ft. from the outfall varied 
from 10-30 per cent, at one time of measure- 
ment, to 0 per cent (or normal) at another 
time. It was reported, further, that ammonia 
content was not normal in any area within 
11.000 ft. of the outfall. Measurements taken at 
3.000 ft. from the outfall showed an increase of 
silicates and phosphates. Although dilution un- 
doubtedly occurs in the remaining 3,700 ft., it 
would not be safe to assume that the water in 
the intertidal area where the specimens were 
taken is of normal composition. 
The White’s Point area is divided at low 
tide into a northern cove and a southern cove 
by a narrow expanse of rock which extends out 
from shore for approximately 200 ft. A survey 
of the fauna of these two sections shows them 
to be quite different. On the southern side of 
the rocky projections were found scattered speci- 
mens of Haliotis cracherodii, an occasional Pach- 
ygrapsus crassipes, masses of the tubed worm, 
Phragmatopoma calif ornica, and specimens of 
the limpets Fissurella volcano and Acmaea lima- 
tula. Empty Olivella shells were also present in 
relatively large numbers. In sharp contrast to 
this paucity of forms and individuals was the 
fauna of the northern section. Here were noted 
specimens of Pis as ter ochraceus, Strongylocen- 
trotus purpuratus. S. franciscanus, Ophiothrix 
spiculata, Bulla gouldiana, Aplysia calif ornica. 
Octopus bimaculatus, Conus calif ornicus, Pagu- 
rus samuelis, in addition to those animals found 
on the southern side. This difference can be ex- 
plained by the fact that the sewer outfall opens 
offshore in a line with the rocky projection 
which separates the two sides. The current flows 
primarily from north to south carrying the 
polluted water in the direction of the southern 
section. 
The point designated as L.A. 7 is located in 
the west channel of Los Angeles Harbor. The 
term "L.A. 7’’ was given to this particular point 
in a pollution survey conducted in 1952 by the 
Los Angeles Regional Water Pollution Control 
Board, and has been retained in this study so 
that this site may be recognized and related to 
data taken from that point. Specimens of Pachy- 
grapsus crassipes tested were taken from the 
piling and floats at one of the small yacht har- 
bors in this area. The nature of the pollution 
at this point has been designated as primarily 
raw sewage from approximately 500 persons. 
Oxygen content of the water, measured at 
monthly intervals over a period of 3 years (1956 
through 1958), showed fluctuations from a low 
of 2.0 to a high of 8.2 parts per million. An 
ecological survey of the area shows the custom- 
ary wharf fauna of the southern California wa- 
ters. Anemones, the wharf mussel ( Mytilus 
edulis ) , tunicates both solitary and colonial, 
hydroids, barnacles, and colonial serpulid worms 
are attached in great abundance to the under- 
side of the wooden floats, while numerous sped- 
