On the Life History of Nereis grubei (Kinberg), a Polychaete 
Annelid from California 1 
Paul C. Schroeder 2 
Relatively little information is yet avail- 
able on the life histories of nereid polychaetes 
from the eastern Pacific. Johnson (1943) has 
raised some intriguing problems concerning 
Nereis vexillosa , which have not been further 
explored, and Smith (1950) has reported de- 
tails of the life history of Nereis limnicola 
(= Neanthes lighti ), an interesting viviparous, 
euryhaline species. Information is also available 
for a southern Californian population of Nereis 
grubei , a species which reproduces more typi- 
cally. The present paper deals with a central 
Californian population of N. grubei from Pes- 
cadero Point, Monterey County. Interesting dif- 
ferences between these two populations with 
respect to physiology and breeding season have 
come to light during the course of an investiga- 
tion of nereid metamorphosis (Schroeder, 
1967). 
HABITAT 
At Pescadero Point, Monterey County, Cali- 
fornia, Nereis grubei occurs on an exposed 
coast where the surf can be quite violent, even 
though offshore kelp beds are well developed. 
The intertidal region is composed chiefly of 
large boulders covered with abundant algae of 
many species. The worms may be found here in 
two different situations, in which their abun- 
dance varies with the season. During the spring 
and summer they are most readily found in the 
sandy substrate beneath the common red alga 
Gastroclonium coulteri. Some specimens may be 
found in this situation throughout the year, but 
from the beginning of October until the middle 
1 A portion of a dissertation submitted to the 
Graduate Division of Stanford University in partial 
fulfillment of the requirements for the degree of 
Doctor of Philosophy. Manuscript received Septem- 
ber 26, 1967. 
2 Hopkins Marine Station, Pacific Grove, California. 
Present address: Department of Zoology, Washington 
State University, Pullman, Washington 99163. 
of February the animals are more abundant in 
holdfasts of the highest specimens of the brown 
kelp Egregia menziesii. In order to collect the 
animals from their burrows in the kelp the 
holdfasts must be removed from the rock with 
a hammer and chisel and carefully dismembered. 
During the summer only a few, usually very 
small specimens can be recovered from these 
holdfasts; this was tested by allowing summer- 
collected holdfasts to stagnate in a pan until 
animals emerged from the inaccessible inter- 
stices. It seems probable that the worms move 
into the kelp holdfasts for the winter, when the 
surf is most violent. Such seasonal habitat shifts 
are known in other intertidal animals from this 
area as well (e.g., the isopod Idothea monterey- 
ensis [see Lee, 1966]). 
The habitat reported by Reish (1954£) for 
the species at Point Fermin in southern Califor- 
nia appears to be somewhat different. He found 
N. grubei in algal tufts in or between tidepools 
scoured from a wide, flat rock ledge. The ledge 
is strewn with scattered boulders and sheltered 
from the surf by offshore kelp beds. At Point 
Fermin the worm was found to be associated 
with a number of different species of algae, 
chief among which is Cladophora trichotoma. 
This alga occurs in central California as well, 
and a search through tufts of it near the Hop- 
kins Marine Station, not far from Pescadero 
Point, failed to yield any specimens of N. grubei , 
although the worm occurs beneath Gastroclo- 
nium in the same area. Although Reish surveyed 
the algal associates of the species at Point Fer- 
min he mentions neither Egregia menziesii nor 
Gastroclonium coulteri , the two major algal as- 
sociates at Pescadero Point. The former is not 
found south of Point Conception, but the latter 
is recorded from as far south as San Diego 
(Smith, 1944). It thus appears that the more 
northerly population favors Gastroclonium , de- 
spite the presence of Cladophora , and that the 
opposite is true for the southern population 
476 
