Habitat
Codium
setchellii occurs on exposed substrates in the low intertidal
zone. This species seems to prefer large rock substrate. The literature
seems to suggest C. setchellii is often found on vertical
faces (Abbott
and Hollenberg 1976). There have been records of the species in
crevices (Doty 1947, Sanborn
and Doty 1947, Markham and Celestino
1977). C. setchellii seems to favor sites with moderate exposure
to waves (Scagel 1957, Scagel
1966, Scagel 1973, Hawkes
et al. 1973). Additionally, populations in Oregon waters are found
areas of sand scour, but are scarce in these habitats; they appear
to be in a delicate balance given the potential for tissue damage
by extreme sand scour, but their slow growth rate and long lifespan
allow them to persist in these conditions (Trowbridge
1996).
C.
setchellii Habitat Characterization in the Monterey
Bay
Observations
of C. setchellii for the distribution mapping were also surveyed
for habitat preference for C. setchellii occurrence. From
the distribution mapping, it is believed that C. setchellii only
occurs in areas of moderate wave exposure. The species was
not observed inside Monterey Bay proper, where wave exposure was low
(so-called wave-protected environments), suggesting C. setchellii
favors areas with wave action. This would not be unusual, as areas
of increased wave activity also provide higher levels of nutrients,
due to mixing in the currents. [Another consideration is whether wave
exposure limits a competitor or herbivores.]
In
general, C. setchellii was most often found on vertical faces,
often with significant slopes. There were some instances (primarily
among individuals sampled from Point Pinos, Pacific Grove, CA) where
the alga occurred on horizontal rock faces. It typically occurs on bedrock
or large boulders, and seems to be absent on small boulders (at least
in the sites sampled).

Figure 1: Codium setchellii colonies
on vertical rock faces at Point Pinos (Pacific Grove, CA, USA)

Figure 2: An individual C. setchellii occurring on the horizontal
surface of a rock at Point Pinos (Pacific Grove, CA, USA)
The
largest occurrence of Codium setchellii on the Monterey Peninsula
was found in Carmel (CA, USA). Here, C. setchellii formed a
crust that covered large percentages of the rocks in the intertidal
zone. The alga primarily occurred on vertical or near-vertical rock
faces. Some were observed on the horizontal face of the rocks. Only
rarely were specimens observed on the underside of rocks or in crevices.

Figure 3: Vertical face with cover of Codium setchellii
crust at Carmel site
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