were located at 1-m intervals to a maximum depth of -2.0 m. Sampling at 
all levels involved both line-transect and photographed-quadrat census 
techniques. Motile macroinvertebrates were also sampled at +l-m, MLW, 
-l-m, and -2-m levels at stations where water depths were sufficient to use 
a quantitative suction sampler. A more limited effort was made to assess 
fish. Sampling techniques included collections by gill nets, traps, 
seine net, hook and line and observations by scuba divers. Fish stomachs 
were also collected for diet analysis, and hydrographic samples were 
collected during every sampling period. 
4. Water temperature, salinity, clarity, and dissolved oxygen reflected 
the expected hydrographic patterns in the area. Temperatures ranged 
from 5.89 - 30.3°C, salinity from 34.5 - 36.1 °/oo0, dissolved oxygen was 
almost always near saturation, and water clarity varied from 0.7 to 2.5 m. 
5. Results of the biological assessments indicated that a diverse 
assemblage of fauna and flora had colonized both jetties. At least 
25 algal species, 195 macroinvertebrate species, and 34 fish species 
were found over the four-year study period. 
6. Coverage by sessile biota was generally as great one year after 
construction as in subsequent years. This was primarily due to the early 
settling of blue-green algae and barnacles in the intertidal zone and 
mussels in the subtidal zone. Biota cover was generally higher in the 
lower intertidal and subtidal zones than in the upper intertidal zone, 
which represented a more rigorous physical environment. On the wave- 
exposed side, cover was often greater at higher levels than on the 
protected side. Other differences between sides were minimal, presumably 
because wave energy is moderate in this area. The number of sessile 
taxa found at the stations was as high after one year as in subsequent 
years. No differences were noted between sides in terms of the number 
of species, but more species were present subtidally than intertidally 
on all sides. 
7. Community structure of the sessile biota showed both seasonal and 
yearly variation on the jetties. Variation between sampling periods 
was less in the intertidal zone where there was distinct banding of 
blue-green algae and barnacles (Chthamalus fragilis) in the mid- to 
high-intertidal area, and mussels (Brachtdontes exustus), barnacles 
(Balanus spp.) and algae (primarily Ulva sp. and Hypnea musciformis) 
in the lower region. Temporal variability in the subtidal community 
was much greater, with dominance changing from mussel cover (B. exustus) 
to algal, bryozoan, hydroid, and ascidian cover, depending on the side 
of the jetty and the year. No evidence of a stable "climax" community 
was found by the end of the study period, with the possible exception 
of the intertidal biota as noted above. Furthermore, results from other 
studies suggest that a "climax" community is not likely to occur. 
Differences observed between sampling periods, and between sides of the 
jetties, were attributed to predation, competition, natural mortality 
and light penetration (see text for details). Wave action was not 
considered to be an important factor with regard to differences in 
species composition between sides. Although species composition was 
different, study results paralleled findings obtained in other rocky 
intertidal systems. 
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