appendix b final 2008 biological surveys of los angeles and long ...

7.0 Kelp and Macroalgae
7.4 MACROALGAE SPECIES COMPOSITION
Although giant kelp was found only in the outer harbor, other macroalgae species occur
throughout the Los Angeles-Long Beach harbor complex. The variability and complexity of the
subtidal environments present within the Ports of Los Angeles and Long Beach are reflected in
variable species composition and algal communities that are most accurately compared
between surveys of similar habitats and exposures, such as comparisons among inner harbor
stations or among outer harbor stations. Additional information for each transect is presented in
Appendix G.
7.4.1 Inner Harbor
Inner harbor stations typically experience
reduced tidal flushing, decreased wave
surge and currents, increased water
temperatures and sedimentation, and lower
dissolved oxygen levels compared to the
outer harbor (MEC 2002). Restrictions in
circulation tend to exclude the highly
productive, habitat-forming kelp and
macroalgae species such as Egregia and
Macrocystis, but other macroalgae are
tolerant of inner harbor conditions. Divers
swimming transects at inner harbor
locations (T7, T8, T10, T11, T12, T13, T18,
and T19) found between five and eleven
common species at each transect,
including Sargassum, Ulva, Colpomenia, Chondracnathus, and Halymenia (Table 7.4-1). The
invasive brown algal species Sargassum (also see Section 7.6) was present at all stations
except T7, typically growing in dense bands along the entire transect. Colpomenia and Ulva
were also present on transects at all inner harbor study sites. The greatest number of common
macroalgal species at inner harbor sites was at Transect T10 in the Los Angeles Turning Basin
near Berth 170, with eleven common species. The lowest diversity was observed at Transect
T7 in the Port of Long Beach near Pier C, which had patchy areas of only five macroalgal
species (Table 7.4-1). The only other species consistently present along inner harbor transects
was the invasive species Undaria (see Section 7.6).
7.4.2 Outer Harbor
Algal diversity at outer harbor sites was generally similar to that at inner harbor stations, with the
greatest observed diversity (11 common species) occurring at Transect T15 along the outer part
of Pier T (near the SeaLaunch facility) in the Port of Long Beach. Diversity was also high
(maximum of 10 species) on outer harbor transects T16, T17, and T20, all in the Port of Los
Angeles. The fewest number of outer harbor macroalgal species was the four species observed
on Transect T1, located on the outer breakwater in the Port of Long Beach. Although this
station had high abundances of herbivores, primarily the purple and red sea urchins
Strongylocentrotus purpuratus and S. franciscanus, a relatively healthy kelp (Macrocystis)
canopy persists at this location, with numerous plants surviving on isolated boulders surrounded
by small sand channels that likely are difficult for urchins to cross. Similar observations were
recorded at this location during the previous baseline survey (MEC 2002) and studies
conducted nearly 15 years earlier (1986-1987, as noted in MEC 1988).
7–6 2008 Biological Surveys of Los Angeles and Long Beach Harbors
April 2010