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

7.0 Kelp and Macroalgae
Overall, outer harbor transects were dominated by Macrocystis and Egregia (Table 7.4-1).
Macrocystis was present at all outer harbor sites, but was not observed along any inner harbor
transects. Egregia, a shallow subtidal to intertidal alga, was present at eight of twelve outer
harbor sites. This species generally occupied relatively shallow water habitats while
Macrocystis was found in slightly deeper waters. Understory species such as the coralline red
algae Corallina spp. and the brown algae Dictyota and Colpomenia were also common in outer
harbor habitats (Table 7.4-1). The invasive brown algae Sargassum muticum and Undaria were
found at ten of the twelve and seven of twelve outer harbor sites, respectively (see Section 7.6).
7.5 HISTORICAL COMPARISONS
Giant kelp, Macrocystis pyrifera, has a relatively short history within the Ports of Los Angeles
and Long Beach. Port habitats supported little Macrocystis until transplantation efforts in 1977
(Rice 1983). Spatial distribution data for Macrocystis in the Ports prior to the 2000 baseline
study is limited. Some kelp surface canopy coverage data is available from aerial surveys
performed in 1989 by the California Department of Fish and Game (CDFG), but the data set is
limited to small areas adjacent to the outer breakwater. MEC (1988) studied the fauna of the
kelp forest along the breakwater near the current station T2, but did not map kelp elsewhere in
the harbor complex. Anecdotal data suggests that kelp abundance in the Ports has increased
significantly since 1977 and that relative densities have fluctuated in tandem with coastal
populations at Palos Verdes (MEC 1988). Regional kelp abundance has only recently started to
recover from significant die offs attributed to El Niño events in the 1980s and 1990s.
Comparisons of CDFG aerial surveys performed throughout California in1989, 1999, and 2002-
2006 found a noticeable increase in kelp surface canopy coverage within the Southern
California Bight during recent years.
Increases in giant kelp density are also due to increases in available habitat in the outer harbors
of the Ports through construction of additional jetties, riprap-supported piers, and the Cabrillo
Shallow Water Habitat. Assuming that portions of the historically described kelp beds located
along the outer breakwater are perennial and reproductive, they have likely contributed to the
development of kelp communities elsewhere in the Ports. Persistent kelp beds adjacent to the
outer breakwater, along with the expansion of kelp forests off the Palos Verdes Peninsula, likely
represent a consistent supply of sporophytes and gametophytes that can establish new kelp
communities in the Ports.
Scientific investigations of kelp forest habitats within the Ports have been limited to a kelp forest
productivity study (fauna only) performed by MEC in 1986-87 (MEC 1988) and the previous
2000 baseline study (MEC 2002). The 2000 baseline study was the first systematic effort to
quantify kelp surface canopy coverage throughout the Ports. The total mapped canopy cover of
Macrocystis in the spring of 2000 was 24.8 acres, which decreased to 14.2 acres in fall 2000.
During the present baseline study, the Macrocystis canopy totaled 77.8 acres in spring 2008
and decreased to 50.4 acres in the fall of 2008. Kelp die-off between winter and fall can explain
seasonal declines in kelp canopy cover for both the 2000 and 2008 studies. The 2000 baseline
study reported a 43% decrease in canopy cover between spring and fall surveys compared to
35% decrease in 2008. Total mapped canopy cover of Macrocystis in the spring of 2008 was
over 300% greater than reported in the spring of 2000, with kelp canopy cover being identified in
several new areas within the Ports.
New kelp beds in the Port of Los Angeles that were not noted during the 2000 survey included a
large, dense bed adjacent to the Fish Harbor entrance, kelp canopy cover associated with the
Cabrillo Shallow Water Habitat, and a bed east of the Angels Gate harbor entrance approaching
the Port of Long Beach. Within the Port of Long Beach, kelp canopy cover near the entrance to
the West Basin and along Pier J increased dramatically in the present study compared to the
2008 Biological Surveys of Los Angeles and Long Beach Harbors 7–7
April 2010