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

6.0 Riprap Biota
6.0 RIPRAP BIOTA
6.1 INTRODUCTION
Riprap biota occupies much of the shoreline
in Los Angeles and Long Beach harbors.
Riprap habitat is generally comprised of
boulders found at the outer breakwaters and
along the shoreline of many of the basins
and channels. Pilings that support wharves
and piers throughout the harbors and
concrete debris also provide hard-bottom
substrate for riprap communities. Riprap
habitat extends from the upper tidal zone
(intertidal) to the subtidal zone.
Several historical studies have described
riprap biota in the harbors. MBC (1984)
described community structure, recovery,
and trophic interactions of riprap habitats in
Long Beach Harbor and Queensway Bay.
Previous baseline studies of riprap biota include MEC (1988) in Los Angeles Harbor and MEC
(2002) in both Los Angeles and Long Beach harbors. These studies characterized dominant
riprap organisms, measured physical conditions in riprap areas, and documented spatial and
temporal variability of riprap biota.
The objective of the Year 2008 baseline study was to provide an updated characterization of the
riprap community in Los Angeles and Long Beach harbors. Riprap associated invertebrates
and algae were surveyed over two seasons at the same four locations in each harbor evaluated
during the MEC (2002) study. Quadrats were sampled and biologist divers made general field
observations to describe commonly observed organisms. Methods used to survey the
community are described in Section 6.2. Ecological information on riprap biota in this report
includes community summary measures (Section 6.3), species composition (Section 6.4),
dominant species (Section 6.5), and spatial and temporal variation (Section 6.6). The survey
results are compared to historical data in Section 6.7. Exotic species considered nonindigenous
to the harbors are identified in Section 6.8. Raw data summaries are provided in
Appendix F.
6.2 METHODOLOGY
6.2.1 Diver Surveys
Riprap biota, including invertebrates and
algae, were sampled in January (winter)
and August (summer). Four locations
were surveyed in each harbor for a total
of eight stations (Figure 6.2-1). Stations
were identified by harbor unique number
(e.g., LARR1 = Los Angeles riprap Station
1). Representative photographs showing
typical habitat and biological resources
were taken at each location. Some of the
2008 Biological Surveys of Los Angeles and Long Beach Harbors 6–1
April 2010