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

1.0 Introduction
Historical comparisons among studies can be difficult due to factors such as changes to the
configuration of the harbors, creation of shallow water habitats, and differences in sampling
methodologies among studies. For example, early studies by MBC (EQA-MBC 1978) provide
data summaries across stations but do not include station-specific data, while more recent
studies such as MBC (1984), MEC (1988, 1997, 2002), SAIC and MEC (1997), and City of Los
Angeles (CLAEMD 2000) provide data tables by station that facilitate comparisons with data
from the present study. This study is most comparable to the previous baseline study (MEC
2002) based on sampling site locations, methodologies, and data analyses. Comparisons to
other previous biological studies are presented in each Chapter but are focused more on
comparisons with the previous baseline study by MEC (2002) than with other earlier studies that
may have limited overlap in methodologies and analyses. Historical comparisons are presented
toward the end of each Chapter.
Because some of the historical ichthyoplankton studies have used non-standardized sampling
methods, a special study was conducted to address differences between these nonstandardized
(most recent baseline methods) and more standardized methods being used by a
wide variety of agencies and organizations. The non-standardized methods used in previous
baseline studies differ somewhat from the standardized, common methods used by the
California Cooperative Oceanic Fisheries Investigations (CalCOFI), an organization that collects
quarterly hydrographic and biological data off southern and central California (Smith and
Richardson 1977) and power plant entrainment studies conducted throughout California
(Steinbeck et al. 2007). The methods used by CalCOFI and the power plant studies are
approved by the State Water Resources Control Board (SWRCB), California Energy
Commission (CEC), and the California Coastal Commission, and consist of using oblique tows
(referred to as the “CalCOFI method”) to evenly sample the entire water column as opposed to
using different nets to discretely sample different parts of the water column. A detailed
discussion of this methodology is presented in Chapter 4.
To evaluate whether the two methods resulted in comparable or different data, a special study
was conducted to compare larval composition and density collected by the present method used
for the Ports during previous baseline studies and the CalCOFI method. Detailed results of this
special study, including method recommendations for subsequent baseline studies conducted
by the Ports are presented in Chapter 4 (Ichthyoplankton) of this report.
Another special study was conducted, to compare results from benthic sampling using a box
corer with sampling using a Van Veen grab. Generally, the Van Veen provides a sample with a
greater surface area (0.1 square meters [m 2] ) than a box core (0.06 m 2 ), as noted in the 2000
biological baseline study (MEC 2002) and several previous baseline studies. Other coring
devices with a sampling area of 0.1 m 2 have been used for some historical harbor studies (MBC
1984) and City of Los Angeles monitoring. While species composition generally has been
shown by these studies to be similar among box core and Van Veen samplers, the numbers of
individuals per sample typically increase with increasing surface area sampled. Generally, that
difference is adjusted by standardizing count data (e.g., to 0.1 m 2 ). There also may be some
differences in species composition in habitats where species have a patchy distribution. This
special study was designed to compare results from both sampling devices to evaluate any
significant differences in abundance estimates, species number, and species composition.
Method differences were also evaluated in the context of project effort (e.g., sample processing
time). Detailed results of this special study are presented in Chapter 5 (Benthic and Epibenthic
Invertebrates) of this report.
2008 Biological Surveys of Los Angeles and Long Beach Harbors 1–5
April 2010