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

4.0 Ichthyoplankton
The results of the RELATE analysis showed that the rank correlation for all nineteen stations
had a calculated probability level of 63 percent (i.e., the value exceeded 63 percent of the
correlations calculated from the random permutations of the data). The probability level
increased to 89.5 percent when the analysis was conducted only on the data from the ten Los
Angeles Harbor stations. Although not significant at the 95 percent level usually employed in
statistical testing, the results are consistent with the MDS depiction of the relationships among
those stations showing a relationship between the location of the stations and the associated
suite of larval taxa.
4.4 HISTORICAL COMPARISON
A comparison between the 2000
(MEC 2002) and current study results
shows a generally similar composition
of the larval fish. The six most
abundant larval fish taxa did differ
between the two studies in terms of
their percent abundance (Table 4.4-1).
Some of the differences might be due
to the current study only sampling
three quarters while the 2000 study
sampled during all four quarters of the
year. However, more larval taxa were
reported in the current study than in
the previous baseline study (MEC
2002), which was due to the presence
of only one or two individuals of a
number of taxa in the current study.
The percent of CIQ gobies and combtooth blennies was greater in the 2008 study than in the
previous baseline study while the percent of northern anchovies, clingfish, and queenfish was
lower during the current study than found in the previous study (MEC 2002). These differences
are not particularly dramatic: it is not unusual to observe differences in larval abundance
between years due to variations in the annual reproductive output of adult fish as a result of
variations in local environmental and biological conditions.
A direct comparison of the numerical abundance of the total larvae in the current study with the
2000 study is difficult because of discrepancies in data presentation in the earlier study. But in
general, their reported summary values are higher than both the numbers observed in the
current study and values reported in recent ichthyoplankton studies conducted in or near the
LA/LB Harbor complex (Harbor Generating Station [MBC et al 2007a], Haynes Generating
Station [MBC et al 2007b] and Alamitos Generating Station [MBC and Tenera 2007]).
Even though there were differences observed between the current study and the 2000 study,
the overall larval fish composition of both is similar to the earlier studies in the Ports (HEP 1976
and 1979, Brewer 1983, MBC 1984, MEC 1988 and 2002) and in recent entrainment studies in
the nearby vicinity (MBC et al. 2007a, MBC et al. 2007b and MBC and Tenera 2007). The
actual abundance of each larval taxon will vary based on the reproductive success of the adults
that live in or near the Port waters. The dominant groups during the most recent two studies
(MEC 1998 and 2002) and the current study were gobies, small fish whose adults live in and on
soft sediments that are present in large amounts in the harbor complex. Larval combtooth
blennies were also abundant in the recent studies; their adults are found living on pier pilings
that are abundant in the harbor complex.
4–6 2008 Biological Surveys of Los Angeles and Long Beach Harbors
April 2010