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

3.0 Adult and Juvenile Fishes
samples (Figure 3.3-2). The significantly higher biomass during the summer was primarily due
to large catches of northern anchovy and large-sized species such as bat rays.
Similar to the patterns for abundance and biomass, the number of species collected was greater
at night (19 species) than during the day (12 species; Table 3.3-1). In addition, the number of
species generally increased from fewer species collected in winter to the greatest number of
species collected in spring and summer. More species were collected at Station LA7 (15) for
day and night sampling combined than at any other station (Table 3.3-2). The fewest number of
species (3) was collected at Stations LA1, LA4, and LB4. In general, more species were
collected at the shallow-water stations than at the other stations.
3.3.4 Historical Comparisons
Although gear differences can account for differences in sampling results from study to study,
overall patterns in common and abundant species collected in the harbors have remained
similar. Fish studies in the 1970s primarily used gill nets, rather than lampara nets, to
characterize pelagic fish communities. However, historic gill net catches were dominated by
both pelagic and demersal species, including white croaker, northern anchovy, shiner surfperch,
queenfish, white surfperch, and walleye surfperch (Horn and Allen 1981). Since the late 1980s,
pelagic fish populations have been sampled occasionally using lampara nets, with periodic
surveys in Los Angeles (MEC 1988, 1999) and Long Beach (MBC 1990; SAIC and MEC 1996)
Harbors and Queensway Bay (MBC 1990).
Northern anchovy, Pacific sardine, white croaker, queenfish, and California grunion were most
abundant in lampara samples during 1986-1987 (MEC 1988). Similarly, northern anchovy,
Pacific sardine, white croaker, queenfish, and topsmelt or Pacific butterfish were most abundant
in lampara samples during the 1990s (MBC 1990; SAIC and MEC 1996). The same fish
species were most abundant in lampara samples during the previous baseline study in 2000
(MEC 2002), with lower abundances of Pacific sardine compared to the 1980s and 1990s.
In contrast to seasonal trends observed in previous studies (MEC 1988; SAIC and MEC 1996),
specifically for abundance and number of species, no clear seasonal patterns in the pelagic fish
community were evident during the current study. This is likely due to highly variable catches of
the most dominant pelagic fishes during each survey and may also have been influenced by
sampling conducted over three quarters compared to four.
Temporal patterns in biomass were observed. Similar to abundance and number of species,
biomass values varied but were higher during the summer (July) survey. While some previous
studies indicated shallow-water stations had generally lower abundances, but higher biomass
and number of species compared to deepwater stations (MEC 2002), the current study found
that shallow-water stations such as LA7 in the outer harbor had some of the highest
abundances of any station sampled in 2008. As was the case in previous studies in which day
and night samples were collected (MEC 1996; SAIC and MEC 1996; MEC 2002), more species
in greater numbers were collected at night in the current study. Day/night differences in catch
are likely due to a combination of fish behavior (decreased ability to detect and avoid sampling
gear at night), increased dispersal of schooling species, and increased foraging activity at night
(Horn and Allen 1981).
Inner and outer harbor differences in species composition of pelagic fish were documented
during an earlier study of Los Angeles Harbor by MEC (1988). The MEC (2002) study also
found outer harbor assemblages generally had relatively higher abundances that were
distributed among more species (higher diversity) than those in the middle and inner harbor
areas. In contrast, the current study did not find similar habitat associations or distributions of
pelagic species. Most pelagic fish species in this study had more “harbor-wide” distributions
2008 Biological Surveys of Los Angeles and Long Beach Harbors 3–7
April 2010