2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Table 1-11. Summary of fish mass (g) in the Muted Pocket Marsh in 2008.
Species January 2008 April 2008 July 2008 October 2008
California Killifish 0.9 28.2 364.5 57.4
Topsmelt 235.1 231.9 1,213.3 2,205.3
Staghorn Sculpin 0.1 46.6
Yellowfin Goby 1.6
Longjaw Mudsucker 46.0 169.2
Cheekspot Goby 3.3
Arrow/Shadow Goby complex 4.4 10.2 1.2
Diamond Turbot 1.3 26.8
Total Mass (g) 237.4 388.8 1,757.2 2,263.9
Area Sampled (m 2 ) 1,301 1,206 938 1,301
The water quality conditions at the time of each sampling in the Muted Pocket Marsh were presented
in Table 1-7. In January water temperature was lower than all other sites (7.9°C), then reached a high
of 30.9°C in July. This basin can experience wide fluctuations in temperature due to its shallow depth
and restricted circulation from Outer Bolsa Bay through the tide gates. The salinity was fairly stable,
ranging between 30.9 ppt in January and 36.5 ppt in July. Dissolved oxygen in the MPM ranged from
5.2 mg/L in October to 10.9 mg/L in July.
Fish Length
Of all 42 fish species captured, all but three were represented to some degree by juveniles. The three
species captured only as mature individuals were thornback (Platyrhinoidis triseriata), California
needlefish, and jacksmelt. The minimum and maximum standard length of each fish species is
presented in Table 1-12.
In Figure 1-10, the number of individuals in each standard length size class is presented by quarter, for
four species selected based on their numerical dominance, commercial importance, or importance as a
food source for birds. Only fish captured in the FTB in 2008 (Stations 1 and 2) are included. As
described in the methods section, standard length was not determined for individuals that were batch
weighed. Therefore, the size class distributions shown include only individually weighed and
measured fish (the first 30 individuals of each species in each replicate) and therefore do not always
reflect the total catch of that species overall. Because the subsampling and batch weigh protocol was
designed to sample randomly across size classes, it is assumed that these data are generally
representative of total catch.
Topsmelt were generally smallest in July, with larger individuals present in April and October. July
also had the most small slough anchovy, consistent with Emmitt et al. (1991), which reports spawning
to occur from May to September, peaking in July. These smaller bait fish may have served as a food
source for nesting terns on the nest sites. Nearly all individuals of kelp bass, a recreational important
sport fish, were less than one year old based on their length (