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

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
Muted Tidal Basins
The Muted Tidal Basins were sampled with the small beach
seine as described in the methods section above, with
variations in effort each quarter based on conditions within
each basin. The area and water depth sampled was highly
variable between quarters due to fluctuating water levels. In
some cases, unvegetated shoreline was not exposed to pull the
net up onto at the sampling site, so the net had to be lifted up
prior to shoreline vegetation, which reduced sampling of fish
right along the shoreline. Hauls were often filled with dead
plant debris from decaying pickleweed that was permanently
inundated by the introduction of tidal waters or heavy rainfall.
Beach seining the central MTB.
Six fish species were captured in the west MTB and seven in the central MTB (Table 1-8). Both arrow
and shadow gobies were captured in the west MTB. Topsmelt and juvenile atherinids were the most
common species in both basins. California killifish were abundant in October, and various gobies
were captured in all quarters. Both bay and barred pipefish were observed. Only one other barred
pipefish was captured in 2008 at Bolsa Chica (at Station 2 in the FTB). A small juvenile striped mullet
was captured in the far east end of the west muted tidal basin. In 2008 the central MTB was not
directly open to the FTB for any length of time, just periodically for a few minutes or up to one day.
Table 1-8. Summary of fish abundance (# of individuals) in the Muted Tidal Basins in 2008.
April 2008
July 2008 October 2008
Species West MTB Central MTB West MTB Central MTB West MTB
California Killifish 14 68
Topsmelt 2 76 26 168 301
Atherinid, unidentified juvenile 120
Bay Pipefish 1
Barred Pipefish 1
Staghorn Sculpin 3
Striped Mullet 1
Lonjaw Mudsucker 1 2 5
Cheekspot Goby 12 3
Arrow/Shadow Goby complex 8 1
Total Abundance (individuals) 145 77 30 185 376
Area Sampled (m 2 ) 126 155 310 170 129
The water quality conditions at the time of each sampling were presented in Table 1-7. Salinity in the
west MTB was similar to or just slightly higher than the FTB in each quarter, while salinity in the
central MTB was considerable higher, measuring 54.4 ppt in July and from 78-78 ppt in October. Both
MTBs were notably warmer than the FTB in July and October, due to their shallow depth and more
limited circulation (particularly in the central MTB). Dissolved oxygen was lowest in the central MTB
in July (4.2 mg/L).
The mass of the fish captured is presented in Table 1-9. These data show that although gobies made up
only 4% of the total count, they represented over 16% of the total biomass, due primarily to the large
size of the longjaw mudsuckers (Gillichthys mirabilis) captured.
Merkel & Associates, Inc. 49