2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...
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<strong>Bolsa</strong> <strong>Chica</strong> Lowlands Restoration <strong>Monitoring</strong><br />
<strong>2008</strong> <strong>Annual</strong> <strong>Report</strong><br />
Recommendations<br />
No changes to the fisheries monitoring program are recommended at this time. The next monitoring is<br />
scheduled to occur in Year 5, with sampling events in October 2010, and January, April, and July<br />
2011.<br />
1.4. BENTHIC MONITORING<br />
Introduction<br />
The <strong>Monitoring</strong> Plan calls for benthic invertebrate monitoring to be initiated in Year 2 (October 2007<br />
to September <strong>2008</strong>) and to be repeated in Years 5 and 10 following the opening of the FTB to the<br />
ocean. The Year 2 sampling was conducted in January and July of <strong>2008</strong>. The objective of the benthic<br />
monitoring task in the <strong>Monitoring</strong> Plan is to characterize the marine invertebrate food resources<br />
available to birds and fish, as well as provide an index of general habitat quality in the basin.<br />
Methodology<br />
Infauna<br />
Three benthic sampling stations were established in the FTB: one along the north eastern shore, one<br />
along the western shore, and one in the southern portion of the basin (Figure 1-11). Three replicate<br />
collection points were established for each station. At each replicate point, a sediment core was<br />
collected from the + 0.3-m (+1-foot) NAVD elevation and from the -0.6-m (–2-foot) NAVD elevation.<br />
These elevations will be referred to in feet throughout this section. The elevations were estimated<br />
based on the water level compared to a known elevation at the east Water Control Structure in January<br />
<strong>2008</strong>. During the second sampling in July <strong>2008</strong>, the tidal range in the basin had been altered due to<br />
tidal muting caused by the accumulated flood shoal in the basin inlet, and the point of core collection<br />
had to be adjusted accordingly to best approximate the true tidal elevation.<br />
The sediment cores were collected using a 15-cm diameter corer inserted<br />
to a sediment depth of 15 cm, and rinsed through a 1.0-mm sieve. The<br />
sediment area sampled by each core was 0.018 m 2 . Core collection<br />
unavoidably captured the biota occurring on the surface of the sampled<br />
core, as well as in the water column for the –2-foot NAVD samples.<br />
Therefore, the collected samples could include epibenthic and open water<br />
organisms along with the infauna. Although captured fish were removed<br />
from the samples, all other organisms were retained and worked up along<br />
Sieving a sediment core.<br />
with the infauna. Organisms from each sample were placed in<br />
containers, preserved in a buffered 10% formalin:seawater solution, and transported to the laboratory<br />
for subsequent analysis.<br />
After approximately one week, organisms collected from the benthic cores were transferred in the<br />
laboratory into 70% isopropyl alcohol. All individuals in each replicate sample were identified to the<br />
lowest practical taxonomic level, counted, and the wet weight measured. Wet weight was determined<br />
by transferring the sample, including alcohol, onto a paper towel and blotting quickly to remove excess<br />
liquid from the animals. Organisms were then transferred to a tared weighing dish and weighed to the<br />
Merkel & Associates, Inc. 55