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

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Topsmelt January April July October Slough Anchovy 18 16 14 12 10 8 6 4 January April July October Number of individuals 2 20-29 30-39 40-49 50-59 60-69 70-79 80-89 90-99 0 40-49 50-59 60-69 70-79 80-89 90-99 100-109 110-119 120-129 130-139 140-149 150-159 Size Class (mm) California Killifish 70 60 50 40 30 20 10 January April July October Number of individuals 10-19 20-29 0 30-39 40-49 50-59 60-69 70-79 100 90 80 70 60 50 40 30 20 10 0 Size Class (mm) Kelp Bass January April July October 50-59 60-69 70-79 80-89 90-99 100-109 110-119 120-129 130-139 140-149 200-209 210-219 Size Class (mm) Size class distribution of topsmelt, slough anchovy, kelp bass, and California killifish in the Full Tidal Basin in 2008 Standard length (mm) Bolsa Chica Lowlands Restoration Project Figure 1-10 Merkel & Associates, Inc. 40-49 30-39 30-39 20-29 20-29 10-19 10-19 14 12 10 8 6 4 2 0 Size Class (mm) Number of individuals Number of individuals
Bolsa Chica Lowlands Restoration Monitoring 2008 Annual Report Discussion The 2008 monitoring year included the period of 17 to 25 months post-opening to the ocean. During the first survey in October 2007 (13 months post-opening), a total of 17 species were observed in the FTB (Merkel & Associates 2008). By October 2008, the cumulative total had increased to 38 species after 5 surveys (though only 15 species were captured in the October 2008 survey itself). The only species captured in the FTB in 2007 but not 2008 were snubnose pipefish, California tonguefish, and striped mullet. The pipefish and tonguefish may still be present but undetected and striped mullet were frequently seen, just not captured due to the difficulty of catching them without a gill net. The species joining the fish community in the FTB are increasingly associated with structured habitats, which is most likely due to the spread of eelgrass habitat, particularly in the southern half of the basin. Structure-associated fish such as blennies, surfperch, and kelpfish will likely increase in abundance as eelgrass continues to spread in the coming years. The eelgrass also provides nursery habitat for species such as topsmelt, which lay eggs on the eelgrass in estuaries and bays (Emmett et al. 1991). The creation of the FTB has increased the availability of important bay habitat, provided nursery functions for many species of marine fish, and thereby improved southern California fisheries resources. Nearly every fish species captured during the 2007 and 2008 monitoring was represented by juvenile size classes, demonstrating the linkages between the basin and coastal fisheries, and the role of the basin as nursery habitat for spawning or post-larval dispersal. CDFG staff have also reported spawning by California grunion on the high sand beach on the north side of the channel entrance (K. O’Reilly pers. comm.). The creation of shallow-water habitat rich with primary production supplies detritus-based and grazing-based food webs with energy. Ultimately, this energy is transferred to fish and used to support increased biomass and numbers. Additionally, this increased production is transferred offshore with individuals that leave the basin, or it supports other ecological communities through consumption by avian and mammalian consumers. The fish community of the MTBs was in its early stages in 2008, with only the western basin open to tidal influence and manual adjustments still being made to its tidal range throughout the year. The presence of high numbers of topsmelt and California killifish are reflected in the usage of these basins by terns and wading marsh birds for foraging. The large numbers of post-larval atherinids captured in July suggests the basin is being used for spawning. Although the west MTB showed relatively stable water quality, the central and east will continue to experience fluctuations in temperature, salinity, and dissolved oxygen that will limit the diversity of fish that can persist there. It is anticipated that diversity and distribution of fish will increase once all three basins are opened directly to the FTB through their tide gates, allowing for more stable water quality, regular tidal flushing, and exchange of fish between the basins. The Muted Pocket Marsh continued to provide an abundant food source of small fish for the many piscivorous birds that use the marsh. It is key to note that the MPM is not hydrologically connected to the FTB of Bolsa Chica, rather it receives muted tidal influence through a water control structure from outer Bolsa Bay, through Huntington Harbour, which ultimately opens to the ocean over 6.5 km (4 miles) to the northwest. It is anticipated that future sampling events may reveal a few more species tolerant of lower salinities and limited tidal flushing, however the muted tidal conditions, the water control structure, and the distance from the ocean will likely limit the diversity and size of fish that ultimately make up the community of the marsh. Merkel & Associates, Inc. 54
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Total Future Full Tidal Basin FFTB
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Western Snowy Plover Nesting at Bol
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2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

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