2007 Annual Monitoring Report (pdf 16MB) - Bolsa Chica Lowlands ...

Bolsa Chica Lowlands Restoration Monitoring2007 Annual ReportThe water quality conditions observed in the FTB during this first quarter of monitoring show the tidalmarine influence that now exists in the basin, reflecting the daily and monthly tidal fluctuations seen inthe open ocean. All parameters were well within acceptable ranges to support the developing fish,invertebrate, and vegetation communities, and are indicative of a well-flushed marine environment.No changes are recommended to the water quality monitoring program at this time.VEGETATION/HABITATThe distribution, composition, and evolution of vegetation communities and unvegetated habitats arebeing monitored through the use of aerial photography and quantitative transect methods. The January2007 assessment of habitats at Bolsa Chica mapped eight vegetated and seven non-vegetated habitatswithin the 402-hectare (994-acre) study area. Vegetated habitats included: southern coastal salt marsh,disturbed coastal salt marsh, mule fat scrub, coastal sage scrub, freshwater marsh, southern arroyowillow riparian forest, decaying/transitional vegetation, and non-native vegetation. Non-vegetatedhabitats included: salt panne, disturbed salt panne, intertidal sand shoal, intertidal mudflat, open water,unvegetated nest site, and urban/developed.Cordgrass and eelgrass were transplanted throughout the FTB in August 2007. The cordgrass isanticipated to establish on the broad intertidal mudflats on the eastern shore to the FTB while eelgrassis expected to colonize much of the subtidal areas of the FTB. If patterns of expansion follow thoseobserved in other large-scale restorations, the ultimate expansion from the introduced patches isexpected to be slow at first with much more rapid expansion both vegetatively and through seedlingrecruitment around the third year following initial tidal restoration.The present vegetation monitoring has been used to establish a baseline. The first full vegetationmonitoring event, including aerial photography, habitat mapping, transect surveys, and soil analysis,will be conducted in summer 2008 (Year 2) as called for in the Monitoring Plan.Continued collection of aerial imagery each year (rather than in Years 2, 5, and 10 only) isrecommended, to track changes in water levels, site conditions, and habitat development over time.FISH COMMUNITYFish community sampling was initiated in monitoring Year 2 with the first sampling occurring inOctober 2007. Sampling was performed during daylight hours at three stations: Stations 1 (furthestfrom the ocean) and 2 (closest to the ocean) in the FTB, and one in the Muted Pocket Marsh (MPM).Sampling equipment used included an otter trawl, purse seine, and beach seine in the FTB and a beachseine only in the MPM. Captured fish were identified, counted, measured, and weighed. Physicalwater quality parameters were measured coincident with the fish sampling efforts.A total of 4,426 individual fish were captured in October 2007. The catch represented 18 species offish, from 14 families. At Station 1, a total of 2,185 fish, represented by 15 species, were captured.The mean density across gear types at Station 1 was 0.52 individuals/m 2 . Topsmelt (Atherinopsaffinis) and juvenile anchovy (Anchoa sp.) comprised 95% of the fish captured. At Station 2,considerably fewer fish were captured, with a total of 845 fish represented by 12 species. The meandensity across gear types at Station 2 was 0.19 individuals/m 2 . Topsmelt were again the most abundantfish, accounting for 92% of the total catch. Only three species were captured in the MPM: topsmelt,Merkel & Associates, Inc. 2