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

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

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Bolsa Chica Lowlands Restoration Monitoring2007 Annual ReportCoincident Water Quality Data CollectionWater quality data collected during the purse seine and otter trawl sampling on October 16, 2007 areincluded in Table 1-5. These data reflect a snapshot within the full day during which fish werecollected. A broader picture of the water quality conditions during the month of October waspresented previously in Figure 1-2. Only salinity was recorded in the Muted Pocket Marsh: 26.1 ppt.Table 1-5. Water quality during fish sampling (October 16, 2007).ParameterStation 1Station 2Surface Bottom Surface BottomTime 14:10 14:15 15:13 15:15Temp (°C) 19.1 19.1 17.4 17.3DO (mg/L) 7.6 7.7 8.7 8.7Salinity (ppt) 33.1 33.1 32.8 32.8Turbidity (NTU) 4 12 4 3Depth (m) 0.1 2.0 0.1 2.1These parameters all fell well within normal ranges for enclosed bays and estuaries of southernCalifornia during fall months and were reflected by the marine fish or macroinvertebrate communitiessampled at this time.DiscussionIt is somewhat premature to interpret much from the single sampling event completed thus far. It isinteresting to review the October 1997 fish sampling data for the first monitoring for the BatiquitosLagoon Enhancement Project (Merkel & Associates, 2002). At that time the lagoon had been open tothe ocean for approximately 11 months, did not yet support the extensive eelgrass beds it does today,and was similar in depth and tidal influence to Bolsa Chica at two stations. In reviewing these data, itwas found that comparable stations at Batiquitos Lagoon (Stations 3 and Station 4) yielded similardiversity and abundance.Comparison of Station 1 at Bolsa Chica to a similar interior station at Batiquitos Lagoon reveals 13species at Bolsa Chica and 15 at Batiquitos, with much higher densities at Bolsa Chica than Batiquitos(a mean density of 0.51 individuals/m 2 and 0.09 individuals/m 2 at Bolsa Chica and Batiquitos,respectively, standardized for gear type and station). Comparison of Station 2 at Bolsa Chica to asimilar interior station at Batiquitos reveals 12 species at Bolsa Chica and 17 at Batiquitos, withslightly lower densities at Bolsa Chica than Batiquitos (a mean density of 0.19 individuals/m 2 and 0.28individuals/m 2 at Bolsa Chica and Batiquitos, respectively, standardized for gear type and station).This review indicates that the fish diversity and density at Bolsa Chica were similar at this early stageof site development to another restoration project.Merkel & Associates, Inc. 33

Bolsa Chica Lowlands Restoration Monitoring2007 Annual ReportThe present October 2007 survey of the FTB found a paucity of mature fish; the system was dominatedby first-year juvenile fish. This observation would tend to suggest that early colonization of the newcoastal embayment was primarily by larval and juvenile recruitment and rather than by adultimmigration. The eggs and larvae of many of the juvenile fish captured are typically found along theopen coast, moving into coastal embayments as juveniles, including California halibut, diamond turbot,kelp bass, and striped mullet (Cailliet, 2000; Emmett et al, 1991; Thomson, 1963). The presence ofsmall juvenile anchovy and atherinids, likely only several months old based on their length, suggestsactive spawning is occurring within the FTB in these species.It can be expected that fish community development will occur through delayed community structuringprocesses (competition, predation, etc.) following pulses in dominance by a few species that were wellrepresented in the pelagic larvae at the time the system became available. Subsequent monitoring willlikely further illuminate patterns of recruitment and fish community development within the basin.The development of eelgrass resources within the FTB will add egg substrate and habitat complexitythat will result in greater fish diversity.Only three species of fish were captured in the Muted Pocket Marsh in October 2007, the majority ofwhich were juvenile topsmelt. At the time of the sampling the water was a deep red, possiblyreflective of an algal bloom, and was lower in salinity than the FTB (26.1 ppt). It is key to note thatthe MPM is not hydrologically connected to the FTB of Bolsa Chica, rather it receives muted tidalinfluence through a water control structure from outer Bolsa Bay, through Huntington Harbour, whichultimately opens to the ocean over 6.5km (4 miles) to the northwest. It is anticipated that futuresampling events may reveal additional species tolerant of lower salinities and limited tidal flushing,however the muted tidal conditions, the water control structure, and the distance from the ocean willlikely limit the diversity and size the fish that ultimately make up the community of the marsh.RecommendationsIt is recommended that fisheries monitoring continue for more than the presently scheduled fourquarters. This will provide for a meaningful assessment of the development of the fish community, aswell as allow for fisheries monitoring in the Muted Tidal Basins, which have not been assessed yet dueto the delay in opening them to tidal influence. Extending the quarterly sampling through Year 3 willhelp to fill the data gap that would occur between the scheduled Year 2 and Year 5 fish sampling. Recommendation: extend fisheries monitoring into Year 3.1.5. BENTHIC MONITORINGThe Monitoring Plan does not call for benthic monitoring to be initiated until Year 2 of the monitoringprogram, in January and July. The first monitoring was conducted January 2008. Data will beincluded in the 2008 (second) annual report. It is recommended that considerable be given toextending the benthic monitoring past Year 2. Only limited understanding of the development of thebenthic community will be gained in the two sampling events scheduled for Year 2. Recommendation: Extend benthic monitoring into Year 3.Merkel & Associates, Inc. 34

<strong>Bolsa</strong> <strong>Chica</strong> <strong>Lowlands</strong> Restoration <strong>Monitoring</strong><strong>2007</strong> <strong>Annual</strong> <strong>Report</strong>Coincident Water Quality Data CollectionWater quality data collected during the purse seine and otter trawl sampling on October 16, <strong>2007</strong> areincluded in Table 1-5. These data reflect a snapshot within the full day during which fish werecollected. A broader picture of the water quality conditions during the month of October waspresented previously in Figure 1-2. Only salinity was recorded in the Muted Pocket Marsh: 26.1 ppt.Table 1-5. Water quality during fish sampling (October 16, <strong>2007</strong>).ParameterStation 1Station 2Surface Bottom Surface BottomTime 14:10 14:15 15:13 15:15Temp (°C) 19.1 19.1 17.4 17.3DO (mg/L) 7.6 7.7 8.7 8.7Salinity (ppt) 33.1 33.1 32.8 32.8Turbidity (NTU) 4 12 4 3Depth (m) 0.1 2.0 0.1 2.1These parameters all fell well within normal ranges for enclosed bays and estuaries of southernCalifornia during fall months and were reflected by the marine fish or macroinvertebrate communitiessampled at this time.DiscussionIt is somewhat premature to interpret much from the single sampling event completed thus far. It isinteresting to review the October 1997 fish sampling data for the first monitoring for the BatiquitosLagoon Enhancement Project (Merkel & Associates, 2002). At that time the lagoon had been open tothe ocean for approximately 11 months, did not yet support the extensive eelgrass beds it does today,and was similar in depth and tidal influence to <strong>Bolsa</strong> <strong>Chica</strong> at two stations. In reviewing these data, itwas found that comparable stations at Batiquitos Lagoon (Stations 3 and Station 4) yielded similardiversity and abundance.Comparison of Station 1 at <strong>Bolsa</strong> <strong>Chica</strong> to a similar interior station at Batiquitos Lagoon reveals 13species at <strong>Bolsa</strong> <strong>Chica</strong> and 15 at Batiquitos, with much higher densities at <strong>Bolsa</strong> <strong>Chica</strong> than Batiquitos(a mean density of 0.51 individuals/m 2 and 0.09 individuals/m 2 at <strong>Bolsa</strong> <strong>Chica</strong> and Batiquitos,respectively, standardized for gear type and station). Comparison of Station 2 at <strong>Bolsa</strong> <strong>Chica</strong> to asimilar interior station at Batiquitos reveals 12 species at <strong>Bolsa</strong> <strong>Chica</strong> and 17 at Batiquitos, withslightly lower densities at <strong>Bolsa</strong> <strong>Chica</strong> than Batiquitos (a mean density of 0.19 individuals/m 2 and 0.28individuals/m 2 at <strong>Bolsa</strong> <strong>Chica</strong> and Batiquitos, respectively, standardized for gear type and station).This review indicates that the fish diversity and density at <strong>Bolsa</strong> <strong>Chica</strong> were similar at this early stageof site development to another restoration project.Merkel & Associates, Inc. 33

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