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

Bolsa Chica Lowlands Restoration Monitoring2007 Annual Report1.4. FISH COMMUNITY MONITORINGIntroductionThe Monitoring Plan calls for fisheries monitoring to be initiated in Year 2 following the opening ofthe FTB to the ocean. The first sampling event of Year 2 was conducted during this reporting period,in October 2007.MethodologyFisheries sampling was conducted during daylight hours on October 16 and November 8, 2007.Accessibility of Bolsa Chica by survey staff due to the October wildfires in the region delayed thesecond sampling day by one week. Sampling was done at three stations: Stations 1 and 2 in the FTBand one in the Muted Pocket Marsh (Figure 1-1). No sampling was done in the MTBs due to the delayin opening them to the tidal influence of the FTB.Sampling equipment used included an otter trawl, purse seine, and beach seine at Stations 1 and 2 anda beach seine only in the Muted Pocket Marsh (MPM). A variety of depth, current, substrate, andexposure conditions exist within each station, each of which encompass large areas. To characterizethe fish communities that utilize the large sampling stations, three replicates hauls were made acrosseach station, using gear as indicated in Figure 1-5.Beach seining at Station 2 in the FTB.The beach seine consists of a 15- m x 1.8-m net with a 1.8-mx 1.8-m x 1.8-m bag in the center. The seine has 1.2-centimeter (cm) mesh in the wings and 0.6-cm mesh in thebag. It was utilized to sample shoreline waters between thebottom and surface at depths of 0 to 1 m. The seine waspositioned parallel to shore between 8 and 31 m from thewater’s edge, depending on bottom contours. The seine washeld in place for 3 minutes and then walked slowly to shore.The otter trawl consists of a 4.6-m trawl with 2-cm mesh in the body and 0.3-cm mesh in the cod end.The otter trawl was deployed at offshore sampling locations using a small vessel traveling between 1.5and 2 knots along 250-m transects. The trawl was used to sample primarily demersal offshore fish atStations 1 and 2 in the FTB. The Otter trawl was not used in the MPM due to the inaccessibility of thesite by boat.The purse seine consists of a 66-m x 6-m seine with 1.2-cm mesh in the wings and 0.6-m mesh in thebag. The purse seine was deployed at offshore sampling locations using a small vessel. This gear wasused to sample adult and juvenile fish species in the water column as well as demersal fish at Stations1 and 2 in the FTB. The purse seine was not used in the MPM due to the inaccessibility of the site byboat.If more than 100 individuals of a species were caught in a replicate of any gear type, a batch samplingprocedure was utilized. First, the standard length and weight was determined for 30 randomly selectedindividuals. Second, the batch weight was determined for 100 additional randomly selectedindividuals. Finally, the batch weight was determined for all of the remaining, uncounted individualscaught in the replicate. The number of uncounted individuals was then estimated using the batchweight of the 100 randomly selected individuals. Samples were worked up in the field and liveindividuals released.Merkel & Associates, Inc. 26