Project Background

Batiquitos Lagoon is a coastal lagoon located in the City of Carlsbad in north San Diego County between La Costa Boulevard and Poinsettia Avenue. Once a thriving tidal system, the lagoon has been largely non-tidal, experiencing infrequent tidal flow for the last 90 years. Local recognition of a need to intervene in the accelerating decline of Batiquitos Lagoon, led to the establishment of an enhancement group to develop goals and objectives for restoration of the lagoon. This led to the development of an enhancement plan by the California Coastal Conservancy in 1987. The goals of the enhancement plan includes the restoration of tidal flushing while maintaining existing habitat values.

In 1987 the Port of Los Angeles, City of Carlsbad, U.S. Fish and Wildlife Service, National Marine Fisheries Service, California Department of Fish and Game, and State Lands Commission signed an agreement towards implementing the restoration of Batiquitos Lagoon. The restoration would serve as mitigation for loss of marine resources in the Outer Los Angeles harbor due to Port construction activities. After a lengthy period of environmental documentation, design, and permitting, the restoration began in March of 1994. On December 6, 1996, the restoration was completed when the mouth of the lagoon was opened to reestablish continuous tidal flushing. The California Department of Fish and Game will manage the Lagoon using maintenance funds provided by the Port of Los Angeles.

GOALS OF THE LONG-TERM MONITORING PROGRAM

The Batiquitos Lagoon Enhancement Project is unique in several respects. Most significantly, nowhere on the west coast of the North America has such an extensive habitat rehabilitation project been undertaken in an estuarine environment. Further, seldom have such opportunities existed for observing system-wide ecosystem development from a quantified baseline. In recognition of these factors, the long-term monitoring program for Batiquitos Lagoon has been developed through project concept design, the environmental review process, and in conjunction with project permitting as well as a memorandum of agreement between the City of Carlsbad, Port of Los Angeles, and state and federal resource agencies. This monitoring program is designed to span 10 year period with monitoring efforts occurring in 1997, 1998, 1999, 2001, and 2006 (years 1, 2, 3, 5, and 10 post-construction). Monitoring activities have been contracted and will be completed by Merkel & Associates, Inc.

The monitoring program has several goals ranging from verification of mitigation acreage to documenting resource changes for application in future restoration programs. The primary monitoring program goals are as follows:

Assess compliance with mitigation requirements as outlined under project environmental certifications and approvals, permits issued for the work, and mitigation agreements between the City, Port, and resource agencies;

Document changes in the ecology of the lagoon environment over time;

Provide timely identification of any problems with the physical, chemical, or biological development of the lagoon, and;

Assist in providing a technical basis for resource management of the lagoon system by documenting maintenance needs and enhancement opportunities.

Fisheries Monitoring Studies

Station Locations

Five fish sampling stations were established within Batiquitos Lagoon. Station 1 is located in the far eastern portion of the east basin of the lagoon, between the E2 and E3 California least tern nesting colonies. Station 2 is located in the central portion of the east basin along the mudflat on the northern shore of the basin. Station 3 is located on the edge of the E1 least tern colony at the south western edge of the basin. Station 4 is located in the southwest portion of the central basin of the lagoon. Station 5 is located on a small, sandy beach adjacent to the railroad trestles in the north eastern portion of the west basin of the lagoon.

Each station consists of an onshore and an offshore sampling area. Each onshore area was staked at an elevation of +3 feet mean lower low water (MLLW) with permanent marker consisting of 2-inch diameter PVC pipe. This marker represents a central point of reference for the shore-based sampling effort which occurs along a stretch of beach of approximately 200 meters (m) in length, centered on the reference marker. The coordinates of each marker were determined in meters easting and northing using Leica 400 differential global positioning system (dGPS) set to projection WGS84, NAD83. The offshore sampling locations are within the central portions of the lagoon, offshore of each shore station.

A 250m transect was established at each offshore station with coordinates of the transect endpoints recorded using dGPS so they can be recovered for each subsequent sampling interval. During the survey, the endpoints of each transect were marked with temporary buoys; sampling replicates were completed along and to each side of the marked transects.

At a majority of the stations the offshore transect was positioned in deeper water adjacent to the onshore sampling location. However, the short sampling reach, uneven bottom, and fast currents directly offshore of the Station 5 sampling beach forced a relocation of the offshore sampling site into the souther portion of west basin, parallel to the face of the W2 tern colony.

Sampling Equipment and Methods

Six types of equipment were utilized at each station including a large beach seine, small beach seine, square enclosure, otter trawl, beam trawl, and purse seine. These gear types were chosen to be consistent with elements of other comprehensive studies of southern California bays and estuaries and will allow regional comparisons with other contemorary studies (Allen 1996, Hoffman 1996, Merkel & Associates 1997). Threefold replication was completed for each gear station. Each replicate was completed on a slightly different portion of the station beach to ensure that the same area of water was not over-sampled. Data collected for fish caught in each haul included species and individual counts, individual standard lengths, and biomass. Parasites and lesions, if any, were also noted. In addition, weather conditions, including air temperature, wind speed, tide height, wind direction, cloud cover, and precipitation, were recorded. One or more voucher specimens were collected for each species of fish collected during the monitoring effort.

The following summarizes the design specifications and deployment techniques for each of the six fisheries sampling equipment types:

Large Beach Seine The large beach seine consists of a 15.5m x 1.8m net with a 1.8m x 1.8 x 1.8m bag in the center. The seine has 1.2cm mesh in the wings and 0.6cm mesh in the bag. It was utilized to sample waters between 0-2m in depth at the onshore approximately 15-30m from the waters edge, depending on bottom contours. The seine was held in place by two researchers for three minutes and then walked slowly to shore.

Small Beach Seine The small seine consists of a 4.6m x 1.2m net with 0.3cm mesh. This seine WS utilized to sample waters between 0-0.5m in depth at the onshore locations. The seine was positioned perpendicular to the shore and held in place by one researcher standing at the edge of the water and a second researcher standing in the water. The seine was then walked parallel to the shoreline for a distance of 10m; the researcher in the water then pivoted and walked in toward the shore.

Square Enclosure The square enclosure consists of a 1m x 1m x 1m enclosed side containment vessel. The frame is constructed with PVC pipe and the four sides of the vessel are enclosed with canvas. The enclosure was deployed at shallow subtidal depths and treated with approximately 0.5L of a 1% rotenone:acetone solution. The contents of the enclosure were then searched carefully for fish and invertebrates for a 10-minute period using a long-handled dip net.

OtterTrawl The semi-balloon otter trawl has a 3.2m opening with 0.8cm mesh in the body and 0.6cm mesh in the cod end. The otter trawl was deployed at offshore sampling locations using a 14-foot skiff traveling between 1.5 and 2 knots along the established 250m transect. The otter trawl was used to sample adult and juvenile fish near mid-depth and the bottom at each station.

Beam Trawl The beam trawl consists of a 1.6m trawl with 0.4cm mesh in the wings and 0.2cm mesh in the cod end. The beam trawl was deployed at offshore sampling locations using 14-foot skiff traveling between 1.5 and 2 knots along the established 250m transect. The beam trawl was used to sample demersal fish species at each station.

Purse Seine The purse seine consists of a 66m x 6m seine with 1.2cm mesh in the wings and 0.6m mesh in the bag. The purse seine was deployed at offshore sampling locations using a 14-foot skiff. The purse seine was used to sample adult and juvenile fish species in the water column at each station.

Batiquitos Lagoon

Habitat Division

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