Science Symposium II - Bolsa Chica Restoration 2006-2009
By Dave Carlberg
A lineup of distinguished speakers updated about 80 attendees on the fiscal and biological state of the newly restored Bolsa Chica wetland on September 2 at Huntington Beach’s Central Library.
Bob Hoffman, biologist from the National Marine Fisheries Service and original member of the Bolsa Chica Restoration Steering Committee started the meeting with a challenging and somewhat troubling discussion of the possible uncertain financial future of the Bolsa Chica restoration. When the cost of the recent restoration was first budgeted, out of the $147 million that was received from the ports, bond issues, and other sources, about $15 million was set aside for management and future maintenance, including dredging of the inlet.
Dredging was expected to be needed about every 2 years or so, and the reserve seemed more than adequate. By investing the $15 million, the return was anticipated to provide most of the annual maintenance expenses. However, as we all know, investments of all sorts unexpectedly soured while costs soared, requiring expenses at Bolsa Chica to cut into the $15 million reserve more deeply than expected. For instance, the cost of dredging had doubled over original estimates. Hoffman expressed the concern that the maintenance fund is in danger of becoming exhausted in just a few years. He suggested several possible fixes, including a single, more efficient dredging contract that would cover all of Southern California’s wetlands rather than the piecemeal system that operates today. By instituting several similar cost-cutting moves, Hoffman believes maintenance costs could be reduced by 30 to 40 percent, protecting the reserve funds from further erosion.
The second speaker was Rachel Woodfield. Ms. Woodfield is a biologist for Merkel and Associates, the firm that is responsible for doing biological assessment surveys in the restored area. She reported on the third survey out of five that were scheduled for 1, 2, 3, 5, 6 and 10 years following restoration.
Bimonthly bird counts averaged about 8,600 birds per survey with highs around 40,000, representing 150 species. Of special interest was the endangered Belding’s Savannah Sparrow. Prior to the completion of restoration, 143 breeding pairs were sighted in Bolsa Chica, whereas in 2007, one year following completion of restoration, 361 pairs were counted. The following year there were 193, and in 2009, 269. In spite of the fluctuations in counts, Woodfield felt that since the restoration was completed, there has been a significant improvement in the condition of the breeding colony of Belding’s Savannah Sparrow in Bolsa Chica.
Fish diversity also has shown an increase. Using a variety of capture techniques, thousands of fish were collected from the full tidal basin, speciated, weighed, and measured. The results showed an increase to 46 species this year, compared to 42 last year and 19 the year before. Juvenile forms were seen in nearly all the species, meaning the wetland is fulfilling one of its intended functions, a fish nursery. Benthic samples revealed a rich variety of invertebrate species, including crabs, octopus, shrimp, mussels, oysters, clams and other organisms that form the bottom of the wetland’s food web.
Eel grass showed the most dramatic increase in the wetland’s vegetation. In 2007 0.9 acres of eel grass were planted in the full tidal basin. By 2008 the plants had covered 2 acres and in 2009, 32 acres. Eelgrass is important for stabilizing the basin bottom sand and as nursery grounds for many species of fish and shellfish. Planted cord grass showed an 89 percent increase over last year, but as Woodfield pointed out, cord grass is a plant that is known for sudden bursts of growth after several years following planting. Cord grass is essential for nesting of California Light Footed Clapper Rails, another endangered species.
Kelly O’Reilly, Department of Fish and Game biologist and Ecological Reserve Manager, reported on the state of the endangered California Least Tern’s nesting for the year. Three hundred and seventeen nests were observed in Bolsa Chica, from which 412 chicks hatched and as many as 363 fledglings resulted. O’Reilly mentioned that such figures are always estimates due to the difficulties in doing the counts. Loss of chicks was from a variety of causes, including being trampled by much larger Black Skimmers that share nesting grounds with the terns, and predation by crows, possums, brown rats, and the newest danger, gull billed terns.
California State University graduate students Thomas Farrugia and Mario Espinoza and research advisor Dr. Chris Lowe reported on the habits of certain sharks and rays that are numerous visitors in the Bolsa Chica full tidal basin. The students concentrated on two species, shovelnose guitarfish and gray smooth-hound sharks, representing 11.2 percent and 17.5 percent, respectively, of the 8 species of sharks and rays found in Bolsa Chica. They tracked the animals’ movements by acoustic telemetry where signals from sonic transmitters attached to their subjects were picked up by receivers placed throughout the full tidal basin. The animals were seen to roam the entire full tidal basin, some staying for up to 3 months before returning to the ocean. A few of the tagged animals revisited the basin for a second year.
The speakers proposed several reasons for the wetland’s popularity for sharks and rays. The water is warmer than the ocean most of the year, there is plenty of food available, and the basin is free of predators, boats, and other disturbances. The speakers emphasized the enormous value of the Bolsa Chica as a research laboratory and thanked Kelly O’Reilly for the opportunity to work in Bolsa Chica.
Two graduate students from California State University, Fullerton, Jeanette Hendricks and Tyler Flisik and their research advisor, Dr. Michael Horn, presented results of a study on the feeding habits of elegant terns in Bolsa Chica. By using a variety of methods, it was possible to determine what types of fish the terns and their chicks were feeding on. Pipefish appeared to be the principal source of food for the terns. It was initially proposed that, due to their composition, pipefish would not be as nutritious as the second most common prey of the birds, northern anchovies. In controlled laboratory feeding experiments, there did not seem to be a significant difference in the growth of elegant tern chicks fed a partial diet of pipefish versus a total diet of anchovies. Further work is planned, including learning more about the bird’s alimentary system.
Many thanks to Vic Leipzig for organizing the symposium and making it run so smoothly. Also thanks go to greeters Laura Holdenwhite and Patty Overley, and to Margaret Carlberg and Fran Pike who saw to it that the symposium nourished the body as well as the mind. And of course to the speakers we offer our deepest thanks for a totally fascinating and informative program.