Research Areas > Regional Monitoring > Bight ‘08 Coastal Ecology

Project: Bight ‘08 Coastal Ecology

Background and Objectives

Three previous Bight regional surveys have focused on sampling of coastal sediments and fish to detect contaminant levels and the ecological response to contaminants. In 1994, 261 sites were sampled, followed by 416 sites in 1998, and 391 sites in 2003. Habitats sampled included the continental shelf, ports, bays and marinas, and most recently, estuaries and deep ocean basins. The Bight '08 effort expanded on the findings of the earlier surveys.

This project had two primary objectives:

1. Determine the extent and magnitude of contaminant impacts in the Southern California Bight (SCB), and whether the extent and magnitude of impacts differ among habitat types
2. Identify trends in extent and magnitude of contamination within selected habitat types

Status

This project was initiated in 2007 and completed in 2012.

Methods

This project sampled 382 SCB sites between July 1 and September 30, 2008. Sites were selected using a stratified random approach so that unbiased estimates of extent and magnitude could be made. Approximately half of the sites sampled revisited previously sampled sites in order to assess long-term trends. Sites were selected from 10 different habitats in two general categories: embayments (estuaries, marinas, ports, bays) and offshore (continental shelf, slope and basins, and the continental shelf within the Channel Islands National Marine Sanctuary). Measurements included sediment contaminant chemistry, marine debris, benthic infauna, demersal fish and megabethic invertebrate assemblages, gross fish pathology, and sediment toxicity. Additional chemicals measured in 2008 included PBDEs (flame retardants), pyrethroid pesticides, and irgarol (active ingredient in new anti-fouling paints). Additional method descriptions can be found in the Bight '08 planning documents.

Findings

Sediment toxicity results showed that sediment toxicity was not widespread in the SCB; an estimated 76% of the region showed no toxicity. No offshore stations showed moderate or high toxicity. Marinas and estuaries contained the greatest incidence of sediment toxicity, with substantial toxicity in 24% of marina sediments and 22% of estuary sediments. In addition, marina and estuary sites had the greatest prevalence of high toxicity relative to the other strata. Temporal analysis indicated that the extent of sediment toxicity in the SCB has declined over the past five years, in that substantial toxicity was absent from the offshore shelf, and the extent of toxicity in embayments has declined by approximately 50%. Additional surveys are needed to confirm these trends.

Sediment chemistry results found that the distribution of many sediment contaminants in the SCB was a function of their source inputs. The greatest concentrations of total DDT, for example, were located on the continental shelf near historic outfall sites, whereas other contaminants such as copper, zinc, and total PAHs that come primarily from vessel antifouling paints and land-based runoff ended up in embayment strata such as marinas and estuaries. When applying California's new multiple line of evidence sediment assessment tool, roughly three-quarters of the SCB sediments were in acceptable condition based on exposure to sediment contamination. The remaining one-quarter was not evenly distributed, and unacceptable condition was much more prevalent in marinas, estuaries, and ports. Over the last 10 years, sediment condition generally improved in the SCB as a whole, but this trend did not hold true for some areas like estuaries. Special studies measuring contaminants of emerging concern found pyrethroid pesticides at levels great enough to induce toxicity in the laboratory in 35% of the SCB embayment area. PBDEs, a flame retardant, were also widespread in SCB sediments.

Benthic macrofauna results showed the SCB benthos to be in overall good condition. The areal extent of disturbed benthic community remained less than 4% of the SCB from 1994 to 2008. Reference or near-reference condition was found in 99.7% of the SCB, with no evidence of disturbance to the island or mainland shelf. Macrofaunal communities in embayments, on the other hand, were more frequently disturbed. Slightly more than 12% of the embayment area contained clearly disturbed benthos, most prominently in estuaries and marinas. Benthic communities in poor condition were found over more than half the area (59.0%) of southern California estuaries and more than a third of the area (37.4%) in marinas.

Demersal fish and invertebrate communities of the SCB were relatively healthy in 2008 based on biointegrity assessment tools. Approximately 96% of the SCB had fish communities that were similar to reference conditions, and approximately 84% had megabenthic invertebrate communities similar to reference conditions. Nonreference conditions were found primarily on the inner continental shelf (<30 m depth) and bay/harbor areas, suggesting nearshore influences. Fish populations showed only background levels of anomalies and diseases, such as parasites, tumors, ambicoloration, skeletal deformities, and albinism. Debris was found throughout most (90%) of the SCB, but generally in trace amounts. Natural debris was observed three times as frequently as anthropogenic debris.

A synthesis report was prepared integrating chemistry, toxicity, and benthic biology into a single assessment of sediment quality. This integration of multiple lines of evidence is based upon the State's new Sediment Quality Objectives. Overall, 99% of the SCB was considered unimpacted by sediment contaminants. However, embayments had disproportionately greater impacts than offshore areas. While virtually none of the continental shelf area was considered impacted, at least half of the area in SCB estuaries (55%) and marinas (50%) were considered impacted.

Bight '08 Coastal Ecology data was also used in a statewide assessment of sport fish tissue contamination (summarized in a fact sheet). The survey found high contaminant concentrations in a few areas, and widespread moderate contamination throughout urban coastal regions. Methylmercury and PCBs posed the most widespread potential health concerns. Methylmercury was highest in sharks and striped bass, and PCBs were most elevated in San Francisco Bay and San Diego Bay.

Partners

This project was conducted in close cooperation with all of the SCCWRP’s member organizations. In addition, over 60 different organizations including regulated, regulatory, and non-governmental agencies collaborated on this study.

Presentations

• Bight '08 Regional Monitoring Program Key Findings: Sediment Condition (Video) - January 2012 presentation to SCCWRP member agencies on background and preliminary findings from the sediment quality analysis.

• Bight '08 Regional Monitoring Program Key Findings: Sportfish Contamination (Video) - January 2012 presentation to SCCWRP member agencies on background and findings from the sport fish tissue survey.

Fact Sheet

• Bight '08 Coastal Ecology Fact Sheet