Southern California Bight
1998 Regional Monitoring Program:
V. Demersal Fishes and Megabenthic Invertebrates

TRAWL REPORT GROUP MEMBERS

Dr. M. James Allen -- Southern California Coastal Water Research Project
Dr. Jeff Armstrong - Orange County Sanitation District
Jeff Brown -- Southern California Coastal Water Research Project
Don Cadien - County Sanitation Districts of Los Angeles County
Elizabeth A. Caporelli - University of Southern California, Wrigley Institute of Environmental Studies
Bradley Davidson -- United States Department of Navy, Space and War Systems Center
Dr. Gregory Deets -- City of Los Angeles, Environmental Monitoring Division
Dario Diehl - Southern California Coastal Water Research Project
Dr. Douglas Diener -- MEC Analytical Systems, Inc.
Sarah Fangman - Channel Islands National Marine Sanctuary
Robin Gartman -- City of San Diego, Metropolitan Wastewater Department
Ami K. Groce -- City of San Diego, Metropolitan Wastewater Department
Jeff Grovhoug -- United States Department of Navy, Space and War Systems Center
Erica T. Jarvis - Southern California Coastal Water Research Project
Tim Mikel - Aquatic Bioassay and Consulting Laboratories
Shelly L. Moore -- Southern California Coastal Water Research Project
Dr. James A. Noblet - Southern California Coastal Water research Project
Valerie Raco-Rands - Southern California Coastal Water Research Project
Yvette Ralph - Orange County Sanitation District
Linda C. Rao - California State Water Resources Control Board
Dr. Scott A. Steinert - Computer Sciences Corporation
Christina Thomas - Orange County Sanitation District
Ronald Velarde -- City of San Diego, Metropolitan Wastewater Department
Dr. Stephen B. Weisberg -- Southern California Coastal Water Research Project

The Southern California Bight (SCB) is an important and unique ecological resource. The diverse habitats present in the SCB allow for the coexistence of a broad spectrum of species, including more than 500 species of fish and 1,500 species of invertebrates. The SCB is also one of the most densely populated coastal regions of the country, which creates stress upon the marine environment through activities such as contaminant discharge from effluents and nonpoint sources, fishing, and habitat modification. Over $10 million is spent annually to monitor coastal environmental quality in the SCB. These monitoring programs provide important site-specific information about the impacts of individual waste discharges, but do not describe the condition of the SCB as a whole. Regional information is needed by resource managers to assess cumulative impacts of contaminant inputs and to evaluate relative risk among different types of stresses.

The Southern California Bight 1998 Regional Monitoring Project (Bight'98) is part of an effort to provide an integrated assessment of the SCB through cooperative regional-scale monitoring. Bight'98 is an expansion of the Southern California Bight 1994 Pilot Project (SCBPP) (SCBPP 1998) and represents the joint efforts of 62 organizations. Bight'98 is organized into three technical components: (1) Coastal Ecology; (2) Shoreline Microbiology; and (3) Water Quality. This report represents the results of the demersal fishes and megabenthic invertebrates portion of Bight'98, which is part of the Coastal Ecology component. Copies of this and other Bight'98 reports are available for download at www.sccwrp.org.

The proper citation for this report is

Allen, M. J., A. K. Groce, D. Diener, J. Brown, S. A. Steinert, G. Deets, J. A. Noblet, S. L. Moore, D. Diehl, E. T. Jarvis, V. Raco-Rands, C. Thomas, Y. Ralph, R. Gartman, D. Cadien, S. B. Weisberg, and T. Mikel. 2002. Southern California Bight 1998 Regional Monitoring Program: V. Demersal Fishes and Megabenthic Invertebrates. Southern California Coastal Water Research Project. Westminster, CA. 572 p.

The Southern California Bight 1998 Regional Survey (Bight'98) Trawl Report Group worked cooperatively to write this report. Dr. M. James Allen of the Southern California Coastal Water Research Project (Southern California Coastal Water Research Project; SCCWRP) was responsible for writing the report as a whole, with special emphasis on recurrent group analysis, functional organization of communities, biointegrity indices, and predator-risk assessment. Erica T. Jarvis (SCCWRP) and Valerie Raco-Rands (SCCWRP) were responsible for data analysis and production of figures, tables, and appendices of the report and for bringing the report to its final completed form. The coauthors made essential contributions to specific sections of the report or to the report as a whole: Ami K. Groce (City of San Diego, Metropolitan Wastewater Department; CSDMWWD), bioaccumulation; Dr. Douglas Diener (MEC Analytical Systems), assemblages (cluster analysis); Jeff Brown (SCCWRP), biomarkers (bile FACs); Dr. Scott A. Steinert (Computer Science Corporation; CSC), biomarkers (DNA damage); Dr. Greg Deets (City of Los Angeles, Environmental Monitoring Division; CLAEMD), assemblages (cladistic analysis); Dr. James A. Noblet (SCCWRP), bioaccumulation (tissue/sediment relationships); Shelly L. Moore (SCCWRP), debris; Dario Diehl (SCCWRP), quality assurance; Erica T. Jarvis (SCCWRP) and Valerie Raco-Rands (SCCWRP), data analysis, editing, and production of new and final versions of figures, tables, and appendices across all chapters to bring the report to its final form; Christina Thomas (Orange County Sanitation District; OCSD) and Yvette Ralph (OCSD), fish and invertebrate populations chapters; Robin Gartman (CSDMWWD), fish populations (size distribution and anomalies); Don Cadien (County Sanitation Districts of Los Angeles County; CSDLAC), invertebrate populations; Dr. Stephen B. Weisberg (SCCWRP), Chair of Bight'98 Steering Committee, recommendations; Tim Mikel (Aquatic Bioassay and Consulting Laboratories; ABC), fish and invertebrate populations.

The authors thank Dr. Stephen C. Schroeter (University of California, Santa Barbara, Marine Science Center) for analysis of sea cucumber data; Dr. Robert W. Smith, for fish index analyses; Kerry Ritter (SCCWRP) for statistical advice; Linda Fuller, for technical editing; and Debbie Elmore (SCCWRP), for long hours bringing this report to its final form. We also thank all of the Southern California Bight Pilot Project (SCBPP) Trawl Group members for their participation at meetings and input to the report.

The authors also thank the Bight'98 Steering Committee for reviewing the draft reports. We are indebted to the Bight'98 Analytical Chemistry and Trawl Quality Assurance Working Groups for ensuring high-quality data for this study. We thank workers at the following organizations for their assistance in field collection and data processing: CLAEMD; CSDLAC; OCSD; CSDMWWD; MEC; ABC; CSC; Channel Islands National Marine Sanctuary; United States Navy, Space and War Systems Center; University of Southern California, Wrigley Institute for Environmental Studies; and SCCWRP.

Demersal fishes and megabenthic invertebrates inhabit the soft-bottom habitat and hence are widely distributed on the mainland shelf of the Southern California Bight (SCB). Populations of these sedentary fishes and invertebrates have been monitored extensively during the past three decades to assess impacts of treated wastewater discharge to the shelf. During this period, inputs of many anthropogenic contaminants (e.g., chlorinated hydrocarbons) to the SCB decreased significantly, and levels of these contaminants are presently low. Nevertheless, historical deposits of contaminants in the sediments may still affect populations of demersal organisms or organisms that feed on them. While demersal populations have been well studied in discharge areas, less is known about their condition throughout southern California. Earlier reference or regional studies were limited in scope or based on compilations of data from studies conducted independently in local areas.

The first synoptic regional survey of the demersal fauna of the mainland shelf of southern California was conducted in 1994. This study provided baseline information on the relative abundance of fish and invertebrate populations, distribution of their assemblages, and the extent of contamination in fish tissue. Although the study provided useful baseline information for the fauna of the mainland shelf, bays and islands were not sampled. In addition, while DDT and PCBs were widely distributed in flatfishes, the extent of area of fish with contaminant levels of concern was not determined due to lack of an appropriate threshold of concern and to the use of species with limited ranges in the SCB. In part to remedy these problems, a regional survey was conducted again in 1998. The objective of this study was to assess the status of fish and invertebrate populations and assemblages of the mainland shelf, islands, and bays, and to determine the extent of fish with contaminant levels of concern in the SCB.

Trawl samples were collected from 314 stations at depths of 2-202 m on the mainland shelf, islands, and bays from Point Conception, California to the United States-Mexico international border, from July to September 1998. The stations were selected from a stratified random sampling design. Fish and invertebrate populations were sampled by small (7.6-m headrope) semiballoon otter trawls towed for 10 min along isobaths. Fish and invertebrates were identified to species, counted, weighed by species to the nearest 0.1 kg, and examined for anomalies. Fish and sea cucumber lengths were measured to centimeter size classes. Sample collection and processing, and taxonomic identification of organisms, followed protocol delineated in a field manual designed for the study. Quality control checks were conducted before, during, and after the survey.

Data were analyzed for the SCB as a whole and for specific subpopulations. Regional subpopulations included three mainland regions (northern region -- Point Conception to Point Dume; central region -- Point Dume to Dana Point; southern region -- Dana Point to the United States-Mexico international border) and three island regions (Northwest Channel Islands - San Miguel and Santa Rosa Islands; Southeast Channel Islands - Santa Cruz, Anacapa, and Santa Barbara Islands; and Santa Catalina Island). Shelf (depth) zone subpopulations included bays and harbors (2-30 m), inner shelf (5-30 m), middle shelf (31-120 m), and outer shelf (121-202 m). Anthropogenic influence areas in shelf zone areas included the following: 1) bays/harbors -- ports, marinas, and other bays; 2) inner shelf -- river mouths, small POTW areas, "other mainland" inner shelf, and island inner shelf; 3) middle shelf -- large publicly owned treatment work (LPOTW) monitoring areas, small POTW areas, mainland non-POTW areas, and island middle shelf; and 4) outer shelf -- mainland outer shelf, island outer shelf. Fish and invertebrate population data were summarized by subpopulation and for the SCB as a whole. Fish and invertebrate assemblages were analyzed separately and as combined fish and invertebrates. Species assemblages were described by recurrent group analysis, cluster analysis, and cladistics analysis (fish and combined only). Site assemblages were described by cladistics analysis (combined only) and cluster analysis with square-root transformation of abundance data, Bray-Curtis dissimilarity index, and an agglomerative, hierarchical, flexible sorting method. The results of the cluster analysis were displayed in dendrograms and two-way tables; the results of cladistics analyses were presented as cladograms.

The fish contamination study focused on a guild (a group of ecologically similar species) rather than on individual species to attain broader areal coverage, and on predator-risk guidelines to define thresholds of concern. The guild used was the sanddab guild, a group of medium-mouthed flatfishes with generalized feeding habits, and which occurred in 96% of the samples in 1994. Whole-fish composites of Pacific sanddab (Citharichthys sordidus), longfin sanddab (Citharichthys xanthostigma), speckled sanddab (Citharichthys stigmaeus), slender sole (Lyopsetta exilis), and small (<20 cm) California halibut (Paralichthys californicus) were collected for chemical analysis. Chemical concentrations in fish tissue were compared against predator-risk guidelines for DDT, PCBs, and chlordane. Whole-fish composites of sanddab guild species were analyzed at 225 stations. Samples were composited by species in the field and frozen. Prior to chemical analysis, these samples were thawed and homogenized. Whole-fish homogenates were analyzed for 6 DDT and 2 chlordane isomers, and for PCB congeners (with focus on 12 potentially toxic congeners) using gas chromatography with either electron capture detection (GC-ECD) or mass selective detection (GC-MS). Data were summarized by subpopulation by each contaminant for the sanddab guild as a whole and for individual species. Percent of area and percent of guild above the predator risk thresholds for each contaminant were determined for the sanddab guild as a whole for the SCB and for subpopulations. Contaminant concentrations and sites above thresholds were mapped.

A fish biomarker study focused on fluorescent aromatic compounds (FACs) in the bile, (a measure of polynuclear aromatic hydrocarbon [PAH] exposure), and on DNA damage in fish blood (a measure of stress). Flatfishes were collected in bays/harbors and at the Channel Islands. The bile FACs study targeted California halibut in bays/harbors and Pacific sanddab at the islands. The DNA damage study targeted a variety of flatfish species at both locations. Concentrations of bile FACs were determined using reverse-phase, high-performance liquid chromatography and fluorescence detection. DNA damage, expressed as relative degree of strand breakage, was examined in DNA from fish blood cell nuclei. .

Of 442 attempted trawl stations, 314 (71%) were successfully sampled. Most of the 128 unsampled stations were abandoned due to the unsuitability of the seafloor for trawling. All fish and 99% of the invertebrates collected were counted. All fish and invertebrates were identified to the lowest possible taxon, with 99% of the fish and 79% of the invertebrates being identified to species. Approximately 99% of the fish counted were measured. Biomass was determined for all of the fish and 99% of the invertebrates. Measurement error was higher for biomass than for counts of individuals because biomass measurements were made on a moving boat. Anomalies audited in the field were correctly identified.

A total of 143 species of fish, representing 57 families and 4 classes, were collected in this survey. Sebastidae (rockfishes) were the most diverse family, with 24 species. Seventeen fish species occurred in 20% or more of the survey area. Two species (Pacific sanddab; California lizardfish, Synodus lucioceps) occurred in more than 50% of the survey area. Thirty-two species cumulatively comprised 95% of the fish abundance with four species (white croaker, Genyonemus lineatus; Pacific sanddab; California lizardfish; and queenfish, Seriphus politus) in combination accounting for 50% of the total abundance. Forty-four species cumulatively comprised 95% of the biomass, with five species (white croaker, Pacific sanddab, California halibut, longfin sanddab, and queenfish) in combination comprising 50% of the total biomass. Pacific sanddab was widespread (65% of the area), abundant, and high in biomass; in contrast, white croaker, queenfish, and California halibut were abundant and high in biomass but occurred in 17, 10, and 21% of the area, respectively (mostly in Los Angeles/Long Beach Harbor). Fish captured in this survey ranged in size from 3.5 cm to approximately 106.5 cm in length. Most of the fish were small, with most ranging from 4.5 to 18.5 cm in length. The modal size class (7.5 cm) of the fish comprised 12% of the catch.

Fish population attributes (abundance, biomass, species richness, and diversity) varied by region and depth. By subpopulation, median fish abundance was highest on the island outer shelf, biomass in "other bay," and species richness and diversity at the southeast Channel Islands. Lowest medians were found on the island inner shelf for all attributes. By shelf zone, the lowest values of fish abundance, biomass, and species richness were found on the inner shelf, while fish diversity was lowest in bays/harbors. However, the highest values of biomass were found in bays and harbors, and the highest values of attributes other than biomass were found on the middle and outer shelf zones. The percent of area of POTW areas with fish biomass higher than the non-POTW median was significantly higher in 1994 than in 1998.

The prevalence of fish anomalies and parasites was lower in 1998 (0.5%) than in 1994 (1.0%), and this prevalence was similar to background anomalies in the mid-Atlantic and Gulf coasts. In contrast, anomaly prevalence in 1969-1976 in the SCB was 5%. Fin erosion, an indicator of contaminated sediments, was not observed. Epidermal tumors occurred in 0.7% of Dover sole (Microstomus pacificus), the only fish with tumors. The prevalence of parasites in fish was 0.5%, with 77% of those parasitized being Pacific sanddab. Eye copepod (Phrixocephalus cincinnatus) was the primary parasite in this species.

A total of 313 species of megabenthic invertebrates representing 132 families, 21 classes, and 9 phyla were collected in the survey. Mollusks were the most diverse phylum, malacostracan crustaceans the most diverse class, and spider crabs (Majidae) the most diverse family. Fourteen species occurred at more than 20% of the stations on the mainland, with three (white sea urchin, Lytechinus pictus; California sand star, Astropecten verrilli; ridgeback rock shrimp, Sicyonia ingentis) occurring in 50% or more of the area. Twenty-four species cumulatively accounted for 95% of the total abundance, with white sea urchin accounting for 53% of the abundance. Thirty-six species cumulatively accounted for 95% of the total biomass, with four species (California sea cucumber, Parastichopus californicus; fragile sea urchin, Allocentrotus fragilis; California lamp shell, Laqueus californianus; ridgeback rock shrimp) combined accounting for more than 50% of the biomass.

Invertebrate population attributes (abundance, biomass, species richness, and diversity) varied by region and depth. By subpopulation, median invertebrate abundance, species richness, and diversity were highest at the southeast Channel Islands and biomass at Santa Catalina Island. Median invertebrate abundance and mean biomass were lowest at inner shelf small POTW areas; median species richness was lowest on the inner shelf in small POTW and other mainland areas; and diversity was lowest on the mainland outer shelf. By depth, the inner shelf zone had the lowest invertebrate abundance, biomass, and diversity, with values increasing with depth and in bays/harbors. The percent area of high invertebrate abundance and biomass was significantly higher at POTW areas in 1998 than in 1994, whereas 1994 was higher for diversity.

Assemblages were defined for fishes, invertebrates, and combined fish/invertebrates. Although a variety of methods were used, assemblages described by each were generally associated with specific depth zones. Most assemblages were found in one or more of the predetermined shelf depth zones. Distinct assemblages were identified for bays and harbors for fishes, invertebrates, and combined fish/invertebrates. San Diego Bay (a natural bay) had assemblages that were distinct from those of Los Angeles/Long Beach Harbor (an artificially enclosed part of the inner shelf zone). Distinct invertebrate site assemblages were defined for the middle shelf/outer shelf zone of the island and mainland regions. Specific fish and invertebrate assemblages were generally not associated solely with POTW areas, although one invertebrate recurrent group occurred more frequently at POTW areas than elsewhere.

Fish, invertebrate, and combined fish/invertebrate biointegrity indices identified 85-97% of the southern California shelf area as having reference (healthy) assemblages. The few nonreference sites were clustered near river mouths (especially at the Santa Clara River), suggesting runoff effects.

Some effects of the 1997-1998 El Niņo were apparent in fish and invertebrate populations and assemblages. Invertebrate populations showed an overall decrease in mean abundance, biomass, species richness, and diversity in 1998 relative to 1994 (a warm year) and 1957-1975 (a generally cooler period). The number of fish species found in 50% or more of the area decreased from six in 1994 to two in 1998. The areal occurrence of many fish foraging guilds decreased between 1994 and 1998; and many important community members expanded or shifted their distributions to deeper parts of the shelf. Two species of fish and three species of invertebrates collected in the 1998 survey had never been recorded off California prior to 1998; all normally occur from southern Baja California south.

Despite assemblage health, sanddab-guild fish with tDDT concentrations higher than the predator-risk guideline comprised 71% of the southern California shelf. Fish with PCB toxicity equivalent quotient (TEQ) concentrations higher than the mammal and bird predator-risk guidelines comprised 8 and 5% of the area, respectively. Although highest tDDT levels were found in fish from the Palos Verdes Shelf, 100% of the fish from the southeast Channel Islands were also above the predator-risk guideline, even though concentrations there were low relative to those near Los Angeles. The source of DDT is assumed to be historically deposited sediments. Although the degree of existing predator risk for DDT is not known, it is probably less than the risk of two or three decades earlier. Previous studies have shown that DDT concentrations in liver and muscle tissues of southern California fishes have decreased more than an order of magnitude during the past three decades. Port, large POTW, and "other bay" areas had the highest percent of area above the PCB TEQ guideline for mammals; whereas for birds, the percent of area above the guideline was highest for the POTW and southeast Channel Islands areas. These differences were due to variances in the relative toxicity of different PCB congeners to birds and mammals and the relative concentrations of these congeners. This first assessment of the extent of fish with contamination above predator-risk guidelines in southern California indicates that there is a large area of potential concern for tDDT and that additional study is needed to better understand the nature and degree of actual risk in local bird and mammal populations.

Biomarker analysis revealed sublethal effects in flatfishes in southern California bays and harbors. Bile FAC concentrations (an indicator of exposure to PAHs) were elevated in fish from all bays and harbors compared to Camp Pendleton, with statistically significant elevated levels found at Marina del Rey, Long Beach Harbor, and Alamitos Bay. Levels in Pacific sanddab at the Channel Islands corresponded to reference values found at Camp Pendleton in California halibut along the coast. DNA damage in California halibut blood was highest in Long Beach Harbor and lowest in King Harbor. Of seven species of flatfishes examined, speckled sanddab had the highest levels of DNA damage, and hornyhead turbot (Pleuronichthys verticalis) the lowest. Although overall, no significant relationship was found between bile FAC concentrations and DNA damage, the incidence of DNA damage increased with bile FAC concentrations in Ventura Harbor and Marina del Rey.

Anthropogenic debris (mostly plastic, metal, and cans) was found in 25% of the southern California shelf; it was most common in ports, marinas, and at Santa Catalina Island. The percent of area of natural debris was higher than anthropogenic debris in all subpopulations, but at Santa Catalina Island, both were nearly equal.

Overall, demersal fishes and invertebrate populations and assemblages in 1998 appeared to be relatively healthy, with anomalies at background levels. Biointegrity indices indicated that almost all of the area was reference, with nonreference areas being associated with river mouth areas. A few minor population attribute differences occurred at large POTW areas between 1994 and 1998. Fish and invertebrate assemblages were generally associated with shelf depth zones. Bay and harbor assemblages were distinct from coastal inner shelf assemblages, but assemblages in San Diego Bay differed from those in Los Angeles/Long Beach Harbor. Assemblages at islands were less distinct from mainland assemblages. Effects of the 1997-1998 El Niņo included reduced average population attribute values in 1998 relative to earlier years, shifts in dominant species, changes in depth ranges among species, and the addition of new species to the area.

Although populations and assemblages appear to be relatively healthy, this first study of DDT levels in sanddab guild species relative to a predator-risk guideline found that 71% of the area was above the guideline. The source of DDT exposure is assumed to be historically deposited sediments. The degree of risk to predators is not known, but is thought to be much less than two to three decades earlier. Low levels of predator risk were found for PCBs. Biomarker analysis in flatfishes showed sublethal responses and DNA damage in some bay and inner shelf species. These studies indicate that contaminant effects in demersal fishes can still be identified, even though contaminant inputs have generally decreased dramatically during the past three decades.

To download the entire report in PDF format, click on the following sections:

FRONT SECTION

Cover
Title page
Trawl Report Group Members
Foreword
Acknowledgments
Executive Summary
Table of Contents
List of Figures
List of Tables

Introduction
Materials and Methods
Quality Assurance
Demersal Fish Populations
Megabenthic Invertebrate Populations
Assemblages and Biointegrity
Bioaccumulation
Biomarkers and Sublethal Effects
Debris
Conclusions
Recommendations
Literature Cited

APPENDICES

GLOSSARY