Bight 23 Station Occupation

The Southern California Bight 2023 Regional Monitoring Program (Bight '23) is the seventh in a series of regional marine monitoring efforts beginning with a pilot project in 1994 and repeated in 1998, 2003, 2008, 2013, and 2018. More than 100 different organizations encompassing regulatory, regulated, academic, and non-governmental agencies collaborated in the Bight '23 Program. This report presents the results of the Demersal Fishes and Megabenthic Invertebrates sub-element, one component of the sediment quality element that utilizes multiple lines of evidence to assess coastal ecosystem health. A stratified random sampling design was used to assess areal extent of environmental condition across five strata: three continental shelf strata (4-30 m, 31-120 m, 121-200 m), an upper slope stratum (201-500 m), and an embayment stratum. A total of 122 trawl stations were sampled, capturing more than 53,194 fishes from 50 families and 130 species, and more than 63,360 invertebrates from 88 families and 140 species. Approximately 95% of SCB inner and middle continental shelf areas (3 to 120 m depth) had Fish Response Index (FRI) values indicative of reference conditions. Pollutant-related stress anomalies such as external tumors, lesions, or fin erosion comprised less than 0.03% of all fishes examined. The extent of reference-like fish communities has remained comparably high over three decades of the Bight Program, ranging from 91% to 100% of reference area since Bight '94. Megabenthic invertebrate communities also showed no major trends or changes in traditional ecological metrics such as diversity or richness, indicating a stable ecological community. Due to limited participation, the outer shelf and upper slope strata did not meet data quality objectives for completeness and were not assessed regionally. Planning Documents: Bight23SedQualityQAPlan Bight23FieldManual Bight23SedQualityIMPlan南加州湾2023年度区域监测项目（Southern California Bight 2023 Regional Monitoring Program，下称Bight '23）是自1994年启动试点项目以来的系列区域海洋监测工作中的第七项，先后于1998年、2003年、2008年、2013年及2018年开展了后续监测。 本次Bight '23项目共有超100家涵盖监管、被监管、学术及非政府机构在内的组织参与协作。 本报告展示了底栖鱼类与大型底栖无脊椎动物子模块的监测结果——该子模块是沉积物质量要素的组成部分之一，依托多证据链开展近岸生态系统健康评估。本次监测采用分层随机抽样设计，对5个层位的环境状况空间分布进行评估：3个大陆架层位（4~30米、31~120米、121~200米）、1个上坡层位（201~500米）以及1个海湾层位。 本次共布设122个拖网采样站位，采集到隶属于50科130种的鱼类共53194尾，以及隶属于88科140种的无脊椎动物共63360只。 南加州湾（SCB）近岸与中陆架区域（水深3~120米）中，约95%的区域鱼类响应指数（Fish Response Index，简称FRI）数值符合参照基准条件。受检鱼类中，因污染物胁迫引发的异常状况（如体表肿瘤、损伤或鳍部糜烂）占比不足0.03%。 在南加州湾监测项目开展的三十余年间，参照型鱼类群落的占比始终维持在较高水平，自1994年南加州湾监测项目（Bight '94）以来，其占比区间为参照区域的91%~100%。 大型底栖无脊椎动物群落在多样性、丰富度等传统生态指标上未出现显著趋势或变化，表明其生态群落处于稳定状态。 由于参与度有限，外陆架与上坡层位未达到数据完整性的质量目标，因此未开展区域评估。 规划文件：Bight23SedQualityQAPlan、Bight23FieldManual、Bight23SedQualityIMPlan