Bight 23 Fish Biomass

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 Assessment Reports: Bight'23 Fish Biomass南加州湾2023年区域监测计划（Bight '23）是系列区域海洋监测工作的第七项，该系列始于1994年的试点项目，并分别于1998年、2003年、2008年、2013年及2018年重复开展。共有超100家涵盖监管机构、受监管主体、学术机构及非政府组织的不同单位参与了本计划。本报告呈现了底栖鱼类与大型底栖无脊椎动物子项的监测结果，该子项是沉积物质量要素的组成部分之一，后者通过多证据链方法评估近岸生态系统健康状况。本研究采用分层随机抽样设计，对五个层区的环境状况空间范围进行评估：三个大陆架层区（4-30米、31-120米、121-200米）、一个上坡层区（201-500米）及一个海湾层区。共布设并采样122个拖网站位，采集到隶属于50个科、130个物种的鱼类共53194余尾，以及隶属于88个科、140个物种的无脊椎动物共63360余只。南加州湾（Southern California Bight，简称SCB）内、中大陆架区域（水深3至120米）中约95%的区域的鱼类响应指数（Fish Response Index，简称FRI）值符合参照基准条件。受检鱼类中，由污染物引发的胁迫异常（如外部肿瘤、损伤或鳍部糜烂）占比不足0.03%。在Bight计划系列开展的三十余年间，类参照鱼类群落的占比始终维持在较高水平，自1994年海湾监测计划（Bight '94）以来，其占参照区域的比例介于91%至100%之间。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也未呈现显著趋势或变化，表明其群落生态状态稳定。由于参与度有限，外大陆架及上坡层区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；评估报告：Bight'23 Fish Biomass