Counts of organisms recorded during emergent and rapid emergent surveys conducted in the subtidal zone of northern California, Sonoma and Mendocino counties, from 1999 to 2023

The Kelp Forest Monitoring data record span surveys across 24 years from 1999 through 2023 at 20 locations on the Sonoma-Mendocino Coast, Northern California. Years without data, inclusive: 2002, 2020, 2021. These surveys are ongoing and are conducted by the California Department of Fish and Wildlife dive team with participation from dive program partners at UC Davis, UC Santa Cruz, Cal Poly Humboldt, Sonoma State, and other dive programs and volunteers. Not all sites were surveyed in all years. Surveys prior to 2000 were not conducted by the same teams or with the same methods except that all surveys were done using Scuba along 30 x 2 meter (m) transects randomly placed in the subtidal zone in rocky habitats dominated by bull kelp, Nereocystis luetkeana, forests. These randomly placed band transects surveys were stratified by depth (A=0-15, B=16-30, C=31-45, D=46-60 ft) as we know sea urchin and abalone populations differ by depth.

Data collected include the number of live, dying (in some years during the mass mortality events), and dead sea urchins (red-Mesocentrotus franciscanus and purple-Strongylocentrotus purpuratus), red abalone (Haliotis rufescens), pinto abalone (H. kamtschatkana), flat abalone (H. walallensis), as well as empty abalone shells (again in some years). Additional data collected (if Scuba bottom time and/or air allowed): red abalone size, numbers or presence of associated species such as sea stars and predators, algal group quantification, and presence of bull kelp, substrate type. Data on algae and associated species differed depending on the year and the focus of the studies in response to ecosystem conditions but all years quantified sea urchins and abalones.

These data provide a baseline of biological conditions in the kelp forest before, during and after the major marine heatwave of 2014-2016 in northern California. These data were used to manage the recreational red abalone fishery by the California Department of Fish and Wildlife from 2002 to the closure of the fishery in 2018. These data are from the two counties Sonoma and Mendocino County that had 95% of the bull kelp forests in northern California.

本海带林监测数据集涵盖1999年至2023年共计24年的调查数据，调查点位位于北加利福尼亚州索诺玛-门多西诺海岸（Sonoma-Mendocino Coast）的20处区域。调查缺失的年份包括2002年、2020年与2021年。本调查仍在持续进行，由加利福尼亚州鱼类与野生动物局（California Department of Fish and Wildlife）潜水团队主导，联合加州大学戴维斯分校（UC Davis）、加州大学圣克鲁兹分校（UC Santa Cruz）、加州州立理工大学洪堡分校（Cal Poly Humboldt）、索诺马州立大学（Sonoma State）等潜水项目合作方及志愿者共同开展。并非所有点位在每一年都接受了调查。2000年之前的调查未采用统一的调查团队与方法，但所有调查均采用水肺潜水（Scuba）方式，在以巨藻（Nereocystis luetkeana）林为主的岩质潮下带区域，沿随机布设的30×2米样带开展数据采集。此类随机带状样带调查按水深分层（A层：0-15英尺，B层：16-30英尺，C层：31-45英尺，D层：46-60英尺），因海胆与鲍鱼的种群分布随水深存在显著差异。采集的数据包括活海胆、濒死海胆（部分年份的大规模死亡事件期间）与死亡海胆的数量，其中海胆涵盖红色海胆（Mesocentrotus franciscanus）与紫色海胆（Strongylocentrotus purpuratus）；同时统计红色鲍（Haliotis rufescens）、杂色鲍（H. kamtschatkana）与平鲍（H. walallensis）的种群数量，以及部分年份采集的空鲍鱼壳数据。若水肺潜水时长与气瓶气量允许，额外采集的数据还包括：红色鲍的体长、伴生物种（如海星及其他捕食者）的数量或存在情况、藻类类群定量数据、巨藻存在情况以及底质类型。藻类及伴生物种的调查内容会随年份及针对生态系统状况的研究重点有所调整，但所有年份的调查均对海胆与鲍鱼种群进行了定量统计。本数据集为北加利福尼亚州2014-2016年大型海洋热浪发生前后及期间的海带林生物状况提供了基准参考。2002年至2018年该休闲红色鲍渔业关停前，加利福尼亚州鱼类与野生动物局曾利用本数据管理休闲红色鲍渔业。本数据采集自索诺马县与门多西诺县，这两个县域拥有北加州95%的巨藻林资源。