Monterey Bay National Marine Sanctuary Research Articles

Mapping offshore anthropogenic infrastructure associated with Cannery Row, Monterey Peninsula, California USA

“Cannery Row” is well known from the novel of the same name written by John Steinbeck in 1945. It historically extends back to the early 1940’s when sardines were being heavily fished in Monterey Bay and an extensive network of canneries were established in Monterey. To support these canneries and the fishing vessels delivering fish to the shore-based processing facilities, an extensive network of seabed infrastructure was developed. Once the fisheries collapsed, the canneries shut down and the “Row” became derelict with the seabed infrastructure left to deteriorate in place. Today the row has been revitalized by an invigorating tourist industry brought to the peninsula with the establishment of the Monterey Bay Aquarium (MBA) nearly 40 years ago. New seabed infrastructure was constructed to support the aquatic exhibits of the MBA but unlike the previous canneries’ infrastructure, this infrastructure was constructed with the conservation of the unique and spectacular nearshore marine environment in mind.Using modern geophysical instrumentations consisting of Multi-Beam Echosounder (MBES) and 3.5 kHz Compressed High Intensity Radar Pulse (CHIRP) sub-bottom profiling systems we mapped the seafloor geology, imaged abandoned and present-day seabed infrastructure, and characterized the benthic habitats. From this mapping effort we were able to assess the artifacts of the seafloor and illustrate how modern seafloor processes such as sediment transport is altering the infrastructure. Much of the abandoned submarine infrastructure provides hard substrate within a dynamic unconsolidated sand bottom that is habitat for encrusting and sessile organisms, contributing to the diversity and complexity of the marine ecosystem of the area. In addition, a prominent granodiorite exposure upon which the dynamic sand onlaps is prime holdfast foundation for kelp that in turn provides habitat for fish. Although not pristine, the impacts of previous industrial disturbances and anthropogenic impacts are now well mitigated with the area set aside as a natural reserve and educational center piece within the Monterey Bay National Marine Sanctuary.

Epibenthic faunal community dynamics and seasonal species turnover in a deep-sea coral ecosystem

Deep-sea coral ecosystems represent oases of life in the deep ocean, often hosting abundant and diverse faunal communities. Although mounting evidence indicates that deep-sea benthic communities are highly dynamic and can change over scales of a few hours to seasons or years, such dynamics have never been characterized in deep-sea coral ecosystems. We used a time-lapse camera deployed for a year at a depth of 1230 m on Sur Ridge (Monterey Bay National Marine Sanctuary) to characterize hourly changes in megafaunal abundance and diversity in a deep-sea coral assemblage. The response of community dynamics to variation in environmental factors, including surface net primary production as well as current speed/direction, temperature and acoustic backscatter (a proxy for particle and zooplankton density) at depth, was also evaluated. Overall, 33 taxa from 6 phyla, including multiple commercially valuable species, were observed throughout the study period. The strong seasonal pattern and periodicities in the occurrence of the most abundant taxa likely drove the observed temporal trends in overall abundance and diversity. Fluctuations in food availability may have, at least partially, driven these trends, as indicated by the significant relationship between community dynamics, surface net primary production and acoustic backscatter at depth. However, the low explanatory power of environmental parameters tested here suggest that biotic factors such as individual behaviors and species interactions had a strong influence on community dynamics. This study emphasizes the role of deep-sea coral as habitat and the need for monitoring to better understand how environmental and biological processes interact to shape associated faunal communities.

Using passive acoustic monitoring to characterize vocal behaviors of sperm whales (Physeter macrocephalus)

Sperm whales (Physeter macrocephalus) have been observed but not well studied in the Monterey Bay National Marine Sanctuary (MBNMS). Vessels transiting through MBNMS may pose a threat to sperm whales and modify their behavior. Knowledge of their activity in relation to vessel presence in MBNMS is largely unknown. In this study, passive acoustic monitoring (PAM) data collected at the Sur Ridge, in close proximity to shipping lanes, are used to characterize vocal and foraging behaviors of sperm whales in relation to vessel transits through MBNMS. PAMGuard automated detectors are used to detect sperm whale clicks and measure inter-pulse intervals with feature-based post-processing to reduce false positives. Probability density functions are used to determine distribution of sperm whale size, sex, and presence in relation to vessel transits. Foraging clicks were positively detected in sequences of bouts from June-August, 2020. Sperm whales observed were adult males. Container ship signatures were observed to cover the same frequency bandwidth as sperm whales with a higher amplitude. This study provides insight on the importance of MBNMS to sperm whales and informs policy makers on potential effects that shipping may have on sperm whale behavior, while providing a novel method to analyze PAM data.

Building on a human-centred, iterative, and agile co-design strategy to facilitate the availability of deep ocean data

AbstractCurrent information on the status and trends of ocean change is needed to support effective and responsive management, particularly for the deep ocean. Creating consistent, collaborative and actionable mechanisms is a key component of the Deep Ocean Observing Strategy, a program of the United Nations Decade of Ocean Science for Sustainable Development. Here, we share an iterative, agile, and human-centred approach to co-designing datastreams for deep-sea indicators that serves stakeholders, including US National Marine Sanctuaries, presented as a four-phase project roadmap initially focused on the Monterey Bay National Marine Sanctuary, and then generalized to other areas such as the US West Coast, offshore wind development areas, and managed marine spaces globally. Ongoing efforts to provide key physical, biogeochemical, biological, and ecosystem variables for California's Marine Protected Areas are informing this co-design process. We share lessons learned so far and present co-design as a useful tool for (1) assessing the availability of information from deep ecosystems, (2) ensuring interoperability, and (3) providing essential information on the status and trends of indicators. Documenting and sharing this co-design strategy and scalable four-phase roadmap will further the aims of DOOS and other initiatives, including the Deep Ocean Stewardship Initiative and Challenger 150.

Expanding the temporal and spatial scales of environmental DNA research with autonomous sampling

AbstractEnvironmental DNA (eDNA) is an emerging and powerful method for use in marine research, conservation, and management, yet time‐ and resource‐intensive protocols limit the scale of implementation. Long‐range autonomous underwater vehicles equipped with autonomous environmental sample processors (LRAUV‐ESPs) provide a new means for scaling up marine eDNA sample collection and processing. Here, we used eDNA metabarcoding of four marker genes (mitochondrial 12S rRNA, bacterial and archaeal 16S rRNA, nuclear 18S rRNA, and mitochondrial COI), which encompass the diversity of marine species from microbes to vertebrates, to demonstrate the efficacy of an LRAUV‐ESP in sampling eDNA and assessing community structure in the Monterey Bay National Marine Sanctuary. The sequencing results from samples that were autonomously collected were comparable with those collected from a ship at similar locations, times, and depths, supporting previous results that found no significant differences using targeted qPCR. This study demonstrates the potential of equipping autonomous underwater vehicles with ESPs to greatly expand the scale of eDNA sample collection and processing and provide much needed information regarding the changing spatial and temporal patterns of marine biodiversity, especially in many data‐poor regions of the world's oceans.

Editorial: Before-After Control-Impact (BACI) Studies in the Ocean

BACI is not a perfect methodology, as site choice and sampling rate need to be determined strategically (Smokorowki and Randall, 2017), but baseline studies before expected large-scale impacts lend themselves to the “before” or “control” portions of BACI experiments. [...]learning how to best implement BACI methodologies from other ecological fields and applying them to the ocean could provide a common language for understanding human impacts. The articles show that sound was significantly reduced during the early months of the pandemic (1) at a cold-water coral reef under a passenger ferry route between Norway and Sweden (De Clippele and Risch), (2) in a high-traffic area for cruise ships in Glacier Bay National Park in Alaska (Gabriele et al.), (3) in a sperm whale habitat in the Bahamas (Dunn et al.), (4) at two sites in the Baltic Sea (Basan et al.), (5) in the Monterey Bay National Marine Sanctuary (Ryan et al.), and (6) in the Halifax Harbor of Nova Scotia (Breeze et al.). Fernandez-Betelu et al. found that far-field impulsive sounds from pile driving do not force coastal bottlenose dolphins to vacate their habitat, but do affect their behavior, whereas Benhemma-Le Gall et al. determined that harbor porpoises were displaced during pile-driving activities and from associated construction vessel activity for offshore wind farms. [...]Stack et al. used a “before-after” scale of hours in a tropical environment in Australia, to show potentially detrimental behavioral changes in humpback whales due to ecotourism activities.

Reduction of Low-Frequency Vessel Noise in Monterey Bay National Marine Sanctuary During the COVID-19 Pandemic

Low-frequency sound from large vessels is a major, global source of ocean noise that can interfere with acoustic communication for a variety of marine animals. Changes in vessel activity provide opportunities to quantify relationships between vessel traffic levels and soundscape conditions in biologically important habitats. Using continuous deep-sea (890 m) recordings acquired ∼20 km (closest point of approach) from offshore shipping lanes, we observed reduction of low-frequency noise within Monterey Bay National Marine Sanctuary (California, United States) associated with changes in vessel traffic during the onset of the COVID-19 pandemic. Acoustic modeling shows that the recording site receives low-frequency vessel noise primarily from the regional shipping lanes rather than via the Sound Fixing and Ranging (SOFAR) channel. Monthly geometric means and percentiles of spectrum levels in the one-third octave band centered at 63 Hz during 2020 were compared with those from the same months of 2018–2019. Spectrum levels were persistently and significantly lower during February through July 2020, although a partial rebound in ambient noise levels was indicated by July. Mean spectrum levels during 2020 were more than 1 dB re 1 μPa2 Hz–1 below those of a previous year during 4 months. The lowest spectrum levels, in June 2020, were as much as 1.9 (mean) and 2.4 (25% exceedance level) dB re 1 μPa2 Hz–1 below levels of previous years. Spectrum levels during 2020 were significantly correlated with large-vessel total gross tonnage derived from economic data, summed across all California ports (r = 0.81, p < 0.05; adjusted r2 = 0.58). They were more highly correlated with regional presence of large vessels, quantified from Automatic Identification System (AIS) vessel tracking data weighted according to vessel speed and modeled acoustic transmission loss (r = 0.92, p < 0.01; adjusted r2 = 0.81). Within the 3-year study period, February–June 2020 exhibited persistently quiet low-frequency noise and anomalously low statewide port activity and regional large-vessel presence. The results illustrate the ephemeral nature of noise pollution by documenting how it responds rapidly to changes in offshore large-vessel traffic, and how this anthropogenic imprint reaches habitat remote from major ports and shipping lanes.

Integrating Biodiversity and Environmental Observations in Support of National Marine Sanctuary and Large Marine Ecosystem Assessments

Species and habitats are the subjects of legislation that mandates reporting of information on ecosystem conditions. Improvements in sensors, sampling platforms, information systems, and collaborations among experts and information users now enables more effective and up-to-date information to meet regional and national needs. Specifically, advances in environmental DNA (eDNA)-based assessments of biodiversity, community science data, various underwater imaging devices, and environmental, behavioral, and physiology observations from animal telemetry provide new opportunities to address multiple requirements for reporting status and trends, including insights into life in the deep ocean. Passive and active acoustic sensors help monitor marine life, boat traffic, and noise pollution. Satellites provide repeated, frequent, and long-term records of many relevant variables from global to local scales and, when combined with numerical computer simulations, allow planning for future scenarios. Metadata standards facilitate the transfer of data from machine to machine, thus streamlining assessments and forecasting and providing knowledge directly to the public. The Marine Biodiversity Observation Network (MBON) facilitates this exchange of information on life in the sea. The collaborative efforts of the Central and Northern California Ocean Observing System (CeNCOOS) of the US Integrated Ocean Observing System and its partners provide an example of a regional MBON process for information delivery. This includes linking policy and management needs, prioritizing observing data from various platforms and methods, streamlining data handling practices, and delivery of information for management such as for the Monterey Bay National Marine Sanctuary and the California Current Large Marine Ecosystem, with iterative process adaptation.

Microplastics and microfibers in surface waters of Monterey Bay National Marine Sanctuary, California

Despite a recent report of high concentrations of microplastics and microfibers in the mesopelagic waters of Monterey Bay National Marine Sanctuary (MBNMS), little is known about these particles in surface waters. From 2017 to 2019, we sampled two nearshore and two offshore locations within MBNMS using a manta trawl and analyzed these samples for microplastics and microfibers. We found an average concentration of 1.32 ± 0.70 (SE) particles per m3. We found the highest concentration of particles closest to shore, and the lowest concentration above the remote Davidson Seamount. Fiber-like debris was more common in offshore, as compared to nearshore, sites. Overall, particles in our samples were primarily buoyant synthetic polymers, including polypropylene and polyethylene. Our results provide baseline data on the degree of microplastic and microfiber pollution in MBNMS surface waters and confirm that this pollution can be found in waters from the surface to at least 1000 m depth.

Quieting of low-frequency vessel noise in Monterey Bay National Marine Sanctuary during the COVID-19 pandemic

Low-frequency sound from large vessels is a major source of ocean noise, overlapping the range of marine animal communication. Changes in vessel activity provide opportunities to quantify the relationship between traffic levels and soundscape conditions in biologically important habitats. Using continuous deep-sea (890 m) recordings ∼20 km from shipping lanes, we observed quieting of low-frequency noise within Monterey Bay National Marine Sanctuary (California, USA) during the COVID-19 pandemic. Noise levels in the frequency band 31–100 Hz, which captured large vessel noise while minimizing potential biases from geological and biological sound sources, decreased during January–June 2020. At monthly resolution the 2020 quieting trend correlated with decreasing cumulative hours of vessel presence derived from Automatic Identification System (AIS) data for cargo vessels (r = 0.92; p = .01), and the sum of all positively correlated vessel types (cargo, towing, dredging, passenger, tanker; r = 0.88; p = 0.02). February–June 2020 levels were up to 2.7 dB re 1 μPa2/Hz below baseline of the two years prior. While anticipated to be short-term, at their peak these changes represent nearly a halving of acoustic power, emphasizing the significance of offshore large vessel traffic to sound levels in deeper waters in the sanctuary.

Humpback whale song analysis based on automatic classification performance

Song is a prevalent behavior in humpback whale populations, even in regions that are considered to be foraging habitat such as the Monterey Bay National Marine Sanctuary in the Northeast Pacific, where song is detected nine months out of the year. In this work, we explore various machine learning methods to classify song units, as a basis for studying song structure and its changes. We report on a number of analyses and classification exercises based on linear predictive coding, vector quantization, and machine learning classifiers including Naive Bayes, first-order Markov chain, and Hidden Markov modeling. As a baseline for comparison purposes, the distortion measure used to create the codebooks for vector quantization is itself also used as a means for classification. With classification accuracy ranging from 65% to 83% across the selected methods on a 4.5 h recording involving 5000 unit occurrences over 20 different unit types, we evaluate the effect of several signal processing, clustering, and learning parameters on classification performance with the goal of laying a foundation that can be used to characterize song vocalization at not only the unit level but also below (subunit) and above (phrase, theme, song).

Annotated checklist of fishes from Monterey Bay National Marine Sanctuary with notes on extralimital species.

Monterey Bay National Marine Sanctuary is a federal, marine protected area located off the central coast of California, USA. Understanding biodiversity, and how it is changing, is necessary to effectively manage the sanctuary. The large size of this sanctuary, which contains a variety of habitats and is influenced by several water masses, provides for a diverse fish fauna. The central California coast has a rich history of ichthyological research and surveys, contributing to a unique repository of information on fish diversity. Herein, we provide a checklist of fishes that occur within the sanctuary, including justification for each species. Ancillary record information including name-bearing type specimens, historic species, cold- or warm-water event species, introduced species, and occurrence at Davidson Seamount or Elkhorn Slough are also provided. This represents the first comprehensive annotated checklist of 507 fishes known to occur within the sanctuary. In addition, 18 species are considered to be extralimital. This annotated checklist of fishes can be used by those interested in zoogeography, marine protected areas, ichthyology, regional natural history, and sanctuary management.

Integrative passive acoustic monitoring in Monterey Bay National Marine Sanctuary

Monterey Bay National Marine Sanctuary, in the highly productive California Current System, is vital habitat for many marine mammal species. Passive acoustic monitoring (PAM) is an effective means to detect species’ presence and acoustic behavior. Using the infrastructure of a cabled observatory and detection and classification of sound sources, we examine applications of PAM as an essential part of ecosystem-based research and management. The first case study integrates PAM with multidisciplinary data—whale sighting rates, forage species’ abundances, levels of primary production, concentrations of a neurotoxic algal compound, and acoustic modeling results—to examine how occurrence patterns of humpback whale song reflect ecosystem variations. The second case study takes a similar approach to examine blue whale call occurrence, with emphasis on varying detection and classification methods for different call types. The third case study examines an anthropogenic sound source: explosives intended to deter interference of pinnipeds in fishing operations. Toward new developments that are proving insightful, we consider three further approaches: (1) application of unsupervised machine learning methods to advance characterization of humpback whale song structure; (2) integration of PAM and active acoustic sensing to examine predator-prey relationships; and (3) integration of PAM time-series analyses with data from animal tags.

Quantifying marine debris associated with coastal golf courses

Identifying terrestrial sources of debris is essential to suppress the flow of plastic to the ocean. Here, we report a novel source of debris to the marine environment. From May 2016 to June 2018, we collected golf balls from coastal environments associated with five courses in Carmel, California. Our 75 collections recovered 39,602 balls from intertidal and nearshore environments adjacent to, or downriver from, the golf courses. Combining our collections with concurrent efforts of the Monterey Bay National Marine Sanctuary and the Pebble Beach Corporation, we report the retrieval of 50,681 balls, totaling approximately 2.5 tons of debris. We also examined decomposition patterns in the collected balls, which illustrate that degradation and loss of microplastic from golf balls to the marine environment may be of concern. Our findings will help to develop and direct mitigation procedures for this region and others with coastal golf courses.

Mercury and selenium concentrations in Scyphozoan jellyfishes and pyrosomes from Monterey Bay National Marine Sanctuary

Gelatinous zooplankton including jellyfishes, pyrosomes, and salps serve as important prey items for a number of marine species; however, relatively few studies have examined contaminant concentrations in these animals. Scyphozoans (Aurelia sp., Chrysaora colorata, C. fuscescens, and Phacellophora camtschatica) and Thaliaceans (Pyrosoma sp.) were collected from 2009 to 2011 from Monterey Bay National Marine Sanctuary and analyzed for total mercury and selenium concentrations. In general, mercury (0.0001–0.0016 μg/g wet weight) and selenium (0.009–0.304 μg/g wet weight) concentrations of the sampled organisms were low; however, the two Pyrosoma sp. had total mercury and selenium concentrations that were one order of magnitude higher than the Scyphozoans. There was a significant positive relationship between mercury and selenium concentrations in jellyfishes and pyrosomes, suggesting a potential detoxification mechanism in these lower trophic level organisms. This study provides evidence that trophic transfer of mercury and selenium likely occurs through ingestion of gelatinous prey.

Temporal variations in humpback whale (Megaptera novaeangliae) song in Monterey Bay National Marine Sanctuary, northeast Pacific

Using two years of nearly continuous recordings from Monterey Bay National Marine Sanctuary, August 2015 through July 2017, variations in humpback whale song are examined on diel, seasonal, and interannual time scales. The cabled hydrophone is in humpback feeding and migratory habitat at 36.7128°N, 122.186°W. Diel analyses show 69% of song during night, 23% during day, and 8% during dusk or dawn. Seasonal analyses show song absence during summer (June–August), emergence during fall (September–October), peak during late fall/winter (November–January), and highly variable detection during spring (February–May). During both years >80% of song occurred during the November–January peak. Song detection within a month reached a maximum of 58% of the time during November 2016. Song length increased (p < 0.01) month-to-month from the start in fall through the end of the peak in January. The months of maximum song occurrence coincide with declining visual sighting of humpbacks within Monterey Bay, consistent with seasonal southward migration to breeding habitat and/or more offshore residence. Interannual variation in song was marked by a 51% increase between the first and second years. Habitat during the first year was strongly influenced by a prolonged regional oceanic warm anomaly and the largest toxic algal bloom ever recorded in the northeast Pacific. Alternative hypotheses for the interannual difference in song detection relate to differences in humpback regional abundance, behavior, and habitat occupancy.

Biomonitoring of marine vertebrates in Monterey Bay using eDNA metabarcoding.

Molecular analysis of environmental DNA (eDNA) can be used to assess vertebrate biodiversity in aquatic systems, but limited work has applied eDNA technologies to marine waters. Further, there is limited understanding of the spatial distribution of vertebrate eDNA in marine waters. Here, we use an eDNA metabarcoding approach to target and amplify a hypervariable region of the mitochondrial 12S rRNA gene to characterize vertebrate communities at 10 oceanographic stations spanning 45 km within the Monterey Bay National Marine Sanctuary (MBNMS). In this study, we collected three biological replicates of small volume water samples (1 L) at 2 depths at each of the 10 stations. We amplified fish mitochondrial DNA using a universal primer set. We obtained 5,644,299 high quality Illumina sequence reads from the environmental samples. The sequence reads were annotated to the lowest taxonomic assignment using a bioinformatics pipeline. The eDNA survey identified, to the lowest taxonomic rank, 7 families, 3 subfamilies, 10 genera, and 72 species of vertebrates at the study sites. These 92 distinct taxa come from 33 unique marine vertebrate families. We observed significantly different vertebrate community composition between sampling depths (0 m and 20/40 m deep) across all stations and significantly different communities at stations located on the continental shelf (<200 m bottom depth) versus in the deeper waters of the canyons of Monterey Bay (>200 m bottom depth). All but 1 family identified using eDNA metabarcoding is known to occur in MBNMS. The study informs the implementation of eDNA metabarcoding for vertebrate biomonitoring.

The correlation between the local environment and gray whale behavior as tracked using a sparse hydrophone array in Monterey Bay National Marine Sanctuary

Gray whales (Eschrichtius robustus) make one of the longest annual migrations of any marine mammal. While the seasonal periodicity of the migration and related travel corridors have been well-studied, little is known about how these whales use acoustics while migrating. Acoustic array processing is a powerful tool to localize and track vocalizing whales without disrupting their behavior. Concurrent with the NOAA Southwest Fisheries Science Center visual and infrared gray whale census, four hydrophone-recorder packages with sites separated by approximately 2 km in 58 to 110 m water in Monterey Bay National Marine Sanctuary offshore of Granite Canyon, California, recorded from November 2014 to June 2015. An automatic call detector identified gray whale M3 calls in the dataset. Spectrogram cross-correlation was used to measure the time-difference-of-arrival of these calls and estimate the location of the calling animal. These localizations provide gray whale swimming and calling behavior and indicate changes on diel and seasonal time scales. Results from 15 high-quality tracks show calling gray whales swimming at a mean speed of 1.97 m/s with a range of 1.18 to 2.54 m/s. Acoustic detections and tracks are compared with environmental parameters to investigate how gray whale behavior relates to their physical environment. These results are necessary for understanding the cues gray whales use to navigate from their feeding grounds offshore of Alaska to their breeding grounds in Baja California.

Assessment of the Deep Sea Wreck USS Independence

As part of ongoing efforts to better understand the nature of shipwrecks in National Marine Sanctuaries which may pose some level of pollution risk, and in this case, to definitively locate what is likely the only shipwreck in a sanctuary involved in both nuclear testing and nuclear waste disposal, NOAA’s Office of National Marine Sanctuaries collaborated with NOAA’s Office of Ocean Exploration and The Boeing Company, which provided their autonomous underwater vehicle, Echo Ranger, to conduct the first deep-water archaeological survey of the scuttled aircraft carrier USS Independence in the waters of Monterey Bay National Marine Sanctuary (MBNMS) in March 2015. The presence of the deep-sea scuttled “radioactive” aircraft carrier USS Independence off the California coast has been the source of consistent media speculation and public concern for decades. The survey confirmed that a sonar target charted at the location was Independence, and provided details on the condition of the wreck, and revealed no detectable levels of radioactivity. At the same time, new information from declassified government reports provided more detail on Independence’s use as a naval test craft for radiological decontamination as well as its use as a repository for radioactive materials at the time of its scuttling in 1951. While further surveys may reveal more, physical assessment and focused archival work has demonstrated that the level of concern and speculation of “danger” from either a radioactive or oil pollution threat posed may be exaggerated.

Initial Archaeological Survey of the ex-USS Independence (CVL-22)

The Boeing Company, collaborating with NOAA to address innovative ways to make ocean observations, provided their autonomous underwater vehicle, Echo Ranger, to conduct the first deep-water archaeological survey of the scuttled aircraft carrier USS Independence in the waters of Monterey Bay National Marine Sanctuary in March 2015. While a preliminary effort, and not comprehensive, the survey confirmed that a sonar feature (previously not proven to be an archaeological feature) charted at the location was Independence, and provided details on the condition of the wreck. At the same time, new information from declassified government reports provided more detail on Independence’s use as a naval test craft for radiological decontamination as well as its use as a repository for radioactive materials at the time of its scuttling in 1951. The wreck is historically significant, but also of archaeological significance as an artifact of the early years of the atomic age and of the Cold War. This article summarizes Independence’s contexts, its nuclear history, and the results of the survey of the wreck site.