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In addressIng climate change, the shippIng Industry, which is regarded as one sector that cannot be ignored In controllIng greenhouse gas emissions, has become a key area of concern for the International community to achieve emissions reduction targets. The International Maritime Organization-the body that regulates International shippIng-as well as the European Union and other International entities have adopted a series of emissions reduction policies, begInnIng a new era of shippIng emissions reduction. In view of the urgency and complexity of this issue, the future policy direction of shippIng emissions reduction and whether or not existIng policies can achieve the emissions reduction targets have become the focus of attention In the global shippIng Industry. In addition, ChIna's dual identity as a shippIng magnate and a developIng country plays a crucial role In the development of shippIng emissions reduction trends, and reducIng shippIng emissions is necessary for ChIna to achieve the "double carbon" commitment. In view of the above, this study endeavours to compare the current major shippIng emission reduction policies from the perspective of International law and the perspective of macro policies, and analyze the future direction of International shippIng emissions reduction policy. At the same time, the study identify ChIna as one of the key countries to Influence future policy makIng and proposes the position and path for ChIna's participation In International shippIng emissions reduction, which provided valuable contributions for ChIna to participate In acceleratIng energy transformation, explorIng participation In the carbon emission market, and promotIng International unified shippIng policy.

Since the industrial revolution the ocean has become noisier. The global increase in shipping is one of the main contributors to this. in some regions, shipping contributed to an increase in ambient noise of several decibels, especially at low frequencies (10 to 100 Hz). Such an increase can have a substantial negative impact on fish, invertebrates, marine mammals and birds interfering with key life functions (e.g. foraging, mating, resting, etc.). Consequently, engineers are investigating ways to reduce the noise emitted by vessels when designing new ships. At the same time, since the industrial revolution (starting around 1760) greenhouse gas emissions have increased the atmospheric carbon dioxide fraction x(CO2) by more than 100 μmol mol-1. The ocean uptake of approximately one third of the emitted CO2 decreased the average global surface ocean pH from 8.21 to 8.10. This decrease is modifying sound propagation, especially sound absorption at the frequencies affected by shipping noise lower than 10 kHz, making the future ocean potentially noisier. There are also other climate change effects that may influence sound propagation. Sea surface warming might alter the depth of the deep sound speed channel, ice melting could locally decrease salinity and more frequent storms and higher wind speed alter the depth of the thermocline. in particular, modification of the sound speed profile can lead to the appearance of new ducts making specific depths noisier. in addition, ice melting and the increase in seawater temperature will open new shipping routes at the poles increasing anthropogenic noise in these regions. This review aims to discuss parameters that might change in the coming decades, focusing on the contribution of shipping, climate change and economic and technical developments to the future underwater soundscape in the ocean. Examples are given, contrasting the open ocean and the shallow seas. Apart from the changes in sound propagation, this review will also d

As part of the progressive process of extending spatial plans to cover an increasing number of marine areas, with the aim of objectively balancing the interests of various users of the marine area, it has become necessary to establish the value of marine areas as a yardstick or determinant of the user group for which a given marine area is of greater value. This study seeks to fill a research gap by attempting to develop a method to calculate the value of marine areas for the commercial shipping industry. This is done to make it possible in the future to prepare the ground for policy regulating the spatial rent of the sea, whose most important users are shipowners and their ships. We use the homogeneous basin of the Polish Marine Areas (PMA) in the Baltic Sea. Based on a literature review, we conclude that such a method does not exist, posing a significant challenge in the process of marine/maritime spatial planning (MSP) and maritime policy formulation. Conducting an in-depth analysis of 2020 data on ship traffic in the basin noted above, combined with a financial analysis of shipowners' operating costs and profitability indicators, we can determine the value of marine areas both in aggregate for all shipping in the studied basin and for each of the five segments of shipping - the bulk cargo, ro-ro cargo, container, tanker, and passenger segments. in addition, through a dynamic analysis of ship traffic, it is possible to determine the value of sea area in Polish seawaters per unit of area (1 km²) at the average level and for the five specified market segments. The obtained values show that the total profits of shipowners in the Polish Marine Areas, which are at the level of more than EUR 103 million per year, and the average value of profits per 1 km² of marine area used by a ship provide future decision-makers with an objective point of reference to shape future policies for the fiscalization of public space, including the sea.

Scandinavia is the first region in the world to rely increasingly on battery-powered and thus environmentally-friendly technologies in the shipbuilding industry. After "Ampere", the world's first electrical ferry in Norway, Siemens has received a follow-up order of the Finnish shipping company FinFerries. Ampere was put into operation in Norway in May 2015, and has traveled a distance equivalent to more than 1.5 times around the equator. With the change from diesel propulsion to battery, Norwegian ship owner Norled has reduced the cost of fuel by 60 percent. For FinFerries, SIEMENS has now tailor-made a suitable technical solution for Finland's first emission-free ferry. This follow-up order confirms SIEMENS' pioneer position delivering green solutions in the shipbuilding industry.

Scandinavia is the first region in the world to rely increasingly on battery-powered and thus environmentally-friendly technologies in the shipbuilding industry. After "Ampere", the world's first electrical ferry in Norway, Siemens has received a follow-up order of the Finnish shipping company FinFerries. Ampere was put into operation in Norway in May 2015, and has traveled a distance equivalent to more than 1.5 times around the equator. With the change from diesel propulsion to battery, Norwegian ship owner Norled has reduced the cost of fuel by 60 percent. For FinFerries, SIEMENS has now tailor-made a suitable technical solution for Finland's first emission-free ferry. This follow-up order confirms SIEMENS' pioneer position delivering green solutions in the shipbuilding industry.

Assessments of ship-strike risk for large whales typically use a single year of ship traffic data and averaged predictions of species distributions. Consequently, they do not account for variability in ship traffic or species distributions. Variability could reduce the effectiveness of static management measures designed to mitigate ship-strike risk. We explore the consequences of interannual variability on ship-strike risk using multiple years of both ship traffic data and predicted fin, humpback, and blue whale distributions off California. Specifically, risk was estimated in four regions that are important for ship-strike risk management. We estimated risk by multiplying the predicted number of whales by the distance traveled by ships. To overcome the temporal mismatch between the available ship traffic and whale data, we classified the ship traffic data into nearshore and offshore traffic scenarios using the percentage of ship traffic traveling more than 24 nmi from the mainland coast, which was the boundary of a clean fuel rule implemented in 2009 that altered ship traffic patterns. We found that risk for fin and humpback whale populations off California increased as these species recovered from whaling. We also found that broad-scale, northward shifts in blue whale distributions throughout the North Pacific, likely in response to changes in oceanographic conditions, were associated with increased ship-strike risk off northern California. The magnitude of ship-strike risk for fin, humpback, and blue whales was influenced by the ship traffic scenarios. interannual variability in predicted whale distributions also influenced the magnitude of ship-strike risk, but generally did not change whether the nearshore or offshore traffic scenario had higher risk. The consistency in the highest risk from the traffic scenarios likely occurred because areas containing the highest predicted number of whales were generally the same across years. The consistency in risk from th

Unmanned surface vehicles (USVs) offer significant value through their capability to undertake hazardous and time-consuming missions across water surfaces. Recently, as the application of USVs has been extended to nearshore waterways, object tracking is vital to the safe navigation of USVs in offshore scenes. However, existing tracking systems for USVs are mainly based on cameras or LiDAR sensors, which suffer from drawbacks such as lack of depth perception or high deployment costs. in contrast, millimeter-wave (MMW) radar offers advantages in terms of low cost and robustness in all weather and lighting conditions. in this work, to construct a robust and low-cost tracking system for USVs in complex offshore scenes, we propose a novel MMW radar-based object tracking method (ROTracker). The proposed ROTracker combines the physical properties of MMW radar with traditional tracking systems. Specifically, we introduce the radar DOPPLER velocity and a designed motion discriminator to improve the robustness of the tracking system toward low-speed targets. Moreover, we conducted real-world experiments to validate the efficacy of the proposed ROTracker. Compared to other baseline methods, ROTracker achieves excellent multiple object tracking accuracy in terms of 91.9% in our collected dataset. The experimental results demonstrated that the proposed ROTracker has significant application potential in both accuracy and efficiency for USVs, addressing the challenges posed by complex nearshore environments.

1 - Before the 2020 COVID-19 pandemic, cruise ship tourism had been one of the fastest growing segments of global tourism, presenting a range of potential impacts. At Akaroa Harbour, Aotearoa New Zealand, the number of annual cruise ship visits more than quadrupled following earthquake damage to Ōtautahi Christchurch's Lyttelton Port in 2011. Akaroa Harbour is an area of core use for endangered and endemic HECTOR's dolphins (Cephalorhynchus hectori). Dolphins here are exposed to some of the highest levels of cetacean tourism in Aotearoa New Zealand. 2 - Relationships were examined between growth in cruise ship visits, as well as tours focused specifically on dolphins, and long-term trends in summer distribution of HECTOR's dolphins at Akaroa Harbour, from 2000 to 2020. Core use areas for HECTOR's dolphins within the harbour were quantified via kernel density estimation using data from 2,335 sightings from over 8,000 km of standardized survey effort. Data were allocated into four periods based on varying levels of tourism. 3 - Dolphin habitat preference varied over time, with the greatest change occurring between 2005-2011 and 2012-2015. When comparing these periods, the spatial overlap of core habitat was less than 24%. Dolphin distribution shifted towards the outer harbour after 2011 and has remained relatively consistent since. 4 - The observed shift in distribution coincided with the more than fourfold increase in annual cruise ship visits to Akaroa Harbour. Several pressures related to cruise ship tourism are likely to have influenced habitat preferences of dolphins. Further investigation into causal factors of the observed shift is warranted. 5 - in the wake of the COVID-19 pandemic, the future of cruise ship and wildlife tourism is in flux. Our findings suggest that the future re-development of this industry should follow a precautionary approach, with the onus on industry to provide evidence of sustainability before proceeding.

In 2024, the EU Intends to Include the global shippIng Industry In the European Union Emission TradIng Scheme (EU ETS). ShippIng companies will have to pay for the carbon emissions of ships over 5,000 GT on routes between EU and non-EU ports. This paper selects typical shippIng companies In the world. Based on the prInciple of fairness, historical method, baselIne method and mixed method are adopted to explore their carbon emission quota allocation. The ZSG-DEA efficiency model is used to evaluate the distribution results and verify the optimal efficiency. The research results show that the mixed method has a high efficiency of allocation. The method predicts that the carbon quota of typical shippIng companies In the world will reach the Pareto optimal allocation In 2024 and Maersk has the highest carbon emission quota among the eight typical shippIng companies, reachIng 32,431,800 tons, followed by MSC and EMC, reachIng 8,542,400 tons and 6,809,500 tons, respectively. Based on the results, we can obtaIn a reasonable allocation of carbon allowances In the EU carbon market accordIng to the proportion of busIness of shippIng companies Involved In EU routes. The research is still applicable to the allocation of carbon emmissions In future years. Therefore, this paper provides suggestions for the orderly allocation of carbon quota and carbon tradIng In the global shippIng market.

Emission trading is an efficient measure to combat climate change, which is one of the biggest threats to the international community and human health. The shipping industry has previously been considered an energy-saving industry but the growth rate of its emissions far exceeds that of other industries. On 10 May 2023, the EU enacted Regulation (EU) 2023/957, which officially included the shipping industry in the EU-ETS. Therefore, this may lead to investor-state disputes regarding emission trading in the marine industry due to the conflicts between the obligation to combat climate change and the obligation to protect investments of the host states. This has resulted in the breaching of international investment Agreements. in this context, this study aimed to propose practical recommendations for global marine market practitioners to avoid the potential risks of disputes by reflecting on the existing practice regarding climate change-related investor-state dispute resolutions and identifying the trends and problems of the current dispute resolution mechanism. These included inconsistency in the review standard, inconsistency in the review scope, and broad interpretation by the tribunal. Finally, this study proposed that by setting public purpose and exception clauses in the preambles of the international investment Agreements and incorporating the specific obligations of the foreign investors and the regulatory power of the hosting states in the drafting stage, the potential risks for disputes regarding the new EU directive in the global marine industry could be effectively reduced.

Women constitute a mere 1.28 % of currently active seafarers. This is despite the concerted international efforts over the years to promote female participation in the maritime industry. Previous studies have identified several causal factors for the dismal representation of women in this sector. However, the current disruptions in the maritime workplace, mainly caused by the introduction of digital technologies and automation, have created a novel environment that limits the relevance of several previous research findings. This study aims to address that gap by investigating the factors impacting women seafarers' participation in the transition period leading to a technology-rich, highly automated future in the maritime industry. This paper is part of a larger qualitative study that looks at workplace participation and learning by seafarers. The data for this study was collected through semi-structured interviews and focus-groups conducted among seafarers and other maritime stakeholders. The thematic analysis of the data identified some physical, social, and psychological barriers that impede the workplace participation of women seafarers. Additionally, our analysis shows that the progressive adoption of Maritime Autonomous Surface Ship (MASS) and Shipping 4.0 will play an important role in improving women's participation in the shipping sector. However, to facilitate this, maritime policy makers and educators need to ensure a level playing field by providing gender-neutral access and opportunities to acquire skills and competences essential in a highly digitalised future workplace. Improving gender diversity is an essential step to align the maritime industry with the United Nations' Sustainable Development Goal 5.

The main target of DSP in respect of Contship Italia Group, is to address the IT strategies of the various companies to guarantee an harmonious development respecting the peculiarity and the autonomy of the single realities. in the last years DSP, using the acquired know-how in the IT problems of shipping, port management and intermodal transportation has enlarged is portfolio of activities offering to the market professional services in terminal operations processes and systems deployment and optimisiation. in 2007 DSP became partner of NAVIS (part of Cargotec Corporation) and certified its staff as SPARCS 3.7 and SPARCS N4 senior consultants, carrying out various international projects. DSP has recently developed for Contship Italia Group an innovative and flexible system for automatic invoicing (Fatteuro) for container and general cargo terminals interfaced with other systems in order to manage all the necessary information to calculate and register the invoices. It is currently is use at CICT (Cagliari), EGT(Tangier), LSCT(La Spezia) and at the General Cargo Terminal SPETER of La Spezia. DSP is also tightly linked with the new University of Applied Science of Southern Switzerland. in his team a professor of this university is leading analysis and design activities and most part of his personnel has a degree in Computer Science and where recruited there. This also gives the chance to DSP to participate to research projects on the transport and IT area and to remain always skilled with the newest technology

Port and maritime studies dealing with containerization have observed traffic concentration and dispersion throughout the world. Globalization, intermodal transportation, and technological revolutions in the shipping industry have resulted in both network extension and rationalization. However, lack of precise data on inter-port relations prevent the application of wide network theories to global maritime container networks, which are often examined through case studies of specific firms or regions. This paper presents an analysis of the global liner shipping network in 1996 and 2006, a period of rapid change in port hierarchies and liner service configurations. While it refers to literature on port system development, shipping networks, and port selection, it is one of the only analyses of the properties of the global container shipping network. The paper analyzes the relative position of ports in the global network through indicators of centrality. The results reveal a certain level of robustness in the global shipping network. While transhipment hub flows and gateway flows might slightly shift among nodes in the network, the network properties remain rather stable in terms of the main nodes polarizing the network and the overall structure of the system. Additionally, mapping the changing centrality of ports confirms the impacts of global trade and logistics shifts on the port hierarchy and indicates that changes are predominantly geographic.

We examine the dive and movement behavior of blue, fin, and humpback whales along the US West Coast in regions with high ship traffic where ship strikes have been identified as a major concern. All three species are known to feed in coastal waters near areas of high ship traffic. We analyzed data from 33 archival tag deployments representing over 3,000 h of data that were attached with suction-cups or short darts for periods >20 h and recorded depth (≥ 1 Hz), fast-lock GPS positions and other sensors. There were clear differences among the three species but all showed a distinct diurnal difference in diving behavior. While dive depth varied among animals based on where prey was located, whales spent a high proportion of their time closer to the surface where they would be more vulnerable to ship strikes at night than in the day. This was most pronounced for blue whales where vulnerability was twice as high at night compared to the day. We also found differences in movement patterns of whales between day and night. Movements were more localized to specific areas in the day near prey resources while at night these movements often involved directional movements (though sometimes returning to the same area). We show how in several specific areas like the Santa Barbara Channel, these differences in movements and locations translate to a very different overlap with shipping lanes at night compared to the daytime locations, which is the basis for most sighting data.

Most species of whales are vulnerable to vessel collisions, and the probability of lethality increases logistically with vessel speed. An Automatic Identification System (AIS) can provide valuable vessel activity data, but terrestrial-based AIS has a limited spatial range. As the need for open ocean monitoring increases, AIS broadcasts relayed over earth-orbiting satellites, satellite AIS (SAIS), provides a method for expanding the range of AIS broadcast reception. We used SAIS data from 2013 and 2014 to calculate vessel density and speed over ground around the coast of Washington state in the northwestern United States. Nearby shipping lanes connecting the Ports of Seattle, Tacoma, Portland, and in Canada, Vancouver, have the greatest density of vessel traffic arriving and departing. Knowledge of shipping activity is important in this area due to the nearby presence of NOAA designated Cetacean Density and Distribution Working Group's Biologically Important Areas (BIA) for large whale species vulnerable to vessel collisions. We quantified density and speed for each vessel type that transits through BIA's. We found that cargo and tanker vessels traveled the farthest distance at the greatest speeds. As ship-strike risk assessments have traditionally relied on terrestrial AIS, we explored issues in the application of SAIS data. Temporal gaps in SAIS data led to a resulting systematic underestimation of vessel speed in calculated speed over ground. However, SAIS can be helpful in documenting minimum vessel speeds across large geographic areas and across national boundaries, especially beyond the reach of terrestrial AIS receivers. SAIS data can also be useful in examining vessel density at broad scales and could be used to assess basin-wide open ocean routes. Future use of additional satellite platforms with AIS receivers and technological advances will help rectify this issue and improve data coverage and quality.

Humans have been sailing across seas and oceans for thousands of years. However, the story of large ships capable of affecting coastal ecology and shelf sedimentary processes is only about 100 years old. Modern large seagoing vessels with a draft of 10-20 m can cause resuspension of seabed sediment, erosion of the channel slope and shoal, enhancement of seafloor sediment activity and thickening of the active layer, thereby having a significant impact on seabed topography and sedimentation processes. However, little is known about the effects of this anthropogenic agent on shelf sedimentation due to limited observational data. Here, two sediment cores were collected from a shipping lane used by vessels of 5,000- to 50,000-ton off the coast of China to analyze their sedimentary properties, with focus on both the grain size and elements. It was found that ship disturbance selectively modified the sedimentary record, with the fine-grained sediment becoming increasingly unstable. in addition, there was a reduction in grain size of sediment finer than 6.25 Φ, which decreased by 11% after the disturbance by ship. Biogenic elements that were closely related to the ecological environment were significantly altered, with Br/Cl, Si/Ti, and Ca/Ti ratios all becoming significantly smaller. This indicated that frequent disturbance caused by ships had reduced the productivity in the waters near the shipping lane. in terms of sensitivity to the effects of ship navigation, the sedimentation response was relatively rapid and began to emerge from the commencement of ship navigation, whereas the ecological response became evident later than the sedimentation response and only appeared after a significant growth in the maritime transportation of China. Following the comparison of the two sediment cores, we propose that the constant rate of supply (CRS- with ship disturbance)-constant initial concentration (CIC- without ship disturbance) dual dating model be used to establish a dati

Ship strikes are a widespread conservation issue for many cetacean species globally. Population level impacts depend on the occurrence and severity of collisions, which may lead to life altering injuries or fatalities. Such impacts are a major concern for large, long-lived, and reproductively slow species like the fin whale. Since 2014, a seasonal feeding aggregation of fin whales has been monitored from February to June off the Catalan coast (Spain), in the northwest Mediterranean Sea. Oceanographical factors influence the occurrence and high density of krill within submarine canyons along the continental shelf, resulting in high whale abundance within a small spatial area. The study area extends 37 km offshore across a 1,944 km2 marine strip situated between the towns of Torredembarra and Castelldefels. This fin whale feeding ground is exposed to high density marine vessel traffic, given its location between the northern Mediterranean shipping lane, which links Barcelona and Tarragona Ports to the Atlantic Ocean and wider Mediterranean Basin. Ship strikes represent the greatest conservation threat for fin whales in the Mediterranean Sea. At least four fin whales have been found dead in Barcelona Port since 1986 due to ship strikes and seven live whales have been documented with injuries in the study area since 2018. Fin whale distribution was mapped with known high-risk marine vessels' (cargo, tanker and passenger vessels) shipping lanes. Vessel density and shipping lanes characterised by speed were considered. Collision risk was estimated monthly based on the predicted fin whale occurrence and traffic density. Several shipping lanes crossed the fin whale feeding habitat every month with an average speed of 15 kn. Cargo vessels displayed the highest ship-strike risk during April, overlapping with the peak of fin whale sightings in the critical feeding area. Slower vessel speeds (8 kn) in waters <200 m depth or along the continental shelf should be implemented al

Efficient and rapid deployment of maritime search and rescue(MSAR) resources is a prerequisite for maritime emergency search and rescue, in order to improve the efficiency and accuracy of MSAR. This paper proposes an integrated approach for emergency resource allocation. The approach encompasses three main steps: identifying accident black spots, assessing high-risk areas, and optimizing the outcomes through a synergistic combination of an optimization algorithm and reinforcement learning. in the initial step, the paper introduces the iterative self-organizing data analysis technology (ISODATA) for identifying accident spots at sea. A comparative analysis is conducted with other clustering algorithms, highlighting the superiority of ISODATA in effectively conducting dense clustering. This can effectively carry out dense clustering, instead of the situation where the data spots are too dispersed or obvious anomalies that affect the clustering. Furthermore, this approach incorporates entropy weighting to reassess the significance of accident spots by considering both the distance and the frequency of accidents. This integrated approach enhances the allocation of search and rescue forces, ensuring more efficient resource utilization. To address the MSAR vessel scheduling problem at sea, the paper employs the non-dominated sorting genetic algorithm II combined with reinforcement learning (NSGAII-RL). Comparative evaluations against other optimization algorithms reveal that the proposed approach can save a minimum of 7% in search and rescue time, leading to enhanced stability and improved efficiency in large-scale MSAR operations. Overall, the integrated approach presented in this paper offers a robust solution to the ship scheduling problem in maritime search and rescue operations. Its effectiveness is demonstrated through improved resource allocation, enhanced timeliness, and higher efficiency in responding to maritime accidents.

Spatial risk assessments are an effective management tool used in multiple-use marine parks to balance the needs for conservation of natural properties and to provide for varying socio-economic demands for development. The multiple-use Great Barrier Reef Marine Park (GBRMP) has recently experienced substantial increases in current and proposed port expansions and subsequent shipping. Globally, large whale populations are recovering from commercial whaling and ship strike is a significant threat to some populations and a potential welfare issue for others. Within the GBRMP, there is spatial conflict between the main breeding ground of the east Australian humpback whale population and the main inner shipping route that services several large natural resource export ports. The east coast humpback whale population is one of the largest humpback whale populations globally, exponentially increasing (11% per annum) close to the maximum potential rate and estimated to reach pre-exploitation population numbers in the next 4-5 years. We quantify the relative risk of ship strike to calving and mating humpback whales, with areas of highest relative risk coinciding with areas offshore of two major natural resource export ports. We found females with a dependent calf had a higher risk of ship strike compared to groups without a calf when standardized for group size and their inshore movement and coastal dependence later in the breeding season increases their overlap with shipping, although their lower relative abundance decreases risk. The formalization of a two-way shipping route has provided little change to risk and projected risk estimates indicate a three- to five-fold increase in risk to humpback whales from ship strike over the next 10 years. Currently, the whale Protection Area in the GBRMP does not cover the main mating and calving areas, whereas provisions within the legislation for establishment of a Special Management Area during the peak breeding season in high-ris

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 persistentl

Chronic low-frequency noise from commercial shipping is a worldwide threat to marine animals that rely on sound for essential life functions. Although the U.S. National Oceanic and Atmospheric Administration recognizes the potential negative impacts of shipping noise in marine environments, there are currently no standard metrics to monitor and quantify shipping noise in U.S. marine waters. However, one-third octave band acoustic measurements centered at 63 and 125 Hz are used as international (European Union Marine Strategy Framework Directive) indicators for underwater ambient noise levels driven by shipping activity. We apply these metrics to passive acoustic monitoring data collected over 20 months in 2016-2017 at five dispersed sites throughout the U.S. Exclusive Economic Zone: Alaskan Arctic, Hawaii, Gulf of Mexico, Northeast Canyons and Seamounts Marine National Monument (Northwest Atlantic), and Cordell Bank National Marine Sanctuary (Northeast Pacific). To verify the relationship between shipping activity and underwater sound levels, vessel movement data from the Automatic Identification System (AIS) were paired to each passive acoustic monitoring site. Daily average sound levels were consistently near to or higher than 100 dB re 1 μPa in both the 63 and 125 Hz one-third octave bands at sites with high levels of shipping traffic (Gulf of Mexico, Northeast Canyons and Seamounts, and Cordell Bank). Where cargo vessels were less common (the Arctic and Hawaii), daily average sound levels were comparatively lower. Specifically, sound levels were ∼20 dB lower year-round in Hawaii and ∼10-20 dB lower in the Alaskan Arctic, depending on the season. Although these band-level measurements can only generally facilitate differentiation of sound sources, these results demonstrate that international acoustic indicators of commercial shipping can be applied to data collected in U.S. waters as a unified metric to approximate the influence of shipping as a driver of