Recent increases in the number of high-speed, large-scale, and heavy-load vessels have made marine traffic more complex. Traffic situations are more difficult to manage as a result because of the rapid increase in the traffic density and the development of ship encounter situations. Here, we introduce a marine traffic complexity model to evaluate the status of traffic situation, use the complexity to investigate the degree of crowding and risk of collision, and support mariners and traffic controllers to get the traffic situation awareness. The traffic unit complexity model is constructed using pair-wise ship traffic characteristics such as the relative distance, relative speed, and intersecting trajectory. This model is extended to an area traffic complexity model through interpolation post-processing. We show that a higher complexity corresponds to more crowding and dangerous traffic in which the traffic situation should be carefully managed. Simulated data from the Shenzhen West Sea are employed to demonstrate the model and construct a map of the spatial distribution of the marine traffic complexity. The complexity model is shown to be effective in indicating different traffic situations.
Vessel Traffic and Tracking, Shipping, and Ports
A rapid increase in maritime traffic together with challenging navigation conditions and a vulnerable ecosystem has evoked calls for improving maritime safety in the Gulf of Finland, the Baltic Sea. It is suggested that these improvements will be the result of adopting a regionally effective proactive approach to safety policy formulation and management. A proactive approach is grounded on a formal process of identifying, assessing and evaluating accident risks, and adjusting policies or management practices before accidents happen. Currently, maritime safety is globally regulated by internationally agreed prescriptive rules, which are usually revised in reaction to accidents. The proactive Formal Safety Assessment (FSA) is applied to risks common to a ship type or to a particular hazard, when deemed necessary, whereas regional FSA applications are rare. An extensive literature review was conducted in order to examine the opportunities for developing a framework for the GoF for handling regional risks at regional level. Best practices were sought from nuclear safety management and fisheries management, and from a particular case related to maritime risk management. A regional approach that sees maritime safety as a holistic system, and manages it by combining a scientific risk assessment with stakeholder input to identify risks and risk control options, and to evaluate risks is proposed. A regional risk governance framework can improve safety by focusing on actual regional risks, designing tailor-made safety measures to control them, enhancing a positive safety culture in the shipping industry, and by increasing trust among all involved.
Maritime traffic is one of many anthropogenic pressures threatening the marine environment. This study was specifically designed to investigate the relationship between vessels presence and cetacean sightings in the high sea areas of the Western Mediterranean Sea region. We recorded and compared the total number of vessels in the presence and absence of cetacean sightings using data gathered during the summer season (2009–2013) along six fixed transects repeatedly surveyed. In locations with cetacean sightings (N = 2667), nautical traffic was significantly lower, by 20%, compared to random locations where no sightings occurred (N = 1226): all cetacean species, except bottlenose dolphin, were generally observed in locations with lower vessel abundance. In different areas the species showed variable results likely influenced by a combination of biological and local environmental factors. The approach of this research helped create, for the first time, a wide vision of the different responses of animals towards a common pressure.
Collisions between traffic and wildlife can have population-level consequences and carry economic costs. Vessel-strike may threaten the viability of whale populations especially where habitat overlaps with frequent vessel traffic; as seen in the Hauraki Gulf, New Zealand, which is the entrance to the busy Ports of Auckland and holds a year-round population of endangered Bryde’s whales (Balaenoptera edeni). Here, we identify a serious threat: out of 44 Bryde’s whale-deaths, 17 of 20 (85%), with known cause of mortality, sustained injuries consistent with vessel-strike; a mortality rate that is likely to be unsustainable. This information started a social forum with stakeholders engaged in science-based discussion of mitigation measures to reduce lethal vessel-strikes in this region. To determine the viability of different mitigation actions we studied Bryde’s whale behavior with suction-cup attached tags. Tagged whales (n = 7, 62.5 h) spent 91% of their time at depths within the maximum draft of vessels transiting the Gulf, increasing the probability of vessel-strike. Whales are broadly distributed throughout the Gulf so re-routing traffic would not lessen the threat of vessel-strike. Monitoring whales visually is difficult and not applicable at night, when whales rested closer to the surface than during the day. Passive acoustic monitoring is unreliable due to the whales’ low vocal activity and because low frequency calls are susceptible to masking from vessel noise. These findings resulted in a Transit Protocol for Shipping including voluntary speed restrictions and a monitoring plan, highlighting the value of scientific and social stakeholders working together for conservation.
An assessment of hazard stemming from operational oil ship discharges in the Southern Adriatic and Northern Ionian (SANI) Seas is presented. The methodology integrates ship traffic data, the fate and transport oil spill model MEDSLIK-II, coupled with the Mediterranean Forecasting System (MFS) ocean currents, sea surface temperature analyses and ECMWF surface winds. Monthly and climatological hazard maps were calculated for February 2009 through April 2013. Monthly hazard distributions of oil show that the zones of highest sea surface hazard are located in the southwestern Adriatic Sea and eastern Ionian Sea. Distinctive “hot spots” appear in front of the Taranto Port and the sea area between Corfu Island and the Greek coastlines. Beached oil hazard maps indicate the highest values in the Taranto Port area, on the eastern Greek coastline, as well as in the Bari Port area and near Brindisi Port area.
Understanding the implications of different management strategies is necessary to identify best conservation trajectories for ecosystems exposed to anthropogenic stressors. For example, science-based risk assessments at large scales are needed to understand efficacy of different vector management approaches aimed at preventing biological invasions associated with commercial shipping. We conducted a landscape-scale analysis to examine the relative invasion risk of ballast water discharges among different shipping pathways (e.g., Transoceanic, Coastal or Domestic), ecosystems (e.g., freshwater, brackish and marine), and timescales (annual and per discharge event) under current and future management regimes. The arrival and survival potential of nonindigenous species (NIS) was estimated based on directional shipping networks and their associated propagule pressure, environmental similarity between donor-recipient ecosystems (based on salinity and temperature), and effects of current and future management strategies (i.e., ballast water exchange and treatment to meet proposed international biological discharge standards). Our findings show that current requirements for ballast water exchange effectively reduce invasion risk to freshwater ecosystems but are less protective of marine ecosystems because of greater environmental mismatch between source (oceanic) and recipient (freshwater) ecoregions. Future requirements for ballast water treatment are expected to reduce risk of zooplankton NIS introductions across ecosystem types but are expected to be less effective in reducing risk of phytoplankton NIS. This large-scale risk assessment across heterogeneous ecosystems represents a major step towards understanding the likelihood of invasion in relation to shipping networks, the relative efficacy of different invasion management regimes and seizing opportunities to reduce the ecological and economic implications of biological invasions.
- This science advisory report is intended to provide general advice on how shipping activities may potentially impact the marine and freshwater environment. The Pathways of Effects (PoE) models included in this report are general and simply illustrate linkages that may not be universally applicable. The potential impacts of shipping can be widespread or localised, and may be chronic or acute.
- The PoE components included in this report (i.e., movement underway, discharge, oil spills, anchoring, and grounding) are independent of time and space constraints, and do not address the frequency, likelihood of occurrence, nor magnitude of potential impact(s) on an ecosystem. In no way should this advice or the PoE components be interpreted as risk or threat assessments.
- A suite of stressors resulting from movement underway (i.e. water mixing, substrate disturbance, noise emissions, icebreaking, strikes, wake, and light emission) may lead to changes in habitat, community structure, and the health (fitness) and survival (mortality) of organisms.
- Operational and incidental or accidental discharges associated with shipping can result in the discharge of aquatic invasive species, debris, oils and other aquatic or atmospheric contaminants, and nutrients (e.g., via grey water, sewage). Such discharges can result in changes to habitat, community structure, the fitness, mortality, and/or function of aquatic organisms.
- Oil spills are one of the most damaging events in the aquatic environment, affecting multiple species and habitats. Spill recovery measures are often largely ineffective and long-term chronic ecosystem effects often result.
- Anchoring may create vertical obstructions in the water column and/or may result in substantial changes to the substrate composition and structure resulting from crushing and/or sediment re-suspension. Changes to the substrate as a result of anchoring may alter benthic habitats and may result in sub-lethal impacts or an increase in mortality of benthic organisms.
- Vessel grounding can affect the substrate, habitat, and benthic organisms. Groundings are more likely near shore when approaching ports but could also occur offshore (e.g., where shallow seamounts or ridges are located).
- The environmental effects of shipping are multifaceted, with potential consequences on all structures and components of the ecosystem. As such, PoE models can be strongly inter-related leading to linkages at various levels. However, given many of the linkages have limited documentation of varying quality and quantity, predicting the PoEs can be challenging. The PoE components included in this report were developed based on the current state of knowledge with many potential linkages remaining to be thoroughly quantified.
Automatic identification system (AIS) is becoming increasingly popular with marine vessels providing accessible, up-to-date information on vessel activity in the marine environment. Although AIS has been utilised in several different fields to address specific questions, no published work has outlined the potential of AIS as a tool for a wide range of industries and users of the marine environment such as spatial planning, developments, and local marine industries (e.g. fisheries). This work demonstrates a procedure for processing, analysing, and visualisation of AIS data with example outputs and their potential uses. Over 730 000 data points of AIS information for 2013 from around Shetland were processed, analysed, and mapped. Tools used included density mapping, vessel tracks, interpolations of vessel dimensions, and ship type analysis. The dataset was broken down by sector into meaningful and usable data packets which could also be analysed over time. Density mapping, derived from both point and vessel track data, proved highly informative but were unable to address all aspects of the data. Vessel tracks showed variation in vessel routes, especially around island groups. Additional uses of AIS data were addressed and included risk mapping for invasive non-native species, fisheries, and general statistics. Temporal variation of vessel activity was also discussed.
A model is developed to calculate and spatially allocate ship engine exhaust emissions in ports and extensive coastal waters using terrestrial Automatic Identification System data for ship movements and operating modes. The model is applied to the Australian region. The large geographical extent and number of included ports and vessels, and anomalies in the AIS data are challenging. Particular attention is paid to filtering of the movement data to remove anomalies and assign correct operating modes. Data gaps are filled by interpolation and extrapolation. Emissions and fuel consumption are calculated for each individual vessel at frequent intervals and categorised by ship type, ship size, operating mode and machinery type. Comparisons of calculated port emissions with conventional inventories and ship visit data are favourable. Estimations of ship emissions from regions within a 300 km radius of major capital cities suggest that a non-negligible percentage of air pollutants may come from ships.