Commercial ships represent the largest transport mechanism (vector) by which marine invasive species are moved around the globe. Tiny planktonic biota (e.g., fish and invertebrate larvae, zooplankton, phytoplankton, bacteria and viruses) occur in great numbers in unmanaged ballast water tanks. Understanding the voyage and ballast water management histories of ships, as well as the volumes of managed and unmanaged ballast water discharged to ports of the United States, enables the NBIC to assess invasion opportunity and risk associated with ships.
In order to fully evaluate the status and trends in ballast water discharge to the United States, it is useful to analyze both temporal and spatial patterns. You can explore changes in volume of discharged ballast water by category of ballast water (coastwise ballast water, overseas ballast water, or the combined total) and type of ship over time. You can determine the spatial level of interest: National, Coastal Region, or State.
Note: All data available in graphs and tables extend through the last complete month and are refreshed monthly. Because ballast water management reports may be amended, corrected or changed during quality control processes, particularly within the 20 days from arrival date for the last complete month, this may result in updates that will register when the data are next refreshed. All data are subject to change and use of any of the NBIC data implies agreement with the NBIC Data Use Agreement policy. Cite our data.
Temporal Patterns of BW Discharge
There are many interesting patterns and changes to be found in this extensive data set. Three of these are observable at the national scale and are worth noting.
- The seasonal dip in coastwise ballast water discharge is due to the season shutdown of shipping within the Great Lakes during the winter.
- Coastwise ballast water discharge has remained relatively stable throughout the record.
- Overseas ballast water discharge increased significantly first in 2007 and then again beginning in 2011.
Monthly BW Discharge by Coastal Region and State.
These interactive figures present the total reported discharge volumes of overseas ballast water (bottom in red) and coastwise ballast water (top in blue) for each month since 2005. Each month is labeled as the first day of the month. To tailor your query and figure, use the data filters located just below the chart. Select 'All Coasts' or 'All States' to view the national total; alternatively, you can select any coastal region or state to view temporal changes in discharge for that region. You can zoom and pan interactively in the figure or you can use the filter to select a specific time period. To select a date range in the chart, hold down the left mouse button and drag the arrow across the graph. To pan across the graph, hold down the 'shift' key while dragging the arrow across the graph. Click the categories in the legend to turn off or on the data that is shown in the graph for that category. The figure and data can be exported using the 'Export Chart' menu in the upper right corner of the figures.
Discharge: Coasts
| Coast | Date | Coastwise | Overseas |
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Discharge: State
| State | Date | Coastwise | Overseas |
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Temporal Patterns of Discharge by Ship Type
There are many interesting patterns and changes to be found in the NBIC data set. Three of these observable at the national scale are worth noting.
- Bulkers and tankers are responsible for the vast majority of ballast discharge since 2005.
- The largest increases in ballast water discharge have been for bulkers and tankers.
- Much of the increase in bulker discharge has been of overseas ballast water, while tankers have increased in both overseas and coastwise discharges.
Monthly BW Discharge by Ship Type and Coastal Region or State.
These interactive figure presents the total reported ballast water discharge volumes by each ship type and coastal region or state for each month since 2005. Each month is labeled as the first day of the month. To tailor your query and figure, use the data filters located just below the chart. Select 'All Coasts' or 'All States' to view the national total; alternatively, you can select any coastal region or state to view temporal changes in discharge for that region. Select the ballast water of interest (i.e., overseas, coastwise, or total). Each ship type can be 'turned on' or 'turned off' by clicking on its label in the legend (below the graph). You can zoom and pan interactively in the figure or you can use the filter to select a specific time period. To select a date range in the chart, hold down the left mouse button and drag the arrow across the graph. To pan across the graph, hold down the 'shift' key while dragging the arrow across the graph. The figure and data can be exported using the 'Export Chart' menu in the upper right corner of the figure.
Discharge: Coast & Ship Type
| Coast | Date | BW Type | Bulker | Combo | Container | General Cargo | Other | Passenger | Reefer | RoRo | Tanker |
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Discharge by Ship Type: State
| State | Date | BW Type | Bulker | Combo | Container | General Cargo | Other | Passenger | Reefer | RoRo | Tanker |
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