Vessel Traffic Overview
Updated:October 9, 2009 15:04
Vessel Accidents/Casualties and Oil Spills in the Aleutians Subarea
Shipwrecks
Appendix B contains information gathered by the US Fish and Wildlife Service on locations of most of the known shipwrecks along the Aleutian chain since 1960.
US Flag Vessel CasualtiesA vessel casualty must be reported to the US Coast Guard if it occurs upon the navigable waters of the US, its territories or possessions; or whenever and wherever a casualty involves a US vessel. Public vessels and recreational vessels are exempt from these reporting requirements. Casualties include: groundings; loss of main propulsion; primary steering or reduction in maneuverability; occurrences that reduce seaworthiness (fire, flooding, damage to or loss of fire extinguishing, lifesaving or bilge pumping systems); loss of life; injuries requiring professional medical treatment; vessel damage exceeding $25,000; and spills of oil and hazardous material.
Typically, accidents, fatalities, injuries and other casualties are reported on Coast Guard standard form CG-2692 and entered into the Marine Information for Safety and Law Enforcement (MISLE) database. Approximately 14,700 accident and spill reports from US vessels operating in or near Alaska territorial waters were entered into the Coast Guard MISLE database, between June 22, 1990 and August 1, 2006.
For this study, we focused only on casualties affecting the seaworthiness of the vessel. Casualties were grouped by “first event”. For example, if a vessel lost steering, resulting in grounding, flooding, and damage to the environment by oil spill, the casualty was classed as a loss of maneuverability. We excluded first-event oil spills and personnel casualties that did not affect the overall safe navigation of the vessel, and thus reduced total number of applicable reports to 5,922. Table 8 summarizes 486 of those casualties (8.2% of the total Alaska reports) which occurred in the Aleutians Subarea. About 90% of the US vessel casualties in the Aleutians were commercial fishing vessels.Foreign Flag Vessel Casualties
Foreign vessel casualties are of interest because they generally involve larger ships with the potential for significant environmental or economic damage. Between September 12, 1991 and August 1, 2006, the US Coast Guard MISLE database contained 381 investigations of foreign vessel casualties in Alaska.
As with US flag vessels, we focused only on casualties affecting the seaworthiness of the vessel. Casualties were again grouped by “first event”. We excluded first-event spills and personnel casualties that did not affect the overall safe navigation of the vessel, and reduced total number of applicable Alaska reports to 209. The incidents were separated into seven casualty groups:
- Fire
- Grounding
- Flooding, sinking
- Material Failure (subsequent structural damage to hull or through-hull fittings)
- Collision
- Allision (Collision with a fixed object: dock, pier, dolphin, etc.)
- Loss of Maneuverability
Of the 209 casualties affecting seaworthiness of foreign vessels while operating in Alaskan waters, Table 9 summarizes the 48 casualties reported in the Aleutians (23% of the 209 total Alaska foreign vessel casualty reports). The spatial distribution of these casualties are presented in Figure 14 and detailed in Appendix C.
Loss of maneuverability was the first-event in 17 (35%) of the 48 foreign vessel casualties reported in the Aleutians Subarea.
The data in Table 9 certainly under-reports the actual number of foreign vessel casualties for the waters of the Aleutians Subarea. Foreign vessel casualties are not required to be reported to the Coast Guard unless the vessel is in the territorial waters of the US. Most vessels report casualties to their flag-state and classification society. However, this information is difficult to obtain for incidents outside of US territorial waters. Finally, loss of maneuverability, due to short-duration mechanical or electrical problems on vessels, is likely not reported to any outside agency. Loss of maneuverability is of interest in this study. Both the Kuroshima and Selendang Ayu groundings were caused by loss of maneuverability.
Spills and Potential SpillsOil spills into Alaska waters must be reported to the US Coast Guard and the ADEC. ADEC’s spills database goes back to 1995 and includes information about the potential spill size as well as the amount actually released. The NOAA Scientific Support Coordinator for the Alaska Region compiled a dataset of spills in the Aleutians going back to 1981. These data sources were used to produce Figure 15, which contains a map and list of marine vessel spills or potential spills that exceeded 1,000 gallons.
Forty-three spill events were identified and plotted. The actual amount of oil reported spilled from marine vessels was 972,343 gallons, of which 371,852 gallons was persistent oil (38%) and 600,491 was non-persistent oil (62%). Fifty percent of non-persistent oil spills were less than 3,000 gallons, yet these spills accounted for less than one percent of the total volume of non-persistent oil spilled. Twelve percent of the non-persistent spills were larger than 34,000 gallons, but these spills accounted for 66 percent of the volume of non-persistent oil spilled. Ninety-three percent of the persistent oil spills were less than 3,000 gallons, but these spills accounted for only one percent of the total persistent oil spilled. Only 7 percent of the persistent oil spills were greater than 34,000 gallons, but these spills accounted for 99 percent of the volume of persistent oil spilled.
The potential oil that might have been spilled from the 43 spill events was 5.7 million gallons, of which 2.3 million was persistent and 3.4 million was non-persistent.
