U.S. Fish and Wildlife Service Response to Vessel Grounding/Oil Spill off Unalaska Island

December 21, 2004: Response vessels remain in Dutch Harbor for the duration of the current severe weather pattern. An overflight by helicopter of the vessel, shoreline and wildlife was scheduled to take place today during a brief weather window, but conditions did not permit it. Gale and heavy freezing spray warnings continue through tonight. Before returning to Dutch Harbor, biologists continued surveys from skiffs. They also removed carcasses from beaches wherever possible, in order to prevent secondary poisoning and oiling of wildlife that quickly feeds on any carcass. However, due to the small area that has been surveyed and the much larger area that has not, concern remains high for secondary poisoning and oiling from scavenged carcasses in other areas not yet accessed, as well as direct impacts by oiling in those areas. Capture of any live oiled species is especially difficult not only because of recent weather conditions and short daylight hours but also the tendency of oiled animals to tuck themselves away or become extremely skittish and evade capture. True numbers of oiled wildlife remain unknown but are assumed to be much larger than what has been observed. Wintering concentrations of some birds will also be arriving in the area over the next few weeks. So far, 611 oiled birds have been observed; 20 oiled dead birds and one oiled dead sea otter have been collected; and 20 live birds have been captured.

As soon as the weather permits, the wildlife missions will resume, with bird surveys/rescues by skiff, and shoreline teams collecting carcasses and documenting shoreline impacts. Prior to the storm, a soybean foam line was observed about two miles long. A few birds were seen swimming through it. Additionally, piles of soaked soybeans about 3 feet deep have been observed on some shoreline areas. Potential impacts from the spill of the vessel’s cargo of 66,000 tons of soybeans are unknown.

The oil being spilled is known as “Bunker C.” This is a dense, viscous oil produced by blending heavy residual oils with a lighter oil - often No.2 diesel fuel oil. When spilled on water, it usually spreads into thick, dark colored slicks. Bunker C will also break up into patches and tarballs, and can sink to the bottom. It is a persistent oil; only 5 to 10% evaporates within the first hours of a spill. Consequently, the oil can be carried hundreds of miles in the form of scattered tarballs, by winds and currents. The tarballs will vary in diameter from few centimeters to several meters, and may be very difficult to detect visually or with remote sensing techniques. Natural degradation rate for Bunker C is very slow, and it may persist on beaches for years.

Links: Unified Command