Remember the oil spill in Ventura three weeks ago? In some ways, it didn’t seem so bad: an estimated 29,400 gallons of oil spilled, but the oil was contained before it reached the ocean. Now, that number is estimated at 45,000 gallons with more than 150 workers cleaning up the oil. The cleanup operation is predicted to take several more weeks. The pipeline, meanwhile, has been turned back on.

For residents in the area, noxious fumes have been reported to cause headaches and other discomfort. According to the Department of Fish and Wildlife, the wildlife casualties near the spill have been: rats, a gopher snake, a raccoon and a rabbit. The fact that the oil was contained before reaching the ocean likely saved a significant amount of wildlife.

But how effective are oil spill cleanups, especially when those spills occur in the ocean?

The answer, according to a report in Hakai Magazine and Smithsonian.com, is that cleanups don’t do much for birds and other marine animals at all. While containment of oil is beneficial, it is very difficult. Yet containing the oil is the only way to prevent more birds from being covered in oil—a crucial step, given that the average post-treatment survival rate of birds that have been oiled is still less than one percent.

“Oiled birds have an extremely low survival rate, but it can depend some on the species” added Kerry Wilcox, the Program Manager at the Richardson Bay Audubon Center and Sanctuary. “For example, the effort can make a difference for Penguins, but for Scoters the process is usually too stressful.”

Wilcox, who also worked on recovery efforts during the 2007 Cosco Busan spill in the San Francisco Bay, stressed that even a thin layer of oil in the water can cause damage, making containment extremely important. Although containment strategies can be effective in smaller marine spills or in spills on land like the one in Ventura, containment is less reliable in larger scale marine disasters—underscoring the importance of preventing such accidents rather than responding.