In the given case, the spilling of oil influenced many animals in Prince William Sound, Alaska. Due to spillage, many animals in the region comprising harbor seals, killer whales, fish, sea otters, and seabirds got influenced. It can be considered that genetic drift affected the gene pools of the organisms in the regions around the oil spill.
Variation in the relative frequency of different genotypes in a small populace, due to the chance desertion of specific genes as individuals do not reproduce or die is known as genetic drift.