Sea otters are a small mammal that lives in the waters along North America's west coast from California to Alaska.

The reading and the lecture are both about the cause of decline in population of the sea otters. The article states that pollution is the main reason behind their decline in population whereas, the lecture explains that the main reason behind this is the predator hypothesis. First, the reading claims that pollution caused due to increase in harmful chemical concentration from the oil rings along the Alaskan Coast weakened the immune system of the sea otters, thus resulting in their death. However, the lecturer refutes this point by saying that the lack of dead sea otters near the sea beach indicates that they might have been eaten by predators and have not died from any infection. Secondly, the article shows that there has been a decline in the population of other sea mammals like the sea also, indicating that pollution might have affected the entire ecosystem instead of just one species. Nevertheless, the lectures rebutted this point by saying that the population of sea whales decreased due to human hunting and after a shift in their population workers, might have changed their diet and started hunting other small sea mammals like otters and seals, thus, in turn, decreasing their population also. Finally, the reading claims that ocean currents or other environmental factors might have resulted in uneven pollutants along the coast thus declining the population of the sea otters in an unlikely manner. The professor opposes this point by saying that this uneven pattern in decline of the otter population was not because of pollution but because of predators. Places where the predators could not reach easily (for example shallow water),showed an increase in population of the sea otters as compared to other places which are easily accessible by the hunters.