reduction of sea otter population

The reading states that the most likely hypothesis to explain the reduction of sea otter population is environmental pollution and provides three reasons of support. However, the professor explains that predators have triggered the decreasing pattern of this animal and refutes each of the author's claims.

First, the article claims that sea otters have decreased due to pollution. Because scientists encountered a chemical along the Alaskan coast from water samples, they have said that pollution has provoked this problem in the coastal ecosystem. The professor refutes this point by saying that this hypothesis lack of support. He states that if pollution were the detrimental factor, animals could be seen dead on the beaches. However, no remains of this animal have been left. Therefore, the most probably explanation has to be predators which did not let any leftover of animals in the Alaska coast.

Second, the article posits that other small mammals have diminished also, such as sea lions and seals. Thus, pollution has affected the entire ecosystem triggering a complete reduction of mammals instead of affecting a single species. Moreover, the reading mentions that Orcas are not the problem because they prefer to eat large animals like whales. However, the professor says that humans have caused the reduction of whales’ population, so Orcas are forced to change their hunt habits of large animals to small mammals.

Third, the reading says that the pollution theory clearly explains the unstable pattern of otter decline. Moreover, it says that sea otters are stable in some areas, while in other places the population has decreased, so the environmental factor and ocean currents have provoked the uneven concentration of otters. The professor opposes to this point by saying that uneven patter theory is better explained by predator hypothesis. According to the professor, the population of sea otters has been minimized in places easy to reach for whales. Nevertheless, the population remains steady in shallow water where whales cannot go easily.