The reading passage and the lecturer discuss the reasons for a decline in the sea otter population The writer states that it is more likely that environmental pollution is the cause of the decline The lecturer disagrees with this point of view and claims

The reading passage and the lecturer discuss the reasons of declining the sea otters – small mammals from the western coast of North America. The writer states it is more likely that environmental pollution is the reason of its declining. The speaker doesn’t agree with this point of view and sure that attacks by predators caused such effect.
First of all, the article states that the first reason of declining is industrial chemical pollution. A high level of chemicals leaded to decrease resistance to infections of the otters. That is why it is the reason of their death. The lecturer does not agree with this statement and argues that there were no dead bodies across the coast. Thus the cause of declining is attacks by predators. They ate the otters that is why those bodies were not found.
Secondly, the reading passage mentions the declining of seals and sea lions, which is one of the prove that pollution has affected all ecosystem, not only the sea otters. The speaker, on the other hand, states that people in this region began to hunt more actively, and the predators did not have enough food for themselves. So they had to change their diet and started to eat seals and sea lions, that is why this species declined too.
Finally, the whiter claims that the cause of uneven decrease of the otters is the pollution too. The concentration of the pollutants is various in different parts of the coast, and the declining of the otter is various too. The lecturer also disagrees with it and explains that predators are too large, they need space for hunting. They could not hunt in shallow or rocky locations, so this is the reason why the population did not decline there.