Both the reading passage and the lecture talks about the decline in the population of sea otters and the reason associated with it. The former is inclined towards the pollution hypothesis and gives three reasons to bolster it. However, the later talk about the predator hypothesis and opposes all three reasons mentions in the reading passage.
First of all, it is mentioned in the reading passage that the pollution is at its peak in the Alaskan coast because of oil rigs and various chemical pollutants let into water by the industry. Due to the increase of the dumping of pollutants in the water the chemical level is very high that is threatening the otter's population. However, the professor in the lecture contends this theory and mentions that if the otters die because of chemical pollution or the oil rigs then their bodies should be washed up at beaches, but there has been no traces of any bodies found at the beaches and that gives support to the predator hypothesis.
Second of all, the passage mentions the downfall of various sea mammals, this shows a correlation between the decrease of other sea mammals and sea otters and both focuses on the environmental pollution. The passage further mentions that environmental pollution occurs every species and compares it with the predator of whale, that is ocra. On the other hand, the professor in the lecture argues that, even though, ocra hunt whale currently a higher population of whales is being hunted by humans and there is less prey for the ocra to hunt. Due to the following circumstances ocra will be dependent on the sea otters.
Finally, the passage mentions that the spread of the sea otter and the downfall is not uniform. Some sea otters are stable, while some are not and the reasons for this according to the passage is ocean currents and other environmental factors. Nevertheless, like the two suggestions before, the professor in the lecture proclaims that the sea otter are being hunted by ocra and because of the large size of ocra they can't be in places with shallow water. This theory aligns with the fact that the population of sea otter is being decreased in deep waters and there is no effect on the population in the shallow water.