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In contrast to the reading passage, which supports the idea of contamination as the cause for the decreasing of sea otter’s population in northern Alaska, the lecturer emphasizes on the point that the predator’s attacks are the main reason for such event, thus, having a different point of view.
The passage explains that sea otter mortality’s rising is led by contamination resulting from oil rigs operating in the zone, additionally, the pattern of mortality, which is characterized with a high otter’s decreasing in some areas and almost nothing in another one results from the marine currents which concentrate the contaminants in some regions and causes the death to the mammals that live there. On the other hand, the professor refutes this point by noting that the otter’s death in this way will cause dead bodies to get to the coast, which is not happening now.
Professor states his hypothesis based on that the predators (like Orcas) are changing their diet mainly owing to the difficulty to get whales in the zone, the principal food for them. This difficulty has been contributed by the decreasing in whale’s population, as a consequence of the high levels of hunting executed by the human being. Thus, Orcas are killing otters and other little mammals in the absence of whales, additionally, the patterns of those behaviors are concentrated in zones where the orcas have access and are uneven in unreachable rocky areas.
To summarize, according to the lecturer, otter’s population decreasing is led by Orca’s diet changes and is supported by these facts: no dead bodies at the coast, orca’s difficulty to get whales in the area and pattern of otter’s population which is higher in orca’s inaccessible areas. The professor’s ideas contrasts and in some ways refutes the reading passage hypothesis of deaths caused by contamination.