TOEFL integrated writing: The sea otter

The reading presents the possible causes of declining of the sea otters population. According to the article the main reason for this species decreasing is water pollution. The professor has different opinion saying that the principal reason for sea otter decline is in fact predators.

In the article, the author sustain the pollution cause by bringing as an evidence the water samples collected from Alaska aria. The analysis of the water revealed an increased content of chemicals. The elevated level of chemicals in the water might have a negative impact on otter’s immune system causing indirectly their deaths. The professor refutes this point by saying that if the chemicals would cause the death of otters then corps of otters should be found along Alaskan shores. Since no dead otters were found, according to the professor the most probable cause of otter’s disappearance might be the predators.

Second, another argument enounced in the article to sustain the environmental pollution as cause for otter disappearance is that other marine mammal had encountered a decline in their numbers too. According to the article a similar effect upon sea species, can have big predators such as orcas but orcas prefer big mammals, for example whales. Hence, orcas are not hunting otters which are small animals so they couldn’t cause their decline. The professor contradicts this statement saying that whales disappeared too and orcas were forced to change their diet in order to survive and started to hunt otters. This fact contributed to the decreased of otters’ number from Alaska’s waters.

Third, the reading passage presents as a scientific explanation of an uneven pattern of otter decline the fact that the ocean currents and different environmental conditions produced inhomogeneous concentrations of pollutants along the coast. The professor contradicts this point of view explaining that the size of the orcas allowed them to hunt the otters which populated the large open spaces from the ocean and made inaccessible for hunting the rocky spaces. As a result, the otters who lived in these “closed” spaces survived and from here irregular decreasing number of otters in different areas.