TPO 10 Integrated Writing Task The sea otter is a small mammal that lives in waters along the western coast of North America from California to Alaska When some sea otter populations off the Alaskan coast started rapidly declining a few years ago it c

The author, in the reading, describes environmental pollution as the most probable reason behind the decline of the sea otter population across the Alaskan coastal region. The speaker, in the listening, however contends the authors position, by providing evidence which explains how orca predation is the reason behind the decline in the sea otter population.

First of all, the author, in the reading, states that pollution seemed to be the more likely cause initially because there were known sources of it along the Alaskan coast, such as oil rigs and other sources of industrial chemical pollution, and water samples collected from this area revealed high levels of chemicals that could make such species vulnerable to life-threatening infections. The speaker, in the listening, however, states that ongoing investigation refutes the pollution hypothesis because there had been no dead sea otters washing off the shore as should have been had pollution been the major factor. On the other hand, this evidence is more consistent with the predator hypothesis.

Secondly, the author, in the reading, states that other species in the region, such as sea-lions and seals have also seen a decline in their population, indicating more evidence towards the environmental pollution hypothesis. He further states that only widely occurring predators such as the orca, could have had the same effect but orcas prefer to prey on whales. The speaker, in the listening, however disagrees with the author. She reveals that because of human hunting, whales have almost disappeared from the region, which might have caused the orcas to change their diet based on available resources. Orcas would then be preying on sea otters, sea-lions and seals.

Finally, the author, in the reading, believes that pollution hypothesis could also explain the uneven pattern of otter decline. However, the speaker, in the listening, counters the author, emphasizing that the uneven pattern can be better explained by the predation hypothesis. She goes on to say that orcas cannot access regions of shallow water and hence otter population in these regions would not decline.

To sum up, as is evident from this essay, the author, in the reading, and the speaker, in the listening, hold very different opinions on what caused the decline in sea otter population along the Alaskan coast.