Sea Otters decline

The reading and the lecture are both about sea otter decline. Sea otters are small mammals that live along the West Coast of North America from California to Alaska, playing an important role in the ecosystem. Initially, after the rapid decline of sea otters last year in Alaska, experts began to investigate the possible reasons and came out with two hypotheses: environmental pollution and predator attack. Experts believed that water pollution was likely to be the cause of sea otter decline because of the source of pollution in Alaska, and the increased levels of chemicals that showed up in the samples. Consequently, whatever was affecting the otters was affecting the other sea mammals. Additionally, environmental pollution usually affects the entire ecosystem, not only one species. More specifically it weakens their immune system, causing their deaths. However, the professor doubts that water pollution is causing the decline of the sea otter population. Since, if otters were being killed by pollution they would be found dead on the shore. On the other hand, if predators kill an otter, then it is eaten right away and since the otters are seldom found, which supports the predator hypothesis. Secondly, the scientists from the reading believed that the predator that causes the same decrease of otters is orcas although they usually hunt larger prey. Whereas, the professor mentioned that orcas prefer to hunt whales but whales have been decreased by human hunters. Since the otter and seals are smaller sea animals available in the area, orcas probably started haunting those more and created a decline. Finally, the reading claims that the pollution hypothesis explained the uneven pattern of otter decline. Also, the scientists highlight that other species in Alaska remained stable but this is due to the ocean current, or other environmental factors. This might have created uneven pollution concentration along the coast. Leading the decrease of otters.