Over the decade there has been a decline in Aleutian sea otters. The disappearance of the otters has greatly affected the ecosystem and the local food web. Without them, sea urchin populations have soared, resulting in the harm of coral reefs. Climate change has also played a big role in harming the reefs, and spikes in carbon dioxide could acidify oceans. andAnd warmer temperatures have increased animal metabolism. Otter declination has happened in the past when fur traders in the 18th-19th centuries had almost eradicated them by overhunting, which led to the problems we have today. Though they were later fixed when hunting was restricted., Dr. Estes, an American ecologist, has suspected that the disappearance of the otters could result from the starving orcas that were perhaps deprived of their preferred prey by industrial whaling and have turned to eateating otters in desperation, to which they can eat an excessive amount of. For that reason, it could become hard to sustain the otter populations.