Sea otters are voracious predators of sea urchins, which feed on kelp. When sea otters are present, they control the population of sea urchins and prevent them from overgrazing the kelp. This allows the kelp forest to thrive, which in turn benefits the entire ecosystem.
In addition to their role in maintaining kelp forests, sea otters also help to maintain the health of other coastal ecosystems, such as eelgrass beds and salt marshes. Sea otters also prey on other invertebrates, such as clams, mussels, and crabs. By controlling the population of these animals, sea otters help to keep the ecosystem in balance.
Sea otters are a keystone species, which means that they have a disproportionately large impact on their ecosystem relative to their abundance. Their presence is essential for the health of kelp forests and other coastal ecosystems.