Impact of Sea Otters on Community Ecology

Introduction Enhydra lutris is a marine mammal that can live a lifetime underwater. They are carnivorous and eat sea urchins, crabs, fish, mussels, and clams. They are called main species because they have a major impact on the marine ecosystem. Interactions between sea otters, sea urchins and algal forests have been studied as models of predator-prey interactions in community ecosystems.

One of sea otters' main food sources is sea urchins. Ecological release of the sea urchin population occurs when the hunter decreases the sea otter population. After that, sea urchin exploited seaweed which is their main food source, made sea urchin barren, seaweed was deprived of seaweed, but sea urchin was on the carpet. Sea urchin no longer eats food, and it is extinct in this area. In addition, because the kelp forest ecosystem is the habitat of many other species, loss of algae causes other cascade effects of secondary extinction.

Sea otters suppress the number of sea urchins and sea urchins suppress the growth of kelp. In the absence of sea otter, sea urchin eats all the seaweed and creates barren lands without seaweed. When the sea otters were reintroduced, the number of sea urchins decreased and a rich seaweed forest came back. Sea otter predators trigger an increase in kelp through double regulation. Are not you thinking that you are no longer creative and uncontrolled, or anything else you want? In that case, the expected quality may be hindered by others. If you want a higher quality than you need, you will not ignore the driving force that hinders you. You have to stop what is stopping you

Sea otters protect the algae forest from sea urchins. When the ocean of the North American West Coast was commercialized for fur, their number fell to such a low level - less than 1,000 in the North Pacific - they could not control the sea urchin population. In addition, sea urchins raise the robustness of kelp, so that most of the kelp forests and all species that depend on it have disappeared. Reintroduction of sea otter restored the ecology of kelp. For example, in the southeastern part of Alaska, about 400 sea otters have been released and they have grown to nearly 25,000 inhabitants.

Enhydra lutris are often cited as an example of an important species; they limit the density of sea urchins that eat kelp. When sea otters are removed from the system, sea urchins are grazed until the seaweed bed disappears, which greatly affects the community structure. For example, hunting of sea otters is thought to indirectly lead to extinction of Steller's manatee (Hydrodamalis gigas). The concept of key species has been widely used as a means of protection, but it has been criticized for the definition of its attitude towards operation. It is difficult to judge which kind plays an important role in each ecosystem experimentally. Furthermore, since the food network theory suggests that the main species is rare, it is not clear what the range of the main species model is.