Description

Today sea otters are mostly known for being cute, cuddly, and lovable creatures as portrayed in this video.

However, during the time of the fur trade, they were more well known for having incredibly soft fur which was extremely popular for trading. Because their fur was so valuable, they were a focus for many hunters and traders. They were hunted so rigorously that they were eventually declared extirpated from BC waters. This means they were extinct in BC waters but still found in other areas of the world.

Not long after they were removed from the environment, other changes began to occur within the ecosystem. The tall kelp forests that provided shelter for so many animals began to disappear. A rapidly increasing population of sea urchins were found to be the cause of the disappearing kelp forests. Sea urchins commonly eat the kelp holdfasts, the part of the kelp that attaches to the ocean floor, which causes the kelp to float away afterwards. They only eat the holdfasts so they can quickly chew their way through entire forests.

In this video you can see what happens when sea urchins eat kelp holdfast off the Californian coast.

You may be wondering how sea urchins eating through entire kelp forests connects to the importance of sea otters and the fur trade?

Sea otters were actually one of the top predators of the sea urchins. They eat enough sea urchins to keep the population under control which ensures the sea urchins do not eat all of the kelp. Once the otters were removed from BC waters, the sea urchin population was able to rapidly increase and disturb the kelp forest ecosystem.

Recently, they have reintroduced sea otters to BC by relocating some from the Californian and Alaskan populations. These otters are now doing well in BC and help limit the urchin population once again which helps restore some of the kelp forests.

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Task

Why is it important that we be aware and prevent overharvesting of marine species?

Can you think of any more species that would negatively effect an ecosystem if removed?

These questions plus any other thoughts on otters or the impacts of species extinction on ecosystems can be answered in a discussion thread

Once you have made a submission for the assignment, your badge will appear the next time you log-in!  

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Learning Objectives

To understand the importance of balance in an ecosystem

To see how the relationship between animals, specifically predator and prey, is vital to the health of an ecosystem

To make connections between different ecosystems and species

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