Tuesday, February 21, 2012

Sea Otters and How They Affect the Ecosystem

Sea otters are well known for being adorable furry creatures that eat constantly while floating leisurely on their backs. They also are what we call keystone species that have great impact on their respective environments; these can be negative or positive but usually the latter. So how big of a negative impact could a constantly consuming lazy creature like the otter have on the environment? Massive. Sea Otters can eat upwards to 35% of their body weight on food. Most of their food sources come from other sea life that eats kelp. Kelp forests are vast and diverse ecosystems that many creatures use to breed, and breed very productively. There are fields of these kelp forests off California coast, and sea otters are also present as a result.

Sea otters keep these environments diverse and flourishing by eating a variety of sea life, such as crabs, sea urchins, lobster, etc. that keep the balance of the life cycle of sea life living in the kelp forests. Multiple times in history, humans have tried to take otters out of the ecosystem believing they were negatively effecting the environment because of their voracious appetite. Instead, humans did the exact opposite of what they were intending to accomplish. Humans thought that sea otters were eating too much of the fish that they themselves wanted to harvest, so they hunted sea otters to near record low levels. Sea urchin population exploded as a result because of the lack of sea otters that were their natural predators. As a result, the sea urchins ate vast quantities of kelp unchecked, destroying the habitat of many diverse breeds of fish who use it as a mating ground. Fish populations plummeted; the only way to counteract this was to bring back the keystone species, sea otters. Once they brought back the sea otters by protecting them and stop the hunting, the environment gradually recovered. An ecosystem is like a fine watch, you can’t take out a piece, no matter how small or apparently insignificant without damaging the whole thing. Sea otters are one example of what can happen when you take out a big piece.

Article:

http://www.otterproject.org/site/pp.asp?c=8pIKIYMIG&b=33677

http://www.exploringnature.org/db/detail.php?dbID=7&detID=77

Posted By Andy Zou (C)


6 comments:

  1. I took an ecology class last semester, and one of the most interesting topics in ecology, in my opinion, is the effects of keystone species on their environment. We can make predictions about what effects we think a certain species has, but until we observe the results of removing that species from their environment, we never really know the extent of the effects. I feel like humans, with an arrogant view of our own intelligence, make this mistake often. We see a lot of otters (or any species/predator) and we see the fish (their prey). Drawing a simple conclusion, we think - predator = + prey. But this neglects all the steps in the food chain in between that are not visible to the naked eye: the kelp forest, the microorganisms, intermediate levels of predators, and the chemical environment. I think realization of all the interconnectedness and and the unseen interactions that lie beneath the equilibrium of an ecosystem is essential to all the greater ecological applications (such as global warming, mass extinction, and habitat loss/fragementation) that are essential in science today.

    Posted by Laura Moro

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  2. In certain situations human interference can be for the better. Many endangered species have been taken off of that list because of human organizations to protect them. However, I think humans need to understand the basic pattern of evolution before they interfere in nature, however good their intentions might be. I think the main point of your blog is emphasizing the point that there is a bigger ripple effect on species than humans can anticipate. All that being said, I really wish I could eat 35% of my body weight in food!

    Published By Erica Bonnell

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  3. So true. We have to understand what and how our actions will affect the ecosystem before we do them. I think more often than not, what we do to the ecosystem are for our benefit and it clearly has a negative effect on the ecosystem.
    Unfortunately, because ecosystems are so huge and diverse, we cannot account or calculate all the possible scenarios that might happen if we do something to it; no matter how well we've come to understand it.

    -Hermann Kam

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  4. One thing I want to point out is that I believe it is lucky that we were just able to "bring back" sea otters. So often animals go extinct for various reasons, and when they do it effects the whole ecosystem. I believe things are they way they are for a reason. Sea otters would be naturally extinct if they weren't fit to be in the wild or didn't have a part in the food chain. But that is not the case. Situations like these, I feel like nature should be left to run its course. Humans should not interfere, it's not our place to.

    posted by Taylor Pirog

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  5. Sea otters are a very key keystone species on the west coast. They also used to be very abundant and some even existed on the east coast way back when. With their major predators being killer whales and sharks the population does seem to be kept under control nowadays. However humans killing off every one they see is absurd and a terrible idea. It's a miracle that they were able to save the species and bring the population back up to the level that it is at today.

    Posted by Nicco Ciccolini

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