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Friday Finds: Sea Otters Keep Seas Squeaky Clean

Sea otters regularly draw crowds at aquariums and along shorelines for their famously cute mustaches and furry bodies, but recent research shows that these little starlets should really be applauded for their ability to keep algae from mucking up our oceans.

According to researcher Brent Hughes from the University of California, Santa Cruz, sea otters’ appetite for crab inadvertently helps keep algae growth in check by protecting algae-eaters like orange sea slugs and isopods, which crabs love to eat. The more crabs that sea otters eat, the fewer there are to go after sea slugs and isopods, who are then free to munch on as much algae as they like. This algae-restricting freebee is a big boon to oceans and those who love them given that our waterways are regularly plagued with slimy green algae created by an influx of nitrogen and phosphorus runoff from agricultural pollution and sewage. If you want to see what I mean, just take a look at the green slime situation that regularly fouls Florida waterways

Of course, sea otters aren’t the only creatures that are the defining players in a nature-sponsored chain reaction known as a “trophic cascade.” It’s well known that wolves and grizzly bears also have huge effects on the food chain and their surrounding environments just by existing. But this recent study shows that fuzzy little creatures like sea otters can have the same effect as large, apex predators known as keystone species. And, it’s just the latest study to find that sea otters bring all kinds of benefits to our ocean ecosystems. For example, sea otters’ love for urchins and other invertebrates helps keep populations in check and prevents these creatures from mowing down kelp forest habitat.
Despite their ecosystem benefits, sea otters were hunted almost to extinction during the fur craze of the 19th and 20th centuries. Recently though, they’ve started making a comeback thanks to a hunting ban and conservation efforts. In fact, sea otters have been doing so well that for years the U.S. Fish and Wildlife Service has had an odd relocation policy that moves sea otters from their southern California habitat to San Nicolas Island in an effort to appease the fishing industry, which doesn’t like the resource competition that sea otters bring to the table. The government agency recently nixed that backwards policy, and in late July Earthjustice stepped in to defend the government’s decision against several industry fishing groups.
Says Earthjustice attorney Andrea Treece, who is representing the coalition:

We should celebrate that California sea otters have a chance at repopulating our coast and contributing to the health of kelp forests. Rather than waste its resources on a program that wasn’t working, the Fish and Wildlife Service made the only sensible and lawful decision to allow otters to go where they need to go to eat, mate, and raise their young.

Source: National Geographic, "Sea Otters: Your Defence Against the Algal Apocalypse

Tags:  Friday Finds, Oceans