Local
6:00 am
Thu September 26, 2013

Researchers Explore Unknown Life of Otters in the Slough

Dr. Mike Murray of the Monterey Bay Aquarium preps a sea otter for surgery.
Credit Krista Almanzan

If you’ve ever filled out that line on your tax form to donate to the California Sea Otter Fund, your dollars are at work right now in Elkhorn Slough.   The fund is paying for the first year of a three year study on otters at the Moss Landing estuary. 

In a parking lot deep in Elkhorn Slough, researchers push a wooden box on wheels. Inside is a male sea otter just taken from the nearby waters.  Within minutes he’s weighed, sedated and laid out on the surgery table in a mobile vet clinic.  Standing by in surgical scrubs is Dr. Mike Murray.  He’s the Director of Veterinary Services at the Monterey Bay Aquarium.  This is just one of 20 sea otters Dr. Murray will implant with a radio transmitter to help give researchers a better understanding of otters in the estuary.

Dr. Murray has already operated on and released more than a dozen of the Elkhorn Slough otters.  And at first blush, he’s noticed they differ from those living nearby in the open ocean where he says the otters have limited resources.  “So they tend to be a little bit thinner because there’s not as much grocery available. The animals we’ve handled so far here in the slough are big, well fleshed.  They are not suffering from inadequate grocery consumption,” said Dr. Murray.  It’s a notable observation since very little is known about the otters that live here in the estuary. 

More than a century ago, the fur trade decimated the California sea otter population.  In fact, they were thought to be extinct until about 50 were discovered off the Big Sur Coast back in the 1930s.  Since then the population has slowly grown to nearly 3,000.  Most live in the open ocean, but about 15 years ago, otters were found living in Elkhorn Slough, and their population here has grown ever since.  Dr. Tim Tinker is with the US Geological Survey and UC Santa Cruz.  He says it’s quite possible that some otters live here exclusively.   “If it is that sort of changes our whole view of the biology of sea otters. We sort of think of them as this open ocean species, but maybe they actually have a completely other persona that is a top predator in enclosed estuaries,” said Dr. Tinker.

Dr. Tinker is the principal investigator on this three year study that will look at how the otters use the slough and what effect they have on the habitat.  “We now realize that in fact this type of estuary might be critical habitat for sea otters.  That’s not something we were thinking in the past,” said Dr.Tinker.  If the slough does turn out to be critical habitat for the sea otters then this three year study will help policy makers determine if any steps need to be taken to protect the endangered animal.  “It will advise what areas are put under special protection here in Elkhorn Slough because sea otters are a listed species under the endangered species act.  That carries certain types of legal requirements and protections,” said Dr. Tinker.  Dr. Tinker says as the sea ott er population grows, it’s possible that they’ll start moving into other estuaries throughout California. This study may help scientists know what to expect if they do.