Sea otter death….and life!

Sea otter with urchin Credit: matt knoth (Flickr)

Last fall, our class visited the sea otter researchers at the Monterey Bay Aquarium. Sandeep summarized many neat tidbits about otters from that trip on this blog. Two items that really piqued my interest involved otter mortality. In California, many otters die from disease or shark bite. What’s going on?

I tracked down the answer during my internship at KUSP 88.9 FM. Here’s a short radio story about how disease contributes to the recent otter population decline.

I talked about the increased number of shark bites during my interviews with Tim Tinker, an otter researcher for the U.S. Geological Survey, and Steve Shimek, executive director for The Otter Project, a non-profit organization working to support otter population recovery. The slideshow covers Tinker’s thoughts about the shark bites.

Shimek isn’t convinced that sharks only “taste” otters. Perhaps these toothy predators are swallowing them too. “What washes ashore is the otters that have been bitten and maybe spit out by the shark,” Shimek says. “Of course, we don’t know the number of otters that were eaten by the sharks because we’re never going to find those otters. Those otters are shark poop.”

Whether tasted or swallowed, the increased number of shark bites concerns otter advocates. Otter and shark biologists plan to work together to find the cause.

Tinker told me about another neat project comparing the environment and genetics of otter populations in Alaska, California and Canada. Of those three groups, only the California cluster is in decline. Researchers want to find similarities and differences between the three populations to help pinpoint the specific reasons for this downward trend. They set out for a three-week Alaskan expedition on Monday. It’s the second year of fieldwork on this project.

[UPDATE: Follow the scientists as they blog from the field here.]

The scientists will trap wild otters, collecting blood samples and one whisker for genetic analysis. The blood contains genetic markers that indicate otter immune system responses. These results will help them learn which diseases dominate each population.

The whisker contains clues to the otter’s diet over time — chemical elements unique to different kinds of prey. The tip of the whisker is several months older than its base. The scientists test many sections along its length to figure out an otter’s favorite treats. Many diseases start with a toxic meal, so this information helps scientists figure out which type of prey carries a poisoned punch.

Tinker hopes to have results from this long-term study in a couple of years. Until then, follow their work at the USGS Pacific Nearshore Project website.

I’ll end with happy otter news from SciCom’s backyard. A wild otter was born in Elkhorn Slough, a wetland south of Santa Cruz, last week. Researchers working on an unrelated project witnessed the birth and posted videos to YouTube. It’s hard to see the new pup, but it’s neat to watch the other otters form a ring of bodyguards (or babyguards?).

Description from press release:

This clip shows the mom/pup pair being noticed by a third otter, who then retrieves more otters to form a protective circle around the two.  Interesting points include:
0:00 – mother holding pup in the air to clean it
0:19 – the pair are noticed by a third otter, who seems excited at the new addition
0:49 – a new otter swims up
1:05 – another mom/pup pair joins in, then the three new otters disappear for a bit
2:52 – another otter returns briefly
3:30 – five otters begin to circle up

It’s a tough world out there, little otter, but know that scientists, environmentalists and SciCom slugs are looking out for you!