On a crisp winter day in February, we set out on a small boat for a couple of Steller sea lion (Eumetopias jubatus) haulouts just 18 miles south of the Alaska SeaLife Center.
Our mission: to collect scat.
As we arrived at the first haul out, we took pictures of the sea lions present on the rock for our records before they were disturbed by our presence. Bundled up in full mustang survival suits and armed with plastic bags, trowels, and wet wipes, we jumped onto a rocky islet near Cape Resurrection.
We collect fresh scat samples between the months of January and May as this time period is believed to be most critical for survival and pregnancy. Analysis of the scat can tell us a number of things including: the frequency of occurrence of prey, whether or not the individual is pregnant, and the presence of stress hormones in relation to these factors. Collecting samples throughout the winter season can show seasonal changes in the sea lion diet and give us a better understanding of prey availability by location and interannual patterns.
It is important to know sea lion diet because nutritional stress combined with changing environmental pressures may limit population recovery for this endangered species. For example, as lipid-rich fish such as salmon and herring become less available, sea lions may opt for fish that are less fatty. Keeping an eye on the diet of sea lions during times of changing prey resources helps us understand how well sea lions adapt to fluctuations in their surroundings.
As I picked my way over the rock searching for fresh scat, the sea lions roared at us from the water. Each time I spotted a sample I encountered an unexpected hardship: my hands had gotten so cold (even with warm gloves underneath my plastic gloves) that I had a hard time simply opening the Ziploc bag! I felt quite silly struggling with a plastic bag, trying to command my fingers to work. When I would finally get it open, I would try to scoop up the entire sample and slip it into the bag that was flapping wildly in the wind. Inevitably, it was a bit of a messy process, but cross-contamination between samples would discredit the results. So carefully taking wet wipes I would wipe down the seal on the bag, the trowel and sometimes my gloves; anything that might have come in contact with the previous sample before starting a new sample. We collected around thirty samples this way.
I laughed to myself as I collected, remembering all of the “poop-scooping” jobs (dog walking and horse barns) I had in order to support myself through college. Who knew I would end up using my degree to collect the worst smelling fecal matter of all? The smell of sea lion scat is a horrific mix of week old sea food that has been left in an old gym bag to ripen. It hits you all at once, gags you, and makes it impossible to breath. It is not pleasant, but I wouldn’t trade it for the world. When I glanced up from my work, the whole mountain range surrounding Resurrection Bay lay before me, the winter sun barely touching the summits.
We made one more stop at Mary’s Bay, another haul out not too far away. We were just going to take a few pictures, but once we saw the amount of females and pups present we decided to hop ashore for just a few more samples.
The wind had shifted on the way home and the surf was extremely choppy. Those full mustang survival suits keep out the wind but they did not keep out the water! After the first few sprays of ice cold ocean water we could feel it soak into our bottom layers. It was going to be a long ride home. I have never been happier to see home as I was that day. We were completely drenched and frozen. Still, upon reflection in a hot shower, it was an amazing day of fecal collection, and I look forward to the next time. For now, there are samples to analyze.
{This research was conducted under NMFS Permit No. 18438-00}
Photo Credits: C. Brown & A. Bishop
Written by: Jennifer Goetsch
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