Intern Take-Over: Our summer in the slough

Written by Annakate Clemons and Mason Emery


As keystone predators, the Southern Sea Otter (Enhydra lutris) plays a critical role in maintaining the stability and health of the ecosystem in which they live.

A trophic cascade discovered by Dr. Brent Hughes (Hughes et al. 2013) showed that there was an indirect positive effect of otters on eelgrass bed health. Elkhorn Slough eelgrass (Zostera marina) beds have been slowly recovering from a 10 hectare loss of eelgrass habitat following the construction of Moss Landing Harbor.


A good day on the slough, or any outdoor adventure for that matter, starts with protection from the elements—sunscreen, a hat, and multiple layers. Weather in the slough changes hour by hour. Many days start cold and foggy, with the fog casually burning off through the day, and then just as the sun graces you with its presence the wind picks up—making that extra layer you packed worth it. Pack a good lunch, sit back, observe and record. The greatest lesson we learned through planning these days is that timing is everything for kayaking in the slough, which we picked up on quickly through trial and error. We made the mistake of heading out early morning on the windiest of days and discovered that the usually mellow, lake-like water of the slough had become a rough and turbulent channel blanketed in whitecaps. As we struggled to stay in one place long enough to observe any otter, we watched as beached kayakers were rescued by boats and towed back in. We quickly called it quits, but as soon as we started battling our way back, my (AK Clemons) paddle snapped in half. I managed to power row myself back to the harbor after multiple attempts of trying to connect our kayaks. After that, we learned to check the wind forecast prior to going out in the field.


Restoration efforts of eelgrass habitat led by Kat Beheshti, PhD Candidate at UC Santa Cruz, have been widely successful. We joined Kat’s research team in early 2018 and participated in her 2018 restoration project. This year’s goal is to enhance restoration success via plot size while concurrently monitoring sea otter usage within the proximity of our newly transplanted plots.  We are interested in integrating the trophic cascade that Dr. Hughes discovered in the existing beds of Elkhorn Slough and apply it to our restoration plots to see whether there is the capacity for otters to enhance restoration success.


Our goal for this project is to assess sea otter activity in and around our 2018 restoration plots. Through observing otter activity in proximity to our plots, we hope to quantify the impact otters may have on restoration success. Otter activity that we are interested in includes: feeding, forage diving, mating, in transit, and whether otters present are mom and pup pairs. Proximity of the otter to the plot is recorded using a GPS. Our mode of transportation: kayaking. As project leads, we drafted a schedule with the goal of completing 40 hours of otter observations that span across all of our 2018 restoration plots. We organized a team of currently enrolled and recently graduated UCSC students to complete this task from June 2nd-16th.


Each field day includes four hours of otter observations. We arrived at the slough roughly two hours before high tide. That way we could let the rising tide carry us through the slough, easily reaching our furthest observation point by high tide. We could then turn back with the change of tide, allowing us to effortlessly glide back to the harbor, only occasionally being thwarted by the afternoon wind. Sampling in this way allowed us to record each area twice in a day, once on our way out and again on our way back in. This sampling method combined with the changing times of high tide from week to week allowed us to compile a record of otter behavior at various times of day—from early in the morning to early evening. We successfully designed a sampling protocol that would account for the temporal and spatial variability in sea otter usage in relation to our restored plots.

One of the most rewarding consequences of this work is our heightened understanding of the dynamics and structure of Elkhorn Slough. We witnessed massive algal production, learned where in the channel was the best to flow with the tide, expected the unexpected with the weather, and observed a variety of marine mammal activity throughout varying habitat types.

We’d like to thank Kat and the Wasson Lab for giving us this opportunity and for involving in their many slough projects!

Thank you for reading our blog post!

-Annakate Clemons & Mason Emery