Reserve Otter Monitoring Project (ROMP)

You may have seen otters frolicking in the ocean off Cannery Row in Monterey, but did you know that the Elkhorn Slough, home to more than 120 otters is the only estuary significantly colonized by southern sea otters? Equipped with spotting scopes and binoculars, volunteers for the Reserve Otter Monitoring Project (ROMP), monitor the number, locations, and activities of otters in Elkhorn Slough and Moss Landing Harbor.

A little history

ROMP began as an outgrowth of two years of marine mammal monitoring in support of the Reserve’s Tidal Wetland Project in 2011. These observations prompted a study of the otters in Yampah Creek in 2011. Two years later, collected data clearly demonstrated that the behavior of slough otters was significantly different from their coastal counterparts.

The analysis was presented to multiple organizations including scientists from the US Geological Survey, University of California-Santa Cruz, California Department of Fish and Wildlife, and Monterey Bay Aquarium. Based on findings, the group conducted a collaborative three-year study of otters in Elkhorn Slough. The study, the Elkhorn Slough Otter Project (ESOP), ran from September 2013 through September 2016. Following its conclusion and considering the value of the data, Reserve personnel decided to deploy volunteers to continue to monitor the entire slough indefinitely.

Why monitor otters?

The Elkhorn Slough is the only estuary significantly colonized by southern sea otters. Otters are key to the health of the ecosystem.

The objective of ROMP is to monitor the number, locations, and activities of otters in Elkhorn Slough. Volunteers complete at least two observations a month, stationed at various locations around the slough and at Moss Landing North Harbor. They identify otters as adults or pups and record their activities, such as resting, foraging, and grooming. While other researchers might conduct more intensive short-term studies of otters in Elkhorn Slough, the Reserve is committed to providing this backbone of consistent long-term observations.

ROMP observations provide insight into otter use of this estuarine environment which may provide guidance on identifying other similar environments suitable for otters. Variables that influence otter numbers and movements include:

  • Time of day
  • Tide
  • Time of year
  • Food availability
  • Human disturbances
  • Location of eelgrass beds
  • Availability of secluded creeks

How are the data used?

Data collected are readily available to other researchers so that they can apply their expertise to help determine the driving factors behind otter behavior. Data collected over an extended period of time could support a variety of studies such as examinations of population fluctuation, birth rates, carrying capacity of the slough, preferential areas for resting versus foraging, movement of otters in a day, etc.

The ROMP team is committed at a minimum, to reviewing broad trends in abundance over time at least once a month, with an overall summary once a year. Findings are reported in the volunteer newsletter and in the Reserve’s State of the Estuary report. Beyond this, additional analysis is conducted as needed to answer specific questions or contribute to publications and reports.