SIMoN
  Sanctuary Integrated Monitoring Network
Monitoring Project

LiMPETS sandy beach monitoring

Principal Investigator(s)

  • Abby Nickels
    Greater Farallones Association
  • Emily Gottlieb
    Pacific Grove Museum of Natural History
  • Jessie Altstatt
    Channel Islands National Marine Sanctuary
  • Monika Krach
    Greater Farallones Association
Start Date: June 01, 1999

LiMPETS (Long-term Monitoring Program and Experiential Training for Students) is a citizen science program for students, educators and volunteer groups. Citizen scientists monitor the coastal ecosystems of California’s national marine sanctuaries, increasing awareness and stewardship of these important areas. The statewide program connects over 5,000 citizens (primarily teachers and students) annually to the ocean, involves them directly in a hands-on scientific endeavor and increases their knowledge of the marine environment, creating a new generation of informed and engaged ocean stewards.

Beyond the educational value of the program, the power of LiMPETS lies in the large quantity of data collected at more than 60 sites and over 600 miles of California coastline. Annually, thousands of people collect baseline data. By monitoring, teachers, their students and community groups become the eyes and ears for our coastal beaches and rocky shores detecting changes and possible problems. LiMPETS data has informed Monterey Bay National Marine Sanctuary’s Condition Report, was published in the National Marine Sanctuary Conservation Series, and helped establish a baseline of key indicator species for the new system of California Marine Protected Areas (MPAs).

The LiMPETS network is a collaborative effort among California’s national marine sanctuaries, Greater Farallones Association, and Pacific Grove Museum of Natural History. Together, we have established a long-term, quantitative intertidal and sandy beach program that can be used by the national marine sanctuaries, teachers, students, scientists, and resource managers to better assess the health of these habitats.

Visit http://limpets.org for more information.

Summary to Date

Sandy beach monitoring focuses on the Pacific mole crab (Emerita analoga), or sand crab, a common and abundant inhabitant. Sand crabs are a vital link in the sandy beach food web, feeding primarily on small, drifting plant plankton. They are prey for coastal birds, sea otters, and fishes. Sand crabs are used by humans as bait for fishing and have been used as indicators of the pesticide DDT and the neurotoxin domoic acid. The sand crab is also an intermediate host for a number of parasites, including acanthocephalans (thorny-headed worms) that affect threatened sea otters and surf scoters.

LiMPETS monitors 45 sandy beach sites along the California coast. The frequency of monitoring varies by site. At sites where data are collected frequently, sand crab abundance correlates with El Nino intensity (see Figures and Images).

In 2014-2016, LiMPETS worked with scientific experts to improve its science protocols, quality assurance and control practices, and database management. Following the recommendations of leading sandy beach ecologists along the west coast, LiMPETS altered its monitoring protocols in 2016 to reflect advancement of our scientific understanding of shifting beach dynamics. These protocol changes are accompanied by a new database and the LiMPETS Quality Assurance Project Plan. These enhancements greatly improves our ability to distinguish high-quality data and provide data confidence to scientists and resource managers.

Monitoring Trends

  • At sites where data are collected frequently (over 20 times a year), sand crab abundance correlates with El Nino intensity (see Figures and Images).

Study Parameters

  • Dispersal & Recruitment
  • Habitat association
  • Abundance
  • Distribution

Study Methods

LiMPETS collects abundance data on the Pacific mole crab (Emerita analoga) using a method modified from Dr. Jenny Dugan’s (UCSB) sandy beach monitoring protocols. Transect lines are set in the swash zone at monitoring locations, and students take cores at intervals from the top to the bottom of the swash zone (or to the deepest point students can sample safely). Sand crabs within these samples are measured and sexed before being returned to the swash zone.

With the advisement of sandy beach ecologists, LiMPETS altered its monitoring protocols in 2016 to reflect advancement of our scientific understanding of shifting beach dynamics. This includes adoption of an adaptive sampling approach and simultaneous sampling of cores along the transect line.


Figures and Images

Figure 1. Teachers learn and practice sandy beach monitoring protocols in San Francisco during a Teacher Workshop, part of the LiMPETS professional development series for teachers (photo credit: Monika Krach, Greater Farallones Association, 2016).


Figure 2. Krach, Monika. 2016. Increases in Pacific mole crab (Emerita analoga) abundance on Ocean Beach correlates to strong El Nino. Beyond the Golden Gate Research Symposium. San Francisco.


Figure 3. Krach, Monika. 2016. Increases in Pacific mole crab (Emerita analoga) abundance on Ocean Beach correlates to strong El Nino. Beyond the Golden Gate Research Symposium. San Francisco.