September 2016 – Vol. 29 No. 1

Engaging Students by Monitoring Sand Crabs Through LiMPETS

Posted: Tuesday, May 5th, 2015

by Jeff Kepper

Engaging Students by Monitoring Sand Crabs through LiMPETS

Many visitors to California’s beaches have witnessed young children digging in the sand for an elusive creature, the sand crab or Emerita analoga. The sand crab is a crustacean related to crabs, shrimp and lobster that inhabits the area of the beach where waves break on the beach (Bryant, 2006). Sand crabs can be found surfing waves from Alaska to Chile (Jaramillo, Dugan, & Contreras, 2000). Emerita analoga is the ideal species to engage students through scientific research because of its presence on most beaches.

Field research offers opportunity for students to learn about science in a setting that is very different than the classroom (Hudak, 2003). It places student in “real” world setting that allows them to develop skill that are difficult to teach in the classroom (Lei, 2010; Switzer,1995). Participating in field research is a great way to increase learning, foster strong connections between participants, and engage students (Lei, 2010). With a minimal amount of equipment and training, young scientists can be introduced to field research, implement monitoring protocols, and participate in relevant scientific research on coastal ecosystems.

Long-Term Monitoring Program and Experiential Training for Students (LiMPETS)

LiMPETS was established in 2002 to introduce students to hands-on monitoring and scientific research. This program was designed to have students monitor coastal ecosystems of California Marine Sanctuaries. Monitoring programs are needed to establish baselines for abundance and distribution of organisms. It is difficult to determine if biodiversity is affected by natural or anthropocentric causes without sustained long-term monitoring (Addessi, 1994). By surveying smaller areas through transects, researchers can extrapolate their findings to the larger system (Holt et al., 2013). These baselines allow researchers to compare populations and make hypotheses about factors that might be affecting sand crab survival (LiMPETS, 2013). The aim of LiMPETS is to increase awareness and stewardship of sensitive coastal ecosystems. There are two LiMPETS monitoring programs: the rocky intertidal monitoring and the sandy beach monitoring. The sandy beach program focuses on Emerita analoga.

Monitoring Sand Crabs at Mission Beach in 2014

Classes from Helix Charter High School in La Mesa monitored sand crabs on two dates in the spring and fall of 2014 at South Mission Beach in San Diego, California. This was the first time that LiMPETS protocols were used to monitor this location. This beach was chosen based on the presence of sand crabs, safety (mild surf), and proximity to school. At the monitoring location students sample for sand crabs along a 10-meter transect that runs perpendicular to shoreline and into the surf. At each meter interval along the transect a core sample of sand is taken and sieved for sand crabs. Captured sand crabs are measured and their gender is determined. On two monitoring dates in 2014 the students captured 54 sand crabs in 100 cores (see Figure 1). Many of the captured sand crabs were smaller than 10 millimeters. The students expected to capture a greater number of larger sand crabs (over 10 millimeters). This was probably due to the number and size of sand crabs they practiced with in the classroom (see attached lesson). Even though their expectations were not met, most students thought that the experience of collecting data in the field was a worthwhile experience.

Figure 1. Graphs for monitoring sand crabs at South Mission Beach in 2014.

Figure 1. Graphs for monitoring sand crabs at South Mission Beach in 2014.

Students were asked after their field experience about monitoring sand crabs, and whether they would recommend the sand crab monitoring program to other students. The value of participating in LiMPETS programs can be seen from the following student comments:

“Besides the learning, it’s a great way to introduce science in a fun and entertaining way. It involves a lot of teamwork and patience. It also engages the students in science.”

“We were able to gather immediate information instead of waiting a couple of hours in the classrooms to get data. The field was more hands-on and interesting, but it was harder to get data at the beach. It is more difficult because the beach is always changing.”

“It was amazing! I thought that we were going to do a lot of hard work but it actually was so much fun it didn’t feel like work. It was more involved and detailed than I thought it was going to be.”



The experience in the field for students is very different than in the classroom. They really enjoy participating in science in a field setting. Several students that completed the monitoring last spring have asked to participate again this year on a Saturday. LiMPETS programs are a great way to get students engaged and excited about science.

Linked below is a lesson to prepare your students for LiMPETS sand crab monitoring. The lesson could be used with many different organisms. I have used bees, pill bugs, and hermit crabs for similar lessons. To learn more about LiMPETS and how to be trained for LiMPETS monitoring, visit the following website:

Monitoring Sand Crabs: An Inquiry Lesson for Secondary Students

The initial lessons for monitoring sand crabs provide the students with the information required to complete the monitoring protocols. The first anatomy lesson is designed to capture the students interest and help them generate questions that could be answered with further investigation. The activity is called, “I Notice, I Wonder”. In this activity, pairs of students are given a live sand crab to observe and record their observations. Making sound observations is an essential practice of science (Oguz-Unver & Yurumezoglu, 2009).

Lesson Background

Monitoring sand crabs requires young scientists to acquire the proper techniques of data collection. In this activity students will learn important anatomical features of sand crabs. They will also be trained on measuring carapace length and identifying gender of sand crabs.

Next Generation Science Standards for LiMPETS monitoring

HS-LS2 Ecosystems: Interactions, Energy, and Dynamics

HS-LS2-1. Use mathematical and/or computational representations to support explanations of factors that affect carrying capacity of ecosystems at different scales.

HS-LS2-2. Use mathematical representations to support and revise explanations based on evidence about factors affecting biodiversity and populations in ecosystems of different scales.

HS-LS2-7. Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.

HS-LS4-4 Biological Evolution: Unity and Diversity

HS-LS4-5. Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species.


  • Sand crabs (Instructor will need California Fish license or Collecting Permit to collect)
  • Magnifying glass or dissecting scope
  • Calipers (Individual calipers can be purchased at Harbor Freight Tools for $2.99 plus tax)
  • Sand crab practice cards (Available on LiMPETS website)


Students work in small groups with one live sand crab. Each student writes down observations about their sand crab (number of appendages, color, number of antennae, segments of body, how it moves, how it swims, etc.). The groups are then given a dissecting scope or hand lens and come up with additional observations. Once their initial observations are complete, the students draw their sand crab (see Figure 2). The student’s observations are shared with the class. Examples of the “I Notice” observations from the students included the following: size, movement or lack of movement, color, number of appendages, and method of movement.

Figure 2. “I Notice, I Wonder” sample student work.  Photograph by Kepper

Figure 2. “I Notice, I Wonder” sample student work.
Photograph by Kepper

After sharing their “I Notice” observations, students generate a minimum of three questions in the “I Wonder” portion of the activity. Questions are written on the far side of the paper opposite their observations. The questions facilitate the discussion on sand crab background. After the question and answer portion of the activity, each student labels anatomical features of sand crabs on their drawing (see Figure 3). The “I Notice, I Wonder” activity engages the students. They are free to use their curiosity and explore to make observations and generate questions. Their questions drive the discussion portion of the lesson. Students are asked to determine which “I Wonder” questions they could investigate scientifically. This lesson transitions into determining the sex and measuring the carapace or outer shell length of sand crabs.

Figure 3. Labeled student sketches of sand crabs.  Photograph by Kepper

Figure 3. Labeled student sketches of sand crabs.
Photograph by Kepper

Gender Identification and Measuring Exercise

One emphasis of the LiMPETS monitoring program is the proper collection of data. As students make observations in the “I Notice, I Wonder” lesson, they are introduced to the crab’s anatomical structure. This knowledge will be necessary for them to complete the monitoring process. Students have to learn how to correctly measure carapace length and determine the sex by locating the presence or absence of pleopods on sand crabs. Sand crab females have three pairs of pleopods to manage the eggs. Males do not possess pleopods. To practice determining sex and measuring carapace length, LiMPETS provides sand crab playing cards (see Figure 4). These cards allow students to practice measuring the standard lengths used in the monitoring protocols on one side of the card and sex determination on the other. Calipers are used to measure the standard length (which is the length of the carapace). By lifting the telson and locating the pleopods, sex can be determined (see Figure 3). Students work in groups, first identifying sex and measuring eight sand crabs on the practice cards, then repeating the process with five live sand crabs. All of their data are recorded in their practice data table (see Figure 5). By reviewing the student’s measurements, the instructor can determine which groups need additional practice. After this lesson, the students would learn the protocols for monitoring in the field.

Figure 4. Sample of practice cards used to measure carapace and determine gender. Photograph by LiMPETS

Figure 4. Sample of practice cards used to measure carapace and determine gender.
Photograph by LiMPETS

Figure 5. Practice data sheet for recording data from practice cards and five live samples.

Figure 5. Practice data sheet for recording data from practice cards and five live samples.


Addessi, L. (1994). Human disturbance and long-term changes on a rocky intertidal Community. Ecological Applications, 4 (4), 786-797.

Bryant, P. J. (2006). Pacific sand crab (mole crab), Emerita analoga. Natural History of Orange County, California, University of California, Irvine. Retrieved from

Holt, B. G., Rioja-Nieto, R., Aaron MacNeil, M., Lupton, J., Rahbek, C., & Peres-Neto, P. (2013). Comparing diversity data collected using a protocol designed for volunteers with results from a professional alternative. Methods in Ecology & Evolution, 4(4), 383-392.

Hudak, P. (2003). Campus field exercises for introductory geoscience courses. Journal of Geography, 102, 220-225.

Jaramillo, E., Dugan, J.E., Contreras, H. (2000). Abundance, tidal movement, population structure and burrowing rate of Emerita analoga (Anomura, Hippidae) at a dissipative and a reflective sandy beach in south central Chile. Marine Ecology, 21(2), 113–127.

Lei, S.A. (2010). Assessment practices of advanced field ecology courses. Education, 130(3), 404-415.

LiMPETS (2013) Long-term monitoring program and experiential training for students. Retrieved from

Oguz-Unver, A., & Yurumezoglu, K. (2009). A teaching strategy for developing the power of observation in science education. Online Submission.

Switzer, P.V. (1995). Campus field trips: An effective supplement to classroom instruction. Journal of College Science Teaching, 24, 140-143.

Jeff Kepper is a teacher at Helix Charter High School in La Mesa, CA and is a member of CSTA

Written by Guest Contributor

From time to time CSTA receives contributions from guest contributors. The opinions and views expressed by these contributors are not necessarily those of CSTA. By publishing these articles CSTA does not make any endorsements or statements of support of the author or their contribution, either explicit or implicit. All links to outside sources are subject to CSTA’s Disclaimer Policy:

One Response

  1. Hi Jeff – What a great article. I work for the LiMPETS program up in the San Francisco Bay area, and it is exciting to hear that you’ve had success implementing the monitoring program in southern California. I also really enjoyed reading about the “I Notice, I Wonder” activity that you developed to complement the monitoring activities.

    Hope you will stay involved with our monitoring network! All the best.

    – Amy

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California Science Assessment Update

Posted: Wednesday, October 12th, 2016

by Jessica Sawko

In June 2016 California submitted a waiver application to discontinue using the old CST (based on 1998 standards) and conduct two years of pilot and field tests (in spring 2017 and 2018, respectively) of the new science assessment designed to support our state’s current science standards (California Next Generation Science Standards (CA-NGSS) adopted in 2013). The waiver was requested because no student scores will be provided as a part of the pilot and field tests. The CDE received a response from the U.S. Department of Education (ED) on September 30, 2016, which provides the CDE the opportunity to resubmit a revised waiver request within 60 days. The CDE will be revising the waiver request and resubmitting as ED suggested.

At its October 2016 North/South Assessment meetings CDE confirmed that there will be no administration of the old CST in the spring of 2017. (An archive of the meeting is available at Learn More…

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

Some ways to celebrate the 100th anniversary of the National Park Service in your classroom

Posted: Thursday, September 22nd, 2016

by Carol Peterson

1) To celebrate the 100th anniversary of the National Park Service, Google has put together a collection of virtual tours combining 360-degree video, panoramic photos and expert narration. It’s called “The Hidden Worlds of the National Parks” and is accessible right from the browser. You can choose from one of five different locales, including the Kenai Fjords in Alaska and Bryce Canyon in Utah, and get a guided “tour” from a local park ranger. Each one has a few virtual vistas to explore, with documentary-style voiceovers and extra media hidden behind clickable thumbnails. Ideas are included for use in classrooms. Learn More…

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

2016 Award Recipients – Join CSTA in Honoring Their Accomplishments

Posted: Thursday, September 22nd, 2016

CSTA is pleased to announce the winners of the 2016 CSTA Awards for Distinguished Contributions, Margaret Nicholson Distinguished Service Award, 2014 and 2015 PAEMST-Science recipients from California, and the 2016 California PAEMST Finalists. The following individuals and organizations will be honored during the 2016 California Science Education Conference  on October 21- 23 in Palm Springs. This year’s group of awardees are truly outstanding. Please join us in congratulating them!

Margaret Nicholson Distinguished Service Award

John Keller

John Keller

The Margaret Nicholson Distinguished Service Award honors an individual who has made a significant contribution to science education in the state and who, through years of leadership and service, has truly made a positive impact on the quality of science teaching. This year’s recipient is John Keller, Ph.D. Dr. Keller is Associate Professor, Cal Poly San Luis Obispo and Co-Director, Center for Engineering, Science, and Mathematics Education, Cal Poly San Luis Obispo. In her letter of recommendation, SDSU science education faculty and former CSTA board member Donna Ross wrote: “He brings people together who share the desire to make a difference in the development and implementation of programs for science teaching. Examples of these projects include the Math and Science Teaching Initiative (MSTI), Noyce Scholars Program, Western Regional Noyce Initiative, and the Science Teacher and Researcher (STAR) program.” Through his work, he has had a dramatic impact on science teacher education, both preservice and in-service, in California, the region, and the country. He developed and implemented the STEM Teacher and Researcher Program which aims to produce excellent K-12 STEM teachers by providing aspiring teachers with opportunities to do authentic research while helping them translate their research experience into classroom practice. SFSU faculty member Larry Horvath said it best in his letter:“John Keller exemplifies the best aspects of a scientist, science educator, and mentor. His contributions to science education in the state of California are varied, significant, and I am sure will continue well into the future.” Learn More…

Written by California Science Teachers Association

California Science Teachers Association

CSTA represents science educators statewide—in every science discipline at every grade level, Kindergarten through University.

NGSS: Making Your Life Easier

Posted: Tuesday, September 20th, 2016

by Peter A’hearn

Wait… What?

NGSS is a big shift. Teachers need to learn new content, figure out how this whole engineering thing relates to science, and develop new unit and lesson plans. How could NGSS possibly make life easier?

The idea that NGSS could make our lives easier came to me during the California State NGSS Rollout #1 Classroom Example lesson on chromatography. I have since done this lesson with high school chemistry students and it made me think back to having my own students do chromatography. I spent lots of time preparing to make sure the experiment went well and achieved the “correct” result. I pre-prepared the solutions and organized and prepped the materials. I re-wrote and re-wrote again the procedure so there was no way a kid could get it wrong. I spent 20 minutes before the lab modeling all of the steps in class, so there was no way to do it wrong. Except that it turns out there were many. Learn More…

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Written by Peter AHearn

Peter AHearn

Peter A’Hearn is the K-12 science specialist in the Palm Springs Unified School District and is Region 4 Director for CSTA.

Celestial Highlights, September 2016

Posted: Tuesday, September 20th, 2016

by Robert C. Victor. Twilight sky maps by Robert D. Miller. Graph of evening planet setting times by Dr. Jeffrey L. Hunt 

Our evening twilight chart for September, depicting the sky about 40 minutes after sunset from SoCal, shows brilliant Venus remaining low, creeping from W to WSW and gaining a little altitude as the month progresses. Its close encounter within 2.5° N of Spica on Sept. 18 is best seen with binoculars to catch the star low in bright twilight. The brightest stars in the evening sky are golden Arcturus descending in the west, and blue-white Vega passing just north of overhead. Look for Altair and Deneb completing the Summer Triangle with Vega. The triangle of Mars-Saturn-Antares expands as Mars seems to hold nearly stationary in SSW as the month progresses, while Saturn and Antares slink off to the SW. Learn More…

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Written by Robert Victor

Robert Victor

Robert C. Victor was Staff Astronomer at Abrams Planetarium, Michigan State University. He is now retired and enjoys providing skywatching opportunities for school children in and around Palm Springs, CA. Robert is a member of CSTA.