September/October 2017 – Vol. 30 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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State Schools Chief Tom Torlakson Announces 2017 Finalists for Presidential Awards for Excellence in Mathematics and Science Teaching

Posted: Wednesday, September 20th, 2017

SACRAMENTO—State Superintendent of Public Instruction Tom Torlakson today nominated eight exceptional secondary mathematics and science teachers as California finalists for the 2017 Presidential Awards for Excellence in Mathematics and Science Teaching (PAEMST).

“These teachers are dedicated and accomplished individuals whose innovative teaching styles prepare our students for 21st century careers and college and develop them into the designers and inventors of the future,” Torlakson said. “They rank among the finest in their profession and also serve as wonderful mentors and role models.”

The California Department of Education (CDE) partners annually with the California Science Teachers Association and the California Mathematics Council to recruit and select nominees for the PAEMST program—the highest recognition in the nation for a mathematics or science teacher. The Science Finalists will be recognized at the CSTA Awards Luncheon on Saturday, October 14, 2017. 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.

Thriving in a Time of Change

Posted: Wednesday, September 13th, 2017

by Jill Grace

By the time this message is posted online, most schools across California will have been in session for at least a month (if not longer, and hat tip to that bunch!). Long enough to get a good sense of who the kids in your classroom are and to get into that groove and momentum of the daily flow of teaching. It’s also very likely that for many of you who weren’t a part of a large grant initiative or in a district that set wheels in motion sooner, this is the first year you will really try to shift instruction to align to the Next Generation Science Standards (NGSS). I’m not going to lie to you, it’s a challenging year – change is hard. Change is even harder when there’s not a playbook to go by.  But as someone who has had the very great privilege of walking alongside teachers going through that change for the past two years and being able to glimpse at what this looks like for different demographics across that state, there are three things I hope you will hold on to. These are things I have come to learn will overshadow the challenge: a growth mindset will get you far, one is a very powerful number, and it’s about the kids. Learn More…

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Written by Jill Grace

Jill Grace

Jill Grace is a Regional Director for the K-12 Alliance and is President of CSTA.

If You Are Not Teaching Science Then You Are Not Teaching Common Core

Posted: Thursday, August 31st, 2017

by Peter A’Hearn 

“Science and Social Studies can be taught for the last half hour of the day on Fridays”

– Elementary school principal

Anyone concerned with the teaching of science in elementary school is keenly aware of the problem of time. Kids need to learn to read, and learning to read takes time, nobody disputes that. So Common Core ELA can seem like the enemy of science. This was a big concern to me as I started looking at the curriculum that my district had adopted for Common Core ELA. I’ve been through those years where teachers are learning a new curriculum, and know first-hand how a new curriculum can become the focus of attention- sucking all the air out of the room. Learn More…

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Written by Peter AHearn

Peter AHearn

Peter A’Hearn is the Region 4 Director for CSTA.

Tools for Creating NGSS Standards Based Lessons

Posted: Tuesday, August 29th, 2017

by Elizabeth Cooke

Think back on your own experiences with learning science in school. Were you required to memorize disjointed facts without understanding the concepts?

Science Education Background

In the past, science education focused on rote memorization and learning disjointed ideas. Elementary and secondary students in today’s science classes are fortunate now that science instruction has shifted from students demonstrating what they know to students demonstrating how they are able to apply their knowledge. Science education that reflects the Next Generation Science Standards challenges students to conduct investigations. As students explore phenomena and discrepant events they engage in academic discourse guided by focus questions from their teachers or student generated questions of that arise from analyzing data and creating and revising models that explain natural phenomena. Learn More…

Written by Elizabeth Cooke

Elizabeth Cooke

Elizabeth Cooke teaches TK-5 science at Markham Elementary in the Oakland Unified School District, is an NGSS Early Implementer, and is CSTA’s Secretary.

News and Happenings in CSTA’s Region 1 – Fall 2017

Posted: Tuesday, August 29th, 2017

by Marian Murphy-Shaw


This month I was fortunate enough to hear about some new topics to share with our entire region. Some of you may access the online or newsletter options, others may attend events in person that are nearer to you. Long time CSTA member and environmental science educator Mike Roa is well known to North Bay Area teachers for his volunteer work sharing events and resources. In this month’s Region 1 updates I am happy to make a few of the options Mike offers available to our region. Learn More…

Written by Marian Murphy-Shaw

Marian Murphy-Shaw

Marian Murphy-Shaw is the student services director at Siskiyou County Office of Education and is CSTA’s Region 1 Director and chair of CSTA’s Policy Committee.