May/June 2017 – Vol. 29 No. 7

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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Participate in Chemistry Education Research Study, Earn $500-800 Dollars!

Posted: Tuesday, May 9th, 2017

WestEd, a non-profit educational research agency, has been funded by the US Department of Education to test a new molecular modeling kit, Happy Atoms. Happy Atoms is an interactive chemistry learning experience that consists of a set of physical atoms that connect magnetically to form molecules, and an app that uses image recognition to identify the molecules that you create with the set. WestEd is conducting a study around the effectiveness of using Happy Atoms in the classroom, and we are looking for high school chemistry teachers in California to participate.

As part of the study, teachers will be randomly assigned to either the treatment group (who uses Happy Atoms) or the control group (who uses Happy Atoms at a later date). Teachers in the treatment group will be asked to use the Happy Atoms set in their classrooms for 5 lessons over the course of the fall 2017 semester. Students will complete pre- and post-assessments and surveys around their chemistry content knowledge and beliefs about learning chemistry. WestEd will provide access to all teacher materials, teacher training, and student materials needed to participate.

Participating teachers will receive a stipend of $500-800. You can read more information about the study here:

Please contact Rosanne Luu at or 650.381.6432 if you are interested in participating in this opportunity, or if you have any questions!

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.

2018 Science Instructional Materials Adoption Reviewer Application

Posted: Monday, May 8th, 2017

The California Department of Education and State Board of Education are now accepting applications for reviewers for the 2018 Science Instructional Materials Adoption. The application deadline is 3:00 pm, July 21, 2017. The application is comprehensive, so don’t wait until the last minute to apply.

On Tuesday, May 9, 2017, State Superintendent Tom Torlakson forwarded this recruitment letter to county and district superintendents and charter school administrators.

Review panel members will evaluate instructional materials for use in kindergarten through grade eight, inclusive, that are aligned with the California Next Generation Science Content Standards for California Public Schools (CA NGSS). 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.

Lessons Learned from the NGSS Early Implementer Districts

Posted: Monday, May 8th, 2017

On March 31, 2017, Achieve released two documents examining some lessons learned from the California K-8 Early Implementation Initiative. The initiative began in August 2014 and was developed by the K-12 Alliance at WestEd, with close collaborative input on its design and objectives from the State Board of Education, the California Department of Education, and Achieve.

Eight (8) traditional school districts and two (2) charter management organizations were selected to participate in the initiative, becoming the first districts in California to implement the Next Generation Science Standards (NGSS). Those districts included Galt Joint Union Elementary, Kings Canyon Joint Unified, Lakeside Union, Oakland Unified, Palm Springs Unified, San Diego Unified, Tracy Joint Unified, Vista Unified, Aspire, and High Tech High.

To more closely examine some of the early successes and challenges experienced by the Early Implementer LEAs, Achieve interviewed nine of the ten participating districts and compiled that information into two resources, focusing primarily on professional learning and instructional materials. 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.

Using Online Simulations to Support the NGSS in Middle School Classrooms

Posted: Monday, May 8th, 2017

by Lesley Gates, Loren Nikkel, and Kambria Eastham

Middle school teachers in Kings Canyon Unified School District (KCUSD), a CA NGSS K-8 Early Implementation Initiative district, have been diligently working on transitioning to the Next Generation Science Standards (NGSS) integrated model for middle school. This year, the teachers focused on building their own knowledge of the Science and Engineering Practices (SEPs). They have been gathering and sharing ideas at monthly collaborative meetings as to how to make sure their students are not just learning about science but that they are actually doing science in their classrooms. Students should be planning and carrying out investigations to gather data for analysis in order to construct explanations. This is best done through hands-on lab experiments. Experimental work is such an important part of the learning of science and education research shows that students learn better and retain more when they are active through inquiry, investigation, and application. A Framework for K-12 Science Education (2011) notes, “…learning about science and engineering involves integration of the knowledge of scientific explanations (i.e., content knowledge) and the practices needed to engage in scientific inquiry and engineering design. Thus the framework seeks to illustrate how knowledge and practice must be intertwined in designing learning experiences in K-12 Science Education” (pg. 11).

Many middle school teachers in KCUSD are facing challenges as they begin implementing these student-driven, inquiry-based NGSS science experiences in their classrooms. First, many of the middle school classrooms at our K-8 school sites are not designed as science labs. Learn More…

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Written by NGSS Early Implementer

NGSS Early Implementer

In 2015 CSTA began to publish a series of articles written by teachers participating in the NGSS Early Implementation Initiative. This article was written by an educator(s) participating in the initiative. CSTA thanks them for their contributions and for sharing their experience with the science teaching community.

Celestial Highlights: May – July 2017

Posted: Monday, May 8th, 2017

May Through July 2017 with Web Resources for the Solar Eclipse of August 21, 2017

by Robert C. Victor. Twilight sky maps by Robert D. Miller. Graphs of planet rising and setting times by Jeffrey L. Hunt.

In spring and summer 2017, Jupiter is the most prominent “star” in the evening sky, and Venus, even brighter, rules the morning. By mid-June, Saturn rises at a convenient evening hour, allowing both giant planets to be viewed well in early evening until Jupiter sinks low in late September. The Moon is always a crescent in its monthly encounters with Venus, but is full whenever it appears near Jupiter or Saturn in the eastern evening sky opposite the Sun. (In 2017, Full Moon is near Jupiter in April, Saturn in June.) At intervals of 27-28 days thereafter, the Moon appears at a progressively earlier phase at each pairing with the outer planet until its final conjunction, with Moon a thin crescent, low in the west at dusk. You’ll see many beautiful events by just following the Moon’s wanderings at dusk and dawn in the three months leading up to the solar eclipse. 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.