Kicking off the Field Trip
  • Safety: Upon arrival at the site, survey the area quickly to determine if conditions are “normal.” Should any unanticipated hazards be identified, an assessment must be made to determine if the field trip should continue as scheduled or be modified in any way.
  • Cultural protocol. Start your field trip by following cultural protocol, e.g., E Ho Mai (see field trip planning).
  • Introductions and science assistants. Have the class circle up (Figure 1). If you have science assistants, have them introduce themselves and, depending on the size of your class, your students can also introduce themselves as well. Have a brief conversation with your science assistants about your plan for the field trip and how they can help.
  • Low tide time. Remind everyone of the time of the low tide.
  • Field trip agenda. Go over the field trip agenda. Remind students of the safety rules.
  • Sense of place. If you have not already, share information about the site (see field trip planning), including its ahupua‘a, ‘lli, and watershed (and what these names mean and refer to); the history of the place; and current (local) human and environmental influences (e.g., urbanization of area, presence of cesspools) and threats (e.g., beach erosion, invasive species).
  • Species search and identification: If you have time, we highly recommend spending the first few minutes of your field trip looking at intertidal species in the area and having your students practice their identification skills. You may want to collect the dominant algae in the area and pass them around so everyone (including volunteers and chaperones) can see what they look like and practice identifying them using the OPIHI Identification Guide. This way you can help mitigate systematic identification errors and promote good identification methodology. For example, ask if students think a specimen is a red, brown, or green algae and then have them turn to this section of the guide. Then ask what other characteristics they notice and have them use this information to identify which of the pictured algae they are looking at. This way you can ensure everyone will be identifying the dominant organisms similarly. Use this opportunity to talk about the importance of everyone calling the same thing by the same name.

         Figure 1. Opening class circle at Diamond Head, O‘ahu

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Photo credit: Jessica Schaefer

Mindfulness Reminders

Respect for the Environment

  • Point out any site-specific potential hazards.
  • Watch the waves; be aware of your surroundings and bend your knees
  • If you allow your students to handle intertidal organisms (see this section below for more information), reminder them to handle the organisms gently, keep them wet, and return them to where they found them
  • Only pinch pick algae. Leave the holdfast.
  • If you turn over a rock, make sure you put it back the way that you found it.
  • Hold onto your trash (and pick up any trash you see).
  • Be aware of potentially hazardous marine organisms.
    • Don’t touch: Sponges, fireworms, hydroids, and cone snails
    • Don’t poke: Crabs or mantis shrimp, sea urchins and moray eels can cause injuries

These principles align with the Seven Principles of Leave No Trace—a framework for minimizing human impacts in outdoor space.

Mindfulness in data collection

  • Emphasize the importance of neat data collection—students must be able to read and interpret their data in order to enter it into the OPIHI database
  • Remind students to fill out the metadata information (e.g., transect number) at the top of their data sheets—this is important when entering information into the OPIHI database
  • Remind students of the importance of ethical and honest data collection.
Transect Line Placement

Following a standardized protocol, like the OPIHI citizen science protocol, allows more accurate comparisons to be made with the same site over time, and with other sites, than if protocols were more open-ended. If you make any deviations from this protocol, please make a note in the “comments” section of the database on the metadata page when you start a field trip and let us know in detail what you changed.

Lay Transect Lines

After making sure everyone has appropriate footwear, have your students divide into their groups (3–5 students per group) and lay their transect lines (Figure 2).

  • Transect lines should be laid perpendicular to shore.
  • Lay the lines as straight as possible and maintain equal spacing between groups (~2 m, although this distance will depend on the size of your site and number of groups).
  • The “0” mark should be in the water (low intertidal zone). The transect reel should be on land (high intertidal zone).
  • Use the high water/surf line (also called the run-up limit or upper limit of the swash zone) as the transect end point. To determine this end point look for evidence of water (e.g., pools of water or wet sand) or the end of the organisms that live in the high intertidal (e.g., the limit of the high intertidal snails).
  • You can weigh the transect line down with rocks or weights to prevent it from moving. However, if it does move a little that is OK. It is mostly important that the same area of the intertidal is not surveyed by more than one group (pseudoreplication).

Length of Transect Line

The total length of transect laid out will depend on the length (distance between the water lines at high and low tide) and morphology of the intertidal site. The Hawai‘i State Department of Education does not allow public school students to get wet past their knees. Thus, your transects cannot extend into an area that is too deep. You are responsible for knowing how far the transect lines should extend into the water based on prior visits to the site. All the transect lines should be roughly the same length, although some variation is OK based on the contours of the intertidal site.

Transect Numbering

When you are facing towards the ocean, transect “1” is on your far left.

   Figure 2. Laying transect lines at Diamond Head, O‘ahu

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Photo credit: Jessica Schaefer                        Photo credit: Kanesa Duncan Seraphin

Model Transect and Quadrat Data Collection

Even if your students have practiced the protocol multiple times in the classroom, bring your class together and model the collection of transect and quadrat data.

Fill out Metadata

The first thing students should do is fill out the top portion of their data sheets. Filling out metadata is an important but often overlooked step. Transect line number information is especially important as students will need it when entering data into the OPIHI database.

Transect Point-Intercept

Transect point-intercept data can be any standard distance (e.g., every 1 or 2 m). The interval will depend on the width of your study site.

  • If not already on their data sheets, remind students of the point-intercept distance for data collection.
  • Model the collection of a couple of point-intercept data points with your students.
  • Record which single species (e.g., Turbinaria ornata) or substrate (e.g., sand) you find directly underneath the point. Record only the organism on the top.
  • Use a skewer or pencil to help determine what is directly under a transect point.
  • Although students might work from either low-to-high or high-to-low in the intertidal depending on the tide, on the transect data sheet “Reference Point Number 1” should be the transect point which is furthest from shore.

In all OPIHI methods (both transect and quadrat data collection), record the organism on the surface. For example, if under one point is a snail on top of an urchin on top of algae on top of rock, record the species of the snail. Do not count things that are transient in the intertidal, like trash, leaves, or water.

Quadrat Point-Intercept

Each OPIHI field trip should plan to sample at least 25 quadrats in the intertidal. See field trip planning to determine how many quadrats each transect group needs to sample (Figure 3). Gathering data from more than the minimum 25 quadrats is preferred in case some of the data is not representative of the overall area (e.g., species along one transect are mid-identified). Each additional quadrat you sample will likely make the overall data more comprehensive and representative of the study site at the time of sampling and more useful for later ecological analyses. However, it is also important not to rush the sampling protocol either—a large number of quadrats is not useful unless the data is “good” (e.g., the species are accurately identified). OPIHI field trips are about balancing this need for accurate data collection with the number of quadrats and the time available for data collection (generally about two hours around low tide).

If not already on their data sheets, remind students of the intervals along the transect (e.g., every meter) they will be collecting quadrat data, and how many total quadrats per transect they should end up with. Also tell them at which meter they should start collecting data (e.g., 0 m or 1 m). Model data collection for one quadrat.

  • Have students decide as a class how to place the quadrat at the transect point (e.g., put the bottom left corner of the quadrat on the 1 m point of the transect tape). All groups should place their quadrats in the same manner.
  • Have students identify the dominant species in the quadrat (without looking at the point intercepts). Work with them to identify things they do not know using the OPIHI Identification Guide (Figure 4). If a species is missing on their data sheets, have them write it in.
  • Model how to systematically take data (point by point, one row at a time) by calling out what is under each point. For example “Padina, Padina, Padina, Sargassum, Holothuria atra” might be one row of five points. Model how to “pinch pick” a small piece of algae from under a transect point to examine it more closely. Go slowly.
  • Check to make sure the student recorder is “ticking” each of these species on the data sheet as you go and that the “ticks” are in the correct boxes (see sample OPIHI data sheets for a visualization of this step).
  • Pick a small sample of each new species of algae recorded (e.g., you would only collect a piece of Padina once) to put in a plastic bag with some seawater (or a pillbox) labeled with the transect number. This algae will be used to create a class algae voucher. The purpose of an algae voucher is to create a record of the species you observed on your field trip and so we can spot check your accuracy.
  • Have students complete the rest of the model quadrat. Check their methodology, identifications, and transcriptions. Ask if anyone has any questions.
  • Before moving the quadrat, have the students add up the points to make sure there are 25 (or close to 25!) and that they did not skip any rows.

Figure 3. Collecting quadrat data at (A) Waipuilani Beach, Maui; (B) Waipouli Beach, Kauai; (C) Maili Beach, O‘ahu; and (D) Diamond Head, O‘ahu

Photo credit: Kanesa Duncan Seraphin (A, B, D), Jessica Schaefer (C)

Identification Reminders

  • Emphasize to students that not everything they will see will be on the OPIHI Identification Guide. They may have to consult science assistants, their teacher, or identification books. Unknown algae species should be collected in their own labeled bags, separate from algae for the voucher, to be identified in the classroom. Students should transcribe each unknown using the same label throughout the field trip (e.g., “Unknown 1”). When identified, students will need to change this label on their raw data sheets to the correct species.
  • Remind students that additional species can be written in the blank spaces of their data sheet.
  • See our species identification page for identification guidelines.

Remind students that the intertidal is more like Waikīkī than Moloka‘i. It is valuable real estate! Most sites in the lower and mid-intertidal will not have a lot of bare rock. But, as things are small, they have to look closely to see the diversity.

Figure 4. Using the OPIHI Identification guide at Diamond Head, O‘ahu

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Photo credit: Jessica Schaefer

Student Data Collection

Have students work along their transects collecting and transcribing their transect and quadrat data.

  • Students should collect all transect data first to avoid flipping their data sheets. Collecting transect data first also allows students to become familiar with the dominant species at the site before starting the more labor-intensive quadrat sampling procedure.
  • For quadrat data collection, have students work their way into or out of the water depending on the tide (e.g., if the tide is coming in, your class should start at the deepest portion of the transect).
  • Remind your students of their data collection group roles and to cycle through roles over the course of the field trip (so that everyone has an equal opportunity to perform each role).

Field Assessment

Spot-check student data sheets to ensure students are adding up their point-count numbers (each quadrat should have 25 data points, totaled at the bottom of each data column). This is an important data verification step in the field that students should be performing on their own before moving onto the next quadrat.

Be prepared for student groups to end at different times. Check the data sheets of groups that end suspiciously quickly—you may want to direct them to replicate their data collection. If you allow students to explore the intertidal after collecting their OPIHI data, establish and indicate the boundaries of their “exploration area.”

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Teacher Task—Field Trip Metadata

As a teacher, you need to fill out the class metadata sheet. Metadata is important for sharing information with others, finding correlations, and looking at trends over time. OPIHI metadata includes information about:

  • Wind and waves. Waves have an effect on how much water moves in and out of the intertidal, which can impact temperature and nutrients. Waves can also have physical impacts on the movement of sand and organisms. Wind can affect evaporation rates and water clarity. Observing both wind and the waves can help to describe and characterize the general environmental conditions at your site while you are sampling.
  • Rain events. Rain events can influence the species found at a site as rain lowers the surface salinity and can affect the water temperature. To determine how much it has rained recently, use the Weather & Hazards Data Viewer of NOAA’s National Weather Service.
    • Zoom in to the island of interest (e.g., so all of Oahu is displayed in the window).
    • Click on the “Overlays” in the drop-down menu and choose the “Observations” tab.
    • For “Display” choose “Precipitation,” for “Duration” choose “72 Hour,” for “Provider” choose “All Networks,” and for “Density” make sure you choose the “All” radio button.
    • Choose the station closest to the site and input the value.

These are directions for getting the last 3 days of rainfall information. If you need more historical information, adjust the time to “historical” and the start and end dates accordingly.

  • Environmental stress. Record any evidence of environmental stress that you witnessed. You should only record evidence of environmental stress if it appears to be substantial. For example, if you saw one dead urchin, that is not evidence of environmental stress. However, if you saw a hundred dead urchins, that is evidence of some abnormality in the ecosystem.
  • Human impact. Humans can trample species in the intertidal. Humans also collect organisms in the intertidal. How urbanized the nearby area is will affect runoff and may affect traffic to an area.
  • Sampling information. Enter the number of transect lines and the length of the longest transect (in meters). The “distance between transect points” box on the metadata sheet refers to how often you had students collect transect point-intercept data (e.g., every half meter, meter, or every two meters). For the quadrat point-intercept method, record the maximum number of quadrats on a transect (called “# of quadrats per transect” on the metadata sheet). This information is important as it will be needed when you set up the OPIHI database for data entry for your field trip.

With the exception of rain, you should have the metadata sheet completed by the end of the field trip. You will need to transfer this information into our database when you start a field trip.

Remember to take a lot of pictures! If you have great ones (and student consent/permission!), please contact us to share them. We love seeing you and your students in the intertidal!

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Water Quality

The OPIHI citizen science monitoring protocol focuses on intertidal organisms (biology). The biology of an area is reflective of the area’s physical and chemical environment. Integrating water quality monitoring into your field experience connects intertidal organisms to the rest of the ahupua‘a—the intertidal is affected by what is happening both upstream on land and in the ocean (Figure 5).

Because OPIHI does not standardize water sample collection procedures, we do not collect your water quality. However, this allows your students to be creative in their research questions, research design, and data collection. Common water quality instruments are listed in supplies.

Schedule water quality testing either before or after the biological survey, depending on the tide and when you have more time on your field trip. Remember that because the sensitivity of most classroom instruments is low, and because the differences in measured water properties are small, we expect most water quality variables to be similar throughout the intertidal, especially if the tide is up and/or there are no tidepools at your site.

Figure 5. Determining the dissolved oxygen concentration of the water at Diamond Head, O‘ahu

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Photo credit: Kanesa Duncan Seraphin


Handling Intertidal Organisms—Invertebrates

Many intertidal invertebrate organisms are safe to handle (Figure 6). They can be held in your hand for a limited period of time (as they are intertidal organisms, they are used to being exposed to the air). However, it is very important that the organisms stay wet and that you handle them gently. This entails holding organisms in the palm of your hand and not pinching, squeezing, or dangling them. Remind your students to treat intertidal organisms with respect. If you do not think your students can treat the organisms with respect, do not allow your students to handle them. Reiterate the hazardous organisms students should not handle prior to the field trip (e.g., sponges, eels, cone snails, fireworms, crabs, urchins, mantis shrimp, hydroids).

If you have containers to temporarily place organisms in, keep the organisms from overheating and the water from becoming anoxic by periodically having your students exchange the warmer container water for fresh ocean water and either keeping the buckets in the shade or covering them so they remain shaded. When placing organisms back in the water, try to return them to their original location. Other organisms depend on the shade and protection given by rocks and should be returned to them if removed, for example brittle stars will appreciate being put back near, or under, a rock.

Please do not collect invertebrates to bring back to your classroom.

Figure 6. Tripneustes gratilla (collector urchin) and Gracilaria salicornia (gorilla ogo)

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Photo credit: Kanesa Duncan Seraphin

Wrapping Up the Field Trip
  • Take a group picture!
  • Collect algae for presses. If you have time in the field, and class time later in the week, bag up some algae to make algae presses. These presses would be for your students, and are separate from the press you will create as an algae voucher.
  • Collect some seawater. If you are not making your algae voucher (or algae presses) immediately after the field trip, the algae will need to be placed in containers of seawater in your classroom. See species identification for how to care for picked algae.
  • Look back at the site. Have students look back at their intertidal site and see the effects of their activity on the area, for example: the sand will be compacted, rocks will have been moved, algae will have been compressed. Use this opportunity to talk about human environmental impacts and tell your students to make this experience, and their inadvertent impacts to the intertidal, matter.
  • Clean up and pack up!