Choosing a site

If possible, go to a previous OPIHI site. This contributes data to the long-term monitoring scientific goals of OPIHI and allows for an examination of intertidal changes over time.


Sense of Place

  • Where is your site located: moku, ahupua‘a, ‘lli, and watershed?
  • Place name(s)—what do they mean?
  • History, e.g. mo‘olelo (stories), events
  • What current human and environmental threats do the watershed and associated intertidal system face? (e.g., Is the site near a developed/developing area? Is the site near sources of fertilizer?)?

You can also have your students research this information, and/or share this information in class while preparing for the trip or on site during the field trip.

Opihi researchers at the fishpond

Choosing a Date & Time

  • Field trips need to be planned around low tides.
  • In Hawai‘i the difference between high and low tides is about 1 m (3 feet).
  • We do not recommend scheduling field trips on low tides higher than 0.0.
  • To determine the best time to go into the intertidal, consult a tide table. A good website is NOAA’s Tides and Currents (click on the station closest to your intertidal site).
  • Most websites measure the tide in feet. Assume the tide height and time at your field site will be similar to the closest given location on the website, or average the values for two locations on either side of your site.
  • Schedule your field trip to straddle the low tide. Within an hour after low tide, a site can be covered by water. For instance, if the low tide is at 10 am, you would ideally have a field trip from approximately 8:30 to 11 am (arriving early to get situated and timed to collect data while the water level is lowest).
low tide example image
low tide example image

Length & Number of Trips

  • In general, total amount of time at the intertidal site is 2.5-3 hours. Two hours for surveying the intertidal, plus time to get situated in the beginning and debrief at the end.
  • Time of travel to and from a site should also be considered.
  • If at all possible, take your students on two trips. On the first trip students can become familiar with the environment, the sampling design and methodology, and be exposed to the species in the area. On the second trip students will be in a position to take more accurate data.
    • If you are unable to go on multiple field trips, plan to spend more time in the classroom practicing sampling techniques and bring in organisms to get your students familiar with them before going into the field.
Students practicing in classroom

School logistics

Work with your school to complete field trip preparations. Exact procedures will vary by school. These are some of the common things to consider:

  • Permission forms
  • Medical information forms
  • Emergency contacts
  • While OPIHI is a water-related activity, students are not swimming (they should not get wet past their knees). To ensure compliance, make sure to check the most recent Hawai‘i Department of Education guidelines for water-related activities.

Students & Assistants

  • We recommend groups of 30 or less or both classroom management and site conservation considerations.
  • Check the DOE chaperone requirements for your grade level if required. Chaperones and other science assistants should be accounted for in tallies of participants.
  • Recruit as many science assistants as possible—ideally one for every transect group.
    • Science assistants can be scientists, graduate students, undergraduate students, and interested members of the public—it is most important that they are science-enthusiastic (Figure 3)!
Students and teachers collecting data


Schedule transportation to the site. This is usually by school bus. Bus scheduling should be done as early as possible. If your school will not pay for a bus, you can:

  • Split up the cost of the bus among the students.
  • Ask your school parent teacher association to sponsor the trip.
  • You may be able to arrange travel to your site through your local public transportation (e.g., The Bus on O‘ahu). Your school and site must be on their regular route. Call for more information.
  • Arrange for parents or guardians to carpool students to a site.
  • Apply for funding (e.g., Kōkua Hawaiʻi Foundation Project Grants, SOEST TGIF Mini-Grants)

Site planning – Samping Regime

If possible, prior to your field trip if determine:

  • number of transects,
  • interval along the transects at which you will take transect point-intercept data
  • number of quadrats along each transect
  • spacing of quadrats along the transects
  • Fill out this information for your students on their datasheets before printing (see Field Protocol for more information on the OPIHI sampling protocol).
Photo on UH Hilo story