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OPIHI Supplies

Before Starting OPIHI, you will need to obtain the following supplies. We suggest that you divide up the number of students in your largest class (e.g. 28) by 4. This is the number of transects, quadrats, photoquadrats, Hawaii invertebrate books, Hawaii algae books, sets of ID cards, and clipboards you will need, assuming your class works in groups of four (in our example this would be seven). We recommend one or two Hawaii fish books and one or two packages of waterproof paper per teacher. After a field trip it is important to wash off all of your equipment in fresh water to prevent damage from salt water.

Hawaii Marine Algae Book:

Hawaiian Reef Plants, by Huisman, Abbott, and Smith
- Available through UH Seagrant and at most Hawaii bookstores.
- Only student user-friendly Hawaii algae book. Please remember it is not inclusive (that would make it MUCH bigger!) and covers algae found at many different depths, not just the intertidal.

Hawaii Invertebrate Book:

Hawaii's Sea Creatures: A guide to Hawaii's Marine Invertebrates, by John Hoover, Mutual Publishing.
- Available at most Hawaii bookstores and online at (e.g.) Amazon.
- This is the best Hawaii invertebrate book. Again please remember it is not inclusive and covers invertebrates found at many different depths. Even scientists haven't fully described many groups such as sponges and xanthid crabs!

Hawaii Fish Book:

Hawaii's Fishes: A guide for snorkelers, divers and aquarists, by John Hoover, Mutual Publishing .
- Available at most Hawaii bookstores and online at (e.g.) Amazon.

Shore Fishes of Hawaii, by Jack Randall, University of Hawaii Press.
- Out of print, but still available at some bookstores, including the UH bookstore, and online at (e.g.) Amazon.

**Both of these fish books cover a selective number of fish species from a wide variety of depths and locations. Thus many of the intertidal gobies and blennies, the two most common intertidal fish, are not included in either book. However, both books have pictures of other intertidal fish such as eels and reef fish, and have pictures of gobies and blennies so students can learn to identify if a fish belongs to either of these broad groups.


A transect line is any line, marked at regular intervals, that is easy to use in the field. Organisms can be surveyed along a transect to determine their abundance and distribution.

We order our transects from Forestry Suppliers (www.forestry-suppliers.com Or ph: 800-647-5368). Tape are found under "Surveying, Engineering, and Mapping Equipment" and then the sub-category "Tapes, Fiberglass". We recommend Keson open reel fiberglass tapes. Choose the length of your tape based on the length of the intertidal site you will study. We've found the 50m long transects are sufficient for all Hawaii intertidal site we have surveyed thus far. Your transect tape should have metric measurements. You can choose between tapes that have both metric and English measurements or just metric measurements.


A quadrat is a framed area that can be divided into a grid of squares used to determine organism abundance. There are many different sizes of quadrats used for many different types of sampling. It is important that you use the same size quadrat as the rest of the schools involved in OPIHI so results can be compared throughout the islands. We use a 12" X 12" square quadrat strung with fishing leader to create 25 evenly spaced points and 36 squares within the quadrat. You will have to construct the quadrats yourself out of 1/2" PVC drilled with 5 evenly spaced holes and fishing line leader.

See "How to Make an OPIHI Quadrat".

Identification (ID) Cards:

OPIHI ID cards have common intertidal algae and invertebrates that you are likely to encounter on your field trips. You will most likely also encounter organisms not on these ID cards, which you can look up in the books. Print out the ID cards and laminate them with thick plastic (available at Kinko's). This is to insure they will remain waterproof for many years. The following Identification cards were developed for Oahu intertidal sites. We has found they word well for many of the sites on other islands as well. However, if your class is monitoring a particularly unique site, you many want to develop your own site-specific identification cards.

Algae Identification Cards
Invertebrate Identification Cards 1
Invertebrate Identification Cards 2

It is convenient in the field if holes are drilled into the ID cards and placed on a ring. In order to do this without compromising the waterproof quality of the cards, you can only drill a hole through the laminate plastic on the edges of the finished ID card, not where the plastic sandwiches the piece of paper. Thick laminate sheets are designed to fit snugly around an 8 ½ x 11" piece of paper. In order to drill a hole, you have to increase the margin of plastic around the paper. To do this, cut down the white margins from the 11" sides of the ID cards. When laminating, ask that the cards be places as far as possible into a corner of the laminate sheet, which will leave a space wide enough to drill into the plastic on the opposite side. The cards can be attached with binder rings, but these will rust with repeated exposure to the water unless thoroughly washed with fresh water after each use and dried. Plastic binder ties may also be effective.


There are seven intertidal photoquadrats, life-sized photographs sized to fit OPIHI sized quadrats, used to practice quadrat techniques in class. They are on 14 pages, two for each photoquad. Print out all 14 pages and then line up two pages as closely as possible before laminating to make each photoquad. These are described in more detailed under "Understanding Sampling - Measuring Abundance" in "Classroom Preparation".

Waterproof Paper:

We recommend Xerox 8.5"x11" polyester paper 3R12363. You can order this on the Xerox website (www.xerox.com). Order one to two boxes depending on the number of field trips you are planning to take.

Clipboards, Large Rubber Bands, and Pencils:

Most classes already have clipboards. You will need one for every four students in the field. If you are ordering clipboards specifically for OPIHI, we recommend the clipboard have plastic components to withstand water immersion.

Large rubber bands are used to secure the end of the data sheet to the clipboard and keep it from blowing around.

Pencils are necessary to write on waterproof paper. Any pencil will do, although some marine ecologists have found that writing with pencils made entirely of graphite (with no wood) or with interchangeable tips (where you replace a tip by pulling it off and placing it into the top of the pencil to get a fresh sharpened point) are useful as you'll always have a sharp pencil. To prevent pencils from getting lost, we recommend attaching them to the clipboards.

Lead Weights (or similar):

We use lead dive weights, one per field group, to weigh down the ends of our transect lines and keep them from moving in the water. They are inexpensive and found at most dive shops and some discount stores throughout Hawaii. An alternative is to collect rocks (approximately 3-4 lbs) to use as weights. Many intertidal sites will not have appropriately sized rocks, and you will have to bring your own.

First Aid Kit:

The first aid kit should contain standard first aid materials as well as:
" Vinegar: neutralizes many marine toxins, such as those found in jellyfish and certain reef fish (meat tenderizer does the same thing, but is not as well proven)
" Sunscreen: to pass around at the beginning of the field trip
" Water: In case of dehydration

Cell Phone:

To be used in case of emergency. Make sure your intertidal site has reception from your cell phone company provider before the first field trip.

Water Shoes:

Every student who participates in OPIHI field trips must wear closed-toed shoes. Rocks in the intertidal can be slippery and sharp, thus it is necessary to protect our toes and wear shoes with good traction that you don't mind getting wet. In Hawaii, some students might not have any as we wear slippers so often, or might only have one good pair of sneakers that they, or their parents, may not want going into salt water. These students may not be able to purchase shoes, and so some teachers have found it useful to buy a few water shoes in a variety of sizes for the class to use. Water shoes, neoprene slip-ons with rubber soles, are sold at many sporting and discount stores throughout Hawaii and can be purchased for under $10/pair.

* = recommended

*Buckets or Large Plastic Container

Buckets and/or a large plastic container is useful to carrying all the supplies from the bus to the intertidal site.

*Look boxes or Tupperware containers:

Look boxes are clear boxes without a top that are used to see more clearly through ripples and sunlight reflection on the water to the bottom of the intertidal. The boxes are pushed slightly into the water while keeping the inside dry. Rectangular boxes that are tall are easier to use as it is easier to keep water out of them. Handles are also a nice touch. Look boxes can double as temporary field tanks and a place to keep interesting organisms for a class show-and-tell at the end of a monitoring field trip. Boxes can be constructed of plexiglass sealed with silicone.

Tupperware and similar clear plastic containers can serve as effective look boxes. Look for containers with flat bottoms that are deep. Plastic containers with lids can double as holding tanks to transport organisms from the intertidal to a classroom aquaria.


Not only to take pictures of your students for posterity, but also to take pictures of organisms at the site that can be used in assessment projects, to remember and identify difficult organisms back in the classroom, and to show next-year's class!

Plastic Bags:

To store the books in on field trips to prevent accidental water splashes and sand from getting on the books.


To try and capture fish. Intertidal fish are very cryptic and blend into their surrounding very well. They are also very fast! While nets are fun to use to try and capture fish, many other organisms can be looked at more closely and do not escape as quickly.


As long as your students are careful when they touch organisms, and are taught which organism to be wary of, it is not necessary to provide them with gloves. However, some teachers have found it useful to provide students with the option of wearing gloves, especially when touching organisms like sponges, which contain spicules, which can get under your skin and cause discomfort. Rubberized gloves make turning over rocks in cobble areas more enjoyable.


If you are going to a cobble intertidal site (see sampling lessons) and are planning to measure the rocks you will flip over, you will need one ruler per field group.

OPIHI: Our Project in Hawaii's Interdental - Contact: philippo@hawaii.edu