Summer Project: Training Tools for Fish Surveys

Summer Project: Training Tools for Fish Surveys


As a data analyst major and a psychology minor, finding a way to incorporate my field of study into marine biology was definitely a challenge. I was too focused on setting aside my educational background and trying to learn a new subject that I had difficulties settling on a project. Then I thought, “Why not do a little bit of both?”

In order for the Natural Resources Management to make sound decisions, they need accurate data, which requires accurate data collectors. This summer, the War in the Pacific National Historical Park (WAPA) Marine Team was tasked with putting together a protocol for conducting reef fish surveys. Because we were going to be the ones to start off this project, we needed to be trained in two areas: fish species identification and fish sizing. This created the question underlying my project: How can we develop effective training modules that will give individuals like ourselves the tools we need to conduct these surveys?

Part 1: Species ID

Gathering data on fish species will help the park take inventory and understand the biodiversity of the ecosystem. For this, we used Quizlet as the training tool for several reasons: it’s easily accessible, it’s open to the public, and it offers different ways to study based on your preference. We compiled a list of the most common fish species in Guam’s reefs, and more specifically, in the park’s reefs, and we created three study sets that included the scientific names, ID Codes, and photos of each fish. Our study sets, which includes 293 species of fish, can be found at this link:

Guam Reef Fish – Training 1 study set with different methods of studying on the left and the flash cards on the right

WAPA folder with the Guam Reef Fish Training study sets that are publicly accessible

Example of the “Spell” studying method that shows the photo and common name of the fish and requires the user to write the scientific name

Part 2: Fish Sizing

Not only do we need to be able to identify the fish, but we must be able to estimate their sizes to account for biomass. To train for this, we needed fish models that could be put into the water that could help us practice sizing. It took a good amount of trial and error, but we finally developed some robust prototypes that did what we needed them to do. We made 33 wooden models varying in size and shaped after different types of fish that were tied to stainless steel nuts and chain links using nylon string. The weight of the metal working with the buoyancy of the wood allowed the fish models to be suspended in the water as if they were actual fish!

Fish Models placed in the water in preparation for sizing practice

Wooden fish model tied to stainless steel bolts using nylon string to keep it suspended in the water

To test the models, we went through the following process:

  1. Place fish models in the water, in a random order, scattered within about two meters along a straight line.
  2. Have trainees number their datasheets from 1 to 34 (number of fish models) and write down their size estimates of the models next to their corresponding numbers.
  3. After one round of practice, have trainees go over their results by comparing their estimates with the actual sizes.
  4. Have trainees measure their hands and/or fingers for size references.
  5. Rearrange the placement of the models in a random order.
  6. Repeat Steps 2 and 3.
  7. See if there was an increase in accuracy.

Xavier Quinata practicing fish sizing with his underwater datasheet

WAPA marine team writing down size estimates during sizing practice


After just one round of practice and introducing personal size references, we saw an increase in accuracy, reducing the margin of error to about 1-2 cm. My plan is to adjust this process by putting time constraints, iterating this process over multiple days, and using two different sets of models for the two practice rounds to prevent memorization. There were minimal issues with the models themselves, such as loose knots and insufficient weight, but they have been adjusted accordingly.

Some questions I wish to explore further include:

  • Is it more difficult to accurately size larger fish than smaller fish?
  • Does the height of the fish affect the ability to size the length?
  • Does experience with fish and marine biology affect an individual’s sizing accuracy?

I may not be able to uncover answers to all these questions, but it would be useful information to take into account for the park for future trainings. Although there is still much to work on, we have developed a couple useful training tools for fish surveying that can be used by future interns or employees.

  • Mike Gawel
    Posted at 20:33h, 24 July

    Nice work Xavier. We did similar training at WAPA over ten years ago for the NPS I&M reef monitoring. And back in 1976 I did one-time transacts of fish species and sizes in the Agat reefs that now are in the Agat Unit reefs.

    • Xavier Quinata
      Posted at 21:03h, 24 July

      That’s awesome! I’d love to hear about what you guys did for your training to see if there’s anything else we can add to ours.

  • Mike Gawel
    Posted at 17:25h, 02 August

    I hope I can meet with Tim and Ashton and you and others soon.
    Please keep in touch at: