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Sea Turtle Photo Identification Results

Hugh's Aquarium Views Number 31

Since 2008 when the Aquarium’s vet, Dr. Lance Adams, first introduced us to the sea turtles of the San Gabriel River, my wife Pam and I have been taking field notes and photos of these unexpected urban residents. The photos were used in a photo identification study project led by the National Oceanographic and Atmospheric Administration (NOAA). The results were presented this year as a scientific poster at the International Sea Turtle Symposium, a gathering of sea turtle scientists and researchers from around the world.

Here are some excerpts from the poster:


Hashimoto, S., JHaveri, P., Ryono, H., Ryono P., Lawson, D.


Although much has been learned about the green sea turtles (Chelonia mydas) and their use of this area, many fundamental questions remain about the population of green turtles in the San Gabriel River in Long Beach, California. Photo identification in sea turtles has recently been examined as an alternative study tool that minimizes the potential risks of disturbance or injury associated with other methods such as capture, as well as increased sample size compared to traditional tag-recapture due to ability of having data collection occur by numerous individuals at any time. Our results clearly illustrate the potential usefulness of photo ID data at this study site. Our next steps involve development of an organized photo collection program that can be incorporated into existing citizen science monitoring efforts, as well as additional participation from the public anytime photos can be collected. The project is expected to engage the public directly in the scientific process, which is likely to increase public awareness, environmental stewardship, and sea turtle conservation locally and beyond.

Citizen Science

This project aims to bridge the gap between science and the public, so as to allow for citizen science to be a more attainable goal. Through the efforts of volunteer photographers, Pam and Hugh Ryono from the Aquarium of the Pacific in Long Beach, CA, we were able to show that the gathering of data for biological monitoring can be conducted by any individual with quality photo equipment and patience to collect challenging photos. Once taken, these photos will eventually be able to be uploaded to a central database that simply asks for the photo file, date, time, left or right profile identification, location, and name of the photographer. By streamlining this data collection process, citizen science and photo capture for population quantification are an extremely manageable process.


  • 244 photos
  • Dates: August 2008 - October 2015
  • 76 individuals in total
  • 15 individual Left Profiles identified
  • 61 Right Profiles (turtles primarily traveling upriver?)
  • Range of Total sightings: 1-5 (different days)
    • 1 total sighting: 60 individuals (47 right profiles)
    • 2 total sightings: 8 individuals (7 right profiles)
    • 3 total sightings: 6 individuals (all right profiles)
    • 4 total sightings: 1 individual (all right profiles)
    • 5 total sightings: 1 individual (all right profiles)


  • Identified at least 61 turtles over the 7 year period near the mouth of San Gabriel River in Long Beach, CA
  • Resights on different days seem to be relatively rare. Could mean there is a high abundance of turtles regularly in the area or they may just be moving in and out often.
  • Presenting to the public may initiate active conservation efforts and long term monitoring
  • Citizen science will actively engage those that want to help local environmental preservation

Hopefully this study will be the catalyst to a wider future photo identification study of these urban sea turtle using Citizen Scientists.


There are two questions I usually get about my taking pictures of the sea turtles.

So why did I from the beginning start take pictures of the turtles?
Answer: It’s a holdover from my days many years ago as a flight test photographer. There is a B-2 Bomber on display at the Air Force Museum in Dayton Ohio. It’s actually a static, stress test vehicle that was used in the early days of the stealth bomber. I think I photographed every inch of that plane at one time or another. I once asked an engineer why I was taking picture of what to me was an insignificant part of the aircraft. His answer stuck with me. In research you never know what will become important so document everything. So with the sea turtles in the river I started photographing them just in case.

How do I seem to get more good shots of the turtles than most people?
Answer: Well it helps to be able to think like your subject. In the early days of the Aquarium of the Pacific one of my duties was to help take care of the four green sea turtles and two olive ridley sea turtles exhibited. I learned a lot about sea turtles from having to feed, wrangle and give medication to them. It helps me to anticipate their swimming and breathing patterns in the river.

Check out the video accompanying this blog below.