How Everyday Citizens Are Unlocking the Secret Lives of Green Sea Turtles
In the gentle waves of La Jolla Shores, a snorkeler's camera clicks, capturing a moment that science alone could not
Beneath the surface of Southern California's coastal waters, a quiet revolution in marine science is underway. For years, studying elusive sea turtles was the domain of a few dedicated scientists with limited resources. Today, a transformative partnership is revealing astonishing new insights about these ancient mariners, powered not by research grants alone, but by the curiosity and cameras of everyday citizens.
Why Turtles Need Southern California—and Our Help
The East Pacific green turtle, known to scientists as Chelonia mydas, has made a remarkable comeback over the past two decades. Thanks to comprehensive protections at nesting beaches and foraging areas, their numbers have surged. From a low of roughly 230 nesting females per season in the early 1980s at Colola Beach, Mexico—the primary nesting beach for this population—the numbers have skyrocketed to more than 7,500 females per year from 2014 to 2017 1 .
Southern California represents the northernmost reach of their range, where turtles find critical foraging habitats in bays, lagoons, and estuaries . These areas provide rich feeding grounds with abundant seagrass and algae, the preferred diet of these marine reptiles.
Did You Know?
Unlike other sea turtles, greens are primarily herbivores as adults, their body fat tinted green by the plants they consume—the very characteristic that gives them their name 4 .
Modern Threats
- Boat strikes in busy waterways
- Entanglement in fishing gear
- Ingestion of plastic debris
- Loss of vital eelgrass habitats
Despite their recovery, green turtles face modern threats: boat strikes in increasingly busy waterways, entanglement in fishing gear, ingestion of plastic debris, and the loss of vital eelgrass habitats to coastal development and pollution 4 . Understanding how turtles use Southern California's waters is crucial for their continued protection.
The Accidental Laboratory: La Jolla Shores
In La Jolla Shores, a semi-protected cove near San Diego, a unique situation presented scientists with an unprecedented opportunity. Since around 2014, green turtles began appearing regularly in this area popular with kayakers, snorkelers, and divers 1 3 .
The turtles here have become habituated to humans, often displaying curiosity rather than fear when approached 1 . This behavioral adaptation created perfect conditions for a novel research approach. Traditional capture-recapture methods were ill-suited for this frequently visited public area, requiring an innovative solution that would both protect the turtles and satisfy public relations sensitivities 1 .
La Jolla Shores, where green turtles have become habituated to human presence.
The Experiment: Cracking the Case with Citizen Photography
Between April 2016 and June 2019, researchers from Scripps Institution of Oceanography and NOAA embarked on an ambitious project to study La Jolla's turtle aggregation through citizen-sourced photography 1 .
Step-by-Step Methodology:
Engagement
The team collaborated with local divers and snorkelers, encouraging them to submit photographs of green turtles encountered during their underwater excursions 1 .
Data Collection
Over three years, they amassed 309 usable photographs of local green turtles, each image containing valuable data about the individual turtle, its behavior, and its immediate environment 1 .
Identification
The images were processed using Hotspotter, a sophisticated pattern recognition software that analyzes the unique arrangement of scales on a turtle's face to identify individuals, much like facial recognition technology identifies humans 1 .
Behavioral Analysis
Researchers documented turtle behavior visible in each photograph—categorizing activities as active swimming, foraging, or resting—and recorded environmental factors like visible algae coverage on the carapace and habitat type 1 .
Remarkable Findings: The Picture Comes into Focus
The results, published in the journal Frontiers in Marine Science, revealed insights that would have been impossible through traditional methods alone 1 .
The software identified seven distinct individual turtles from the 309 photographs, five of which were consistently photographed throughout the study period 1 .
By analyzing the timing of sequential photographs for each identified turtle, researchers calculated a mean minimum residency duration of 424 days, demonstrating that La Jolla Shores supports a truly resident population, not just occasional visitors 1 .
Minimum Residency Duration
| Turtle Identifier | Minimum Residency (days) |
|---|---|
| Turtle A | 555 |
| Turtle B | 482 |
| Turtle C | 425 |
| Turtle D | 390 |
| Turtle E | 388 |
| Turtle F | 131 |
| Turtle G | Not determined |
| Mean Residency | 424 |
Green Turtle Behavior
| Behavior Category | Percentage of Photographs | Interpretation |
|---|---|---|
| Active | 82.8% | Normal swimming and movement |
| Foraging | 14.9% | Feeding on algae and other food sources |
| Resting | 2.3% | Stationary on bottom or mid-water |
Cold-Water Foraging Discovery
Perhaps most remarkably, the study documented green turtles foraging in water temperatures as low as 15.8°C (60.4°F), the lowest temperature at which foraging has ever been documented for this species 1 .
Beyond La Jolla: A Regional Movement
The success at La Jolla Shores is not an isolated case. Across Southern California, similar community-driven initiatives are generating valuable data:
Since 2008, the Aquarium of the Pacific has run a Green Sea Turtle Monitoring Project in this unlikely urban habitat, which now represents the northernmost known resident population of green turtles 8 .
Volunteers conduct monthly surveys, recording turtle sightings, sizes, and behaviors. Their data has documented a weak but encouraging increasing population trend .
Building on the La Jolla approach, volunteers in the San Gabriel River are now creating a database of high-quality turtle photographs for the Internet of Turtles platform, which uses artificial intelligence to match turtle sightings across Southern California 8 .
The value of citizen science extends beyond turtles. The REEF Volunteer Fish Survey Project has engaged recreational divers in marine life monitoring for decades, with data now used to track trends in Caribbean groupers and sharks 2 .
Key Citizen Science Programs
| Program Location | Lead Organization | Primary Methods | Key Contributions |
|---|---|---|---|
| La Jolla Shores | Scripps/NOAA | Underwater photography, pattern recognition | Documented resident population, minimum residency, cold-water foraging |
| San Gabriel River | Aquarium of the Pacific | River bank surveys, behavioral observations | Northernmost population record, long-term trend data |
| Regional Waters | REEF | Volunteer fish surveys, opportunistic sightings | Regional distribution patterns over decades |
The Scientist's Toolkit: How You Can Contribute to Sea Turtle Science
Modern marine biology relies on both advanced technology and simple observations. Here are the key tools and methods powering this research:
Underwater Cameras
From simple GoPros to sophisticated camera systems, these devices provide the primary data source—visual evidence of turtles in their habitat 1 .
Citizen Science Platforms
Websites like iNaturalist and organization-specific platforms allow volunteers to submit sightings and photographs, which researchers can verify as "research-grade" observations 9 .
Laser-Mounted Cameras
In REEF's SMILE Project, divers use cameras equipped with laser scales to document fish lengths, providing crucial size data for population assessments 2 .
Observation Protocols
Standardized data sheets used by volunteers record essential information like location, time, turtle size, behavior, and environmental conditions 8 .
A Symbiotic Relationship: The Ripple Effects of Citizen Science
The benefits of these citizen science initiatives extend far beyond data collection. When recreational divers, kayakers, and beachgoers transform into observers, they become invested stewards of marine ecosystems 5 . This engagement builds crucial public support for conservation policies and marine protected areas 5 .
California's network of 124 Marine Protected Areas has explicitly incorporated citizen science into its monitoring strategy, recognizing that public participation contributes not only data but also strengthens the connection between communities and their coastal environments 5 . As one study noted, these collaborations yield "mutual benefits for both the growing use and utility of citizen science and its role in marine conservation" 5 .
The Future of Turtle Conservation
The story of citizen science and green sea turtles in Southern California represents a powerful new model for conservation biology. It demonstrates that rigorous scientific insights can emerge from the coordinated efforts of passionate citizens armed with increasingly accessible technology.
As one research team concluded, "This study highlights the value of citizen-based science in areas where traditional research techniques are ill-suited" 1 . The habituation of turtles to humans in La Jolla—once potentially viewed as a problem—has become the key to understanding their lives in unprecedented detail.
The recovery of the East Pacific green turtle remains a work in progress, but through the lenses of citizen scientists, we are gaining the knowledge necessary to ensure these ancient mariners continue to grace Southern California's waters for generations to come.