The endangered giant sea bass (Stereolepis gigas), also known as the “king of the kelp forest,” is showing hopeful signs of population recovery off the Southern California coast—thanks to an innovative community science project.
🐟 What Is the Giant Sea Bass?
The giant sea bass is one of the largest predatory fish in California’s coastal waters. These massive marine creatures can grow over 7 feet in length, weigh more than 550 pounds, and live up to 76 years. They play a vital ecological role by keeping populations of smaller fish in balance, maintaining the health of kelp forests and rocky reef ecosystems.
Sadly, this slow-growing species was nearly fished to extinction by the early 1980s. Historical records show a 95% decline in commercial catches from 1932 to 1980 in California and Mexico. The species was officially listed as critically endangered by the IUCN in 1996.
📷 Citizen Science Sheds Light on a Hidden Population
A new study led by UC Santa Barbara’s Benioff Ocean Science Laboratory offers the first-ever direct estimate of giant sea bass numbers in Southern California. Published in the journal Marine Ecology Progress Series, the research utilized over 1,600 photographs contributed by scuba divers and fishers through the Spotting Giant Sea Bass Project, a community science initiative.
Between 2015 and 2022, the researchers identified more than 1,200 adult giant sea bass using unique spot patterns on the fish, similar to a fingerprint. These distinctive markings stay consistent throughout the fish’s lifetime, allowing scientists to track individuals across time and space.
“It’s encouraging to see this upward trend,” said lead author Andrew Pettit. “This growing dataset represents a major leap forward in understanding and protecting this iconic species.”
🔍 How Conservation Efforts Are Helping
Since the collapse of the fishery in the 1980s, California has implemented several protective measures:
- Gillnets banned within 3 nautical miles of the mainland and 1 nautical mile around the Channel Islands.
- Incidental catch limits reduced to just one fish per vessel per trip.
Although Mexico has yet to implement similar protections, these efforts in California appear to be making a difference. However, historical population levels were far higher—with over 4,500 fish landed annually in the 1930s alone.
📉 From 1994 to 2022, commercial gillnetters still caught an average of 126 giant sea bass per year, with 180 landed in 2022, highlighting ongoing risks.
🌊 Giant Sea Bass Behavior: Loyal Locals of the Reef
The photos also uncovered a remarkable trait: giant sea bass tend to stay near the same areas. Only a handful of fish were observed traveling over 30 miles, meaning these gentle giants are true homebodies.
This site fidelity has two implications:
- Positive for divers – They often encounter the same fish on return visits.
- Concerning for conservation – Limited movement means isolated populations are more vulnerable to local threats and have less genetic exchange.
🧬 Protecting key aggregation sites is essential for genetic diversity and long-term species recovery.
📲 Why Photo Identification Works So Well
Unlike traditional fish tagging, which is invasive and expensive, photo ID is low-cost, non-intrusive, and highly effective. The friendly nature of giant sea bass—often compared to “curious puppies”—makes them ideal candidates for this research method.
The study team included photos and videos from:
- Recreational divers
- Research expeditions
- Baited underwater cameras in deeper waters
- Incidental landings from commercial gillnetters
These diverse data sources confirmed the population growth trend and minimized sampling bias.
🤝 Expanding the Community Science Model
The Spotting Giant Sea Bass Project now has over 420 contributors and continues to grow. The research team plans to:
- Expand the project into Northern California and Mexico
- Make the dataset open-access
- Update the population database annually
🐠 Divers and ocean lovers are encouraged to submit their photos to help protect this majestic species.
✅ Key Takeaways
- Giant sea bass numbers in SoCal show signs of slow recovery.
- Over 1,200 adults were identified from 2015–2022 via photo-recognition.
- Community science played a crucial role in data collection.
- Ongoing threats include incidental catch and lack of protection in Mexican waters.
- Public participation is critical for the success of this conservation model.