On Tuesday, February 17, 2026, the San Diego Herpetological Society welcomed Dr. Jeffrey Seminoff, Leader of NOAA's Marine Turtle Ecology & Assessment Program at the Southwest Fisheries Science Center, for an engaging presentation on the biology and conservation of California's sea turtles. Blending captivating natural history stories with cutting-edge research findings, Dr. Seminoff offered our community an insider's perspective on how these ancient mariners are faring in our ocean backyard and around the world.

We extend our deepest gratitude to Dr. Seminoff for sharing his extraordinary expertise and passion. His dedication to sea turtle research and conservation since 1992 has fundamentally shaped our understanding of these iconic marine reptiles and advanced global efforts to protect them.

About Dr. Jeffrey Seminoff: A Leader in Sea Turtle Conservation

Dr. Jeffrey Seminoff is one of the world's preeminent sea turtle researchers, with over three decades of experience studying and protecting marine turtles throughout the Pacific Ocean. Since joining NOAA's Southwest Fisheries Science Center in La Jolla, California in 2002, Dr. Seminoff has led groundbreaking research that has transformed our understanding of sea turtle ecology, distribution, and conservation needs.

Dr. Seminoff's Distinguished Career:

• Leader, Marine Turtle Ecology & Assessment Program, NOAA Southwest Fisheries Science Center
• Ph.D. from the University of Arizona (2000)
• Post-doctoral Fellow at University of Florida's Archie Carr Center for Sea Turtle Research (2000-2002)
• Past President of the International Sea Turtle Society
• Host of the 31st International Symposium on Sea Turtle Biology and Conservation (San Diego, 2011)
• U.S. Delegate for the Scientific Committee of the Inter-American Convention for the Protection and Conservation of Sea Turtles
• Team Leader for green sea turtle status assessments for the IUCN Red List and U.S. Endangered Species Act
• Member of IUCN Marine Turtle Specialist Group and IUCN Tortoise and Freshwater Turtle Specialist Group
• Chief Editor of Chelonian Conservation and Biology
• Author of over 250 scientific publications and two books, including "Sea Turtles of the Eastern Pacific" (University of Arizona Press)
• Mentor to more than 50 graduate students in turtle research and conservation

Dr. Seminoff's current research focuses on innovative approaches including stable isotope analysis, biotelemetry, and aerial surveys to understand sea turtle life history throughout the Pacific. He is particularly dedicated to reducing fisheries bycatch in small-scale fisheries of Latin America and training the next generation of conservation scientists.

Sea Turtles in California Waters: Species, Distribution, and Ecology

California's coastal and offshore waters provide critical habitat for several species of sea turtles, despite being far from their tropical and subtropical nesting beaches. These ancient reptiles—some species virtually unchanged for 100 million years—undertake remarkable migrations and face numerous challenges in our modern oceans.

Five sea turtle species are found in California waters:

1. East Pacific Green Sea Turtle (Chelonia mydas) - Threatened

Green sea turtles are the most commonly observed sea turtles along California's coast and the northernmost resident population occurs in San Diego Bay. Despite their name, these turtles aren't particularly green—the name comes from the greenish color of their fat. They have heart-shaped shells, small heads, and single-clawed flippers. Juveniles and adults are present year-round in Southern California's bays, lagoons, and coastal inlets including San Diego Bay, Seal Beach National Wildlife Refuge, the San Gabriel River, and La Jolla Cove.

These turtles originate from nesting beaches in Michoacán, Mexico, and travel north to California to take advantage of productive coastal ecosystems rich in seagrass, eelgrass, and marine algae. Adults measure 3-4 feet in length and weigh 300-400 pounds. They are primarily herbivorous, feeding almost exclusively on vegetation as adults, though juveniles may eat invertebrates.

Green sea turtles represent one of the greatest conservation success stories in the eastern Pacific. After decades of legal harvest for their meat and eggs from the early 1900s through the early 1990s, the species has made a remarkable comeback thanks to nesting beach protections beginning in the late 1970s and foraging area protections starting in the mid-1990s. In 2025, the IUCN upgraded the global conservation status of green sea turtles from Endangered to Least Concern—a historic achievement reflecting decades of dedicated conservation work.

2. Loggerhead Sea Turtle (Caretta caretta) - Vulnerable

Loggerhead sea turtles are the largest hard-shelled turtles in the world, with some individuals weighing over 1,000 pounds. They are highly migratory and travel between tropical and temperate waters. Loggerheads are infrequent but regular visitors to Southern California, with their presence being somewhat ephemeral—aerial surveys in 2011 found no turtles, while surveys in 2015 estimated over 15,000 loggerheads in California waters.

These turtles hatch in Japan and the western Pacific, then drift and swim across the Pacific Ocean, spending decades along the Baja California coast before returning to nest in their natal areas. Their sporadic appearances in California waters are influenced by oceanographic conditions and prey availability.

3. Pacific Leatherback Sea Turtle (Dermochelys coriacea) - Critically Endangered / California State Marine Reptile

Leatherback sea turtles are the largest turtles and one of the largest living reptiles in the world, weighing up to 2,000 pounds and reaching 8 feet in length. Unlike other sea turtles, they have a soft, leathery shell instead of a hard carapace. These prehistoric giants undertake one of the longest migrations on Earth, crossing the Pacific Ocean from California to Indonesia—some 6,000 miles one way.

Leatherbacks can dive to depths of 4,000 feet and stay submerged for up to 85 minutes, though they typically surface every 5 minutes. They feed primarily on jellyfish and are drawn to California waters during summer months to take advantage of abundant jellyfish populations in the California Current. Despite millions of years on Earth, western Pacific leatherbacks are critically endangered, making them one of the world's most threatened marine animals. California designated the Pacific leatherback as the official State Marine Reptile in recognition of their importance to our coastal waters.

4. Olive Ridley Sea Turtle (Lepidochelys olivacea) - Vulnerable

Olive ridley sea turtles are the smallest of all sea turtles, measuring about 2-2.5 feet and weighing 80-110 pounds. Named for the olive color of their heart-shaped shells, these turtles typically prefer warmer waters but are occasionally found in California, particularly in areas like Greater Farallones National Marine Sanctuary. They sometimes gather in small groups, sunning on the water surface to warm themselves in cooler California waters. They feed on algae, fish, crabs, shellfish, and shrimp.

5. Hawksbill Sea Turtle (Eretmochelys imbricata) - Critically Endangered (Rare in California)

Hawksbill sea turtles are rare visitors to California waters. They are easily recognizable by their distinctive hawk-like beak and beautiful patterns on their shells and flippers. Unfortunately, this beauty has made them targets for the illegal tortoiseshell trade. Hawksbills prefer tropical waters and feed primarily on sponges found in coral reef environments.

Groundbreaking Research in Southern California

For over 20 years, NOAA's Southwest Fisheries Science Center has conducted intensive research on sea turtles in Southern California, particularly focusing on green sea turtles in San Diego Bay, Seal Beach National Wildlife Refuge, the San Gabriel River, and most recently, La Jolla Cove. This research, conducted in collaboration with local and federal agencies and universities including the Unified Port of San Diego, U.S. Navy, U.S. Fish and Wildlife Service, San Diego State University, Scripps Institution of Oceanography, and Long Beach State University, has revealed fascinating insights into sea turtle ecology in urban environments.

Key Research Findings:

• Green turtles in California originate from Mexican nesting beaches in Michoacán and the Galápagos Islands
• San Diego Bay hosts the northernmost year-round resident population of East Pacific green turtles
• Turtles coexist successfully with humans in highly urbanized environments, taking advantage of productive bay ecosystems
• Warm water effluent from power plants historically provided thermal refuges, attracting and concentrating turtle populations
• Turtles show distinct seasonal movement patterns, with increased activity during warmer months
• San Gabriel River monitoring from 2013-2021 documented year-round green turtle presence, particularly near Los Cerritos Wetlands and warm water discharge areas
• Green turtles feed on eelgrass, sea lettuce (Ulva lactuca), and other marine algae in California waters
• Citizen science observations have dramatically increased our understanding of turtle distribution and abundance
• Sex ratios, growth rates, and age at recruitment have been established for California populations
• Satellite telemetry and tracking studies reveal detailed movement patterns and habitat preferences

Conservation Challenges: Threats Facing Sea Turtles

While there is good news about sea turtle populations worldwide—particularly the remarkable recovery of green sea turtles—these ancient mariners still face significant threats that require ongoing conservation attention.

Primary Threats:

• Fisheries Bycatch: Accidental capture in fishing gear, particularly longlines, trawls, and gillnets, remains one of the most significant threats. Dr. Seminoff's current work focuses heavily on reducing bycatch in small-scale fisheries throughout Latin America.
• Entanglement in Marine Debris: Sea turtles become entangled in abandoned fishing gear ("ghost nets"), plastic debris, and other marine trash, leading to injury, drowning, or starvation.
• Boat Strikes: Collisions with boats and ships cause significant injuries and mortality, particularly in busy harbors, bays, and coastal areas where turtles forage.
• Coastal Power Plant Entrainment: Turtles attracted to warm water discharge areas near power plants can be entrained (sucked into) cooling water intake systems, causing injury or death.
• Habitat Loss and Degradation: Coastal development, pollution, and climate change degrade both nesting beaches and foraging habitats. Loss of seagrass beds and algae-rich areas directly impacts feeding grounds.
• Climate Change: Rising temperatures affect sand temperatures on nesting beaches, skewing sex ratios (warmer sand produces more females). Sea level rise threatens nesting beaches, and changing ocean conditions affect prey distribution and migration patterns.
• Illegal Harvest: In some regions, sea turtles and their eggs continue to be taken illegally for consumption or traditional use, despite protections.
• Pollution: Plastic ingestion, chemical contamination, and oil spills harm sea turtles. Turtles mistake plastic bags for jellyfish, leading to intestinal blockages and starvation.

Conservation Success Stories: Reasons for Hope

Dr. Seminoff's presentation highlighted remarkable conservation successes that demonstrate what can be achieved through dedicated research, protection measures, and international cooperation.

Major Conservation Achievements:

• Green Sea Turtle Recovery: The 2025 IUCN reclassification of green sea turtles from Endangered to Least Concern globally represents one of the greatest conservation success stories. Nesting numbers in Florida alone have increased from 94 nests in 1985 to 8,774 nests in 2025—a nearly 100-fold increase.
• Endangered Species Act Protections: All sea turtle species in U.S. waters are protected under the ESA, with NOAA Fisheries and U.S. Fish and Wildlife Service sharing conservation jurisdiction.
• Nesting Beach Protections: Beginning in the 1970s, protection of key nesting beaches in Mexico, Central America, and throughout the Pacific has allowed populations to recover.
• International Cooperation: The Inter-American Convention for the Protection and Conservation of Sea Turtles brings nations together to coordinate conservation across turtle migration routes.
• Bycatch Reduction Technology: Turtle Excluder Devices (TEDs) in trawl fisheries and modified fishing gear have significantly reduced mortality.
• Long-Term Monitoring Programs: Decades of consistent monitoring have provided the data needed to assess population trends and evaluate conservation effectiveness.
• Research Advancements: Innovations in satellite telemetry, genetic analysis, stable isotope studies, and aerial surveys have revolutionized our understanding of sea turtle movements, diet, and population connectivity.
• Community Engagement: Local communities in nesting areas have become conservation partners, protecting beaches and engaging in eco-tourism rather than turtle harvest.

How You Can Help Protect California's Sea Turtles

Sea turtle conservation requires ongoing support from scientists, policymakers, and the public. Here are ways you can make a difference:

1. Report Sea Turtle Sightings - Become a Citizen Scientist!

Your observations are invaluable for tracking where and when sea turtles occur in Pacific waters. If you see a sea turtle anywhere along the West Coast, please report it immediately:

NOAA West Coast Sea Turtle Sightings Survey: Report Your Sighting

The survey asks for basic information including date, time, location, species (if known), behavior, and photos if possible. This community science data helps researchers understand distribution patterns, seasonal movements, and population trends. With more eyes on the water and smartphones ready to document sightings, we're learning more about sea turtles in California than ever before!

2. Support Conservation Organizations

NOAA Fisheries - Marine Turtle Ecology & Assessment Program

Learn More: NOAA SWFSC Marine Turtle Program

Dr. Seminoff's program conducts cutting-edge research on sea turtle ecology, conservation, and management throughout the eastern Pacific.

Sea Turtle Conservancy

Website: https://conserveturtles.org/

The world's oldest sea turtle research and conservation organization, founded in 1959, working to protect sea turtles through research, advocacy, education, and protection of their natural habitats.

Turtle Island Restoration Network

Website: https://seaturtles.org/

Headquartered in California, this organization advocates for endangered sea turtles along the West Coast and worldwide, engaging the public through education and conservation programs.

Aquarium of the Pacific - Sea Turtle Monitoring Project

The Aquarium's Southern California Sea Turtle Monitoring Project uses citizen science volunteers to track green sea turtles in the San Gabriel River, contributing valuable data to conservation efforts.

3. Take Action in Your Daily Life

• Reduce plastic use and participate in beach cleanups to prevent marine debris
• Properly dispose of fishing line and gear—never abandon equipment in the ocean
• Use reef-safe sunscreen to protect marine ecosystems
• Choose sustainable seafood and support fisheries that use turtle-safe practices
• Slow down and watch for turtles when boating in turtle habitats
• Never disturb nesting sea turtles or hatchlings if traveling to nesting beaches
• Keep beaches dark at night near nesting areas (lights disorient hatchlings)
• Support marine protected areas and conservation policies
• Educate others about sea turtle conservation
• If you find a stranded, injured, or dead sea turtle, call NOAA's West Coast Stranding Hotline immediately

4. Learn More About Sea Turtles

NOAA Fisheries Sea Turtles: https://www.fisheries.noaa.gov/sea-turtles

Dr. Seminoff's Profile: https://www.fisheries.noaa.gov/contact/jeffrey-seminoff-phd

Faces of Sea Turtle Conservation - Jeff Seminoff: https://www.fisheries.noaa.gov/feature-story/faces-sea-turtle-conservation-jeff-seminoff-marine-ecologist

Why Sea Turtle Conservation Matters

Sea turtles have survived for over 100 million years, outliving the dinosaurs and adapting to countless environmental changes. They play vital ecological roles in marine ecosystems—grazing on seagrass beds keeps them healthy and productive, providing habitat for countless other species. Sea turtles transport nutrients between oceanic and coastal ecosystems, and their eggs and hatchlings provide food for numerous predators, supporting beach and dune ecosystems.

As Dr. Seminoff emphasized, sea turtles are also powerful indicators of ocean health. Their presence in an area signals productive, functioning marine ecosystems. Their struggles reveal the cumulative impacts of human activities on our oceans—from overfishing to climate change to plastic pollution.

Protecting sea turtles means protecting the ocean systems we all depend on. These ancient mariners connect us to our natural heritage and inspire wonder in people of all ages. Their remarkable recovery stories—particularly the green sea turtle's journey from endangered to least concern—demonstrate that conservation works when we commit to it.

Science, Community, and Hope

The San Diego Herpetological Society is honored to have hosted Dr. Jeffrey Seminoff and to support the critical work being done by NOAA's Marine Turtle Ecology & Assessment Program right here in San Diego. Dr. Seminoff's presentation reminded us that we are fortunate to live in a region where sea turtles swim in our bays, forage in our kelp forests, and migrate along our coastline.

The story of California's sea turtles is one of remarkable resilience and hard-won conservation success, tempered by ongoing challenges that require continued vigilance and action. Through rigorous science, thoughtful management, international cooperation, and public engagement, we can ensure that sea turtles continue to grace our Pacific waters for millions of years to come.

We encourage everyone to become part of this conservation story—report your turtle sightings, support conservation organizations, reduce your environmental footprint, and share your passion for these extraordinary animals with others. Together, we are all guardians of the Pacific.

Thank you, Dr. Seminoff, for your decades of dedication to sea turtle conservation and for sharing your knowledge with our community. Your work inspires us all to be better stewards of our ocean planet.

SEE A SEA TURTLE? Report it to NOAA's West Coast Sea Turtle Sightings Survey and become a citizen scientist today!

About the San Diego Herpetological Society

The San Diego Herpetological Society is dedicated to advancing the knowledge, appreciation, and conservation of reptiles and amphibians. We host monthly meetings featuring leading experts, educational programs, and conservation initiatives throughout San Diego County. Join us for our next meeting to connect with fellow herp enthusiasts and learn from world-class scientists!

For more information, visit: www.sdherpsociety.org

Additional Resources and Links

NOAA Marine Turtle Ecology & Assessment Program: https://www.fisheries.noaa.gov/west-coast/science-data/marine-turtle-ecology-assessment-research

Green Turtle Research in Southern California: https://www.fisheries.noaa.gov/west-coast/science-data/green-turtle-research-and-conservation-southern-california

Report Sea Turtle Sightings: swfsc.turtle-sightings@noaa.gov

U.S. Fish & Wildlife Service - Sea Turtles: https://www.fws.gov/program/sea-turtles

State of the World's Sea Turtles (SWOT): https://www.seaturtlestatus.org/

References

• NOAA Southwest Fisheries Science Center. Marine Turtle Ecology & Assessment Program.
• IUCN Red List of Threatened Species. (2025). Green Sea Turtle Assessment.
• Eguchi, T., et al. (2012). Morphology and growth rates of the green sea turtle in a northern-most temperate foraging ground. Herpetologica, 68:76-87.
• MacDonald, B., et al. (2012). Home ranges of East Pacific green turtles in a highly urbanized temperate foraging ground. Marine Ecology Progress Series, 461:211-221.
• Allen, C.D., et al. (2013). Migratory origin of loggerhead turtles in the southern California bight. Marine Ecology Progress Series, 472:275-285.
• California State Capitol Museum. Pacific Leatherback Sea Turtle - State Marine Reptile.
• U.S. Fish and Wildlife Service. Eastern Pacific Green Sea Turtle Species Profile.
• Aquarium of the Pacific. Southern California Sea Turtle Monitoring Project, San Gabriel River Data (2013-2021).