The Science of Sustainability

Various Voyages of Sea Turtles

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Leatherback turtle offshore of Moss Landing, California. Photographed by Michael Sack, Sanctuary Cruises

In October and November, three different species of sea turtles have been reported in Monterey Bay and the Gulf of the Farallones National Marine Sanctuary waters.

It's unusual for sea turtles to venture into temperate waters. Other species also visit  when surface waters warm up, and this fall has been unusually warm with surface temperatures approaching 60 degrees F.

In October, an olive ridley sea turtle beached itself in Pacific Grove. Riding along the warm counter currents, these turtles are sometimes “cold-stunned” when  the warmer currents disappear, stranding the turtles in colder bay waters. The turtle is currently being cared for at the Monterey Bay Aquarium until it can be returned to the wild.

The olive ridley sea turtle are considered the most abundant of the seven species, yet globally they have declined by more than 30% from historic levels. These turtles are considered endangered because of the loss of nesting sites in the world. The eastern Pacific turtles have been found to range from Baja California, Mexico to Chile. The nests of Pacific olive ridley are located around Costa Rica, Mexico, Nicaragua, and the Northern Indian Ocean; the breeding colony in Mexico was listed as endangered in the U.S. on July 28, 1978.

Early this month, a rare sighting of a green sea turtle was reported at the commercial wharf in Monterey. Local sea turtle experts positively identified a male green sea turtle from photos and videos. Green sea turtles are generally found south of San Diego, but have been sighted as far north as southern Alaska in the eastern Pacific.  This turtle was outside of its normal range, and is a very rare sighting this far north and especially so close to the shore.

The green turtle was listed under the Endangered Species Act on July 28, 1978. The breeding populations in Florida and the Pacific coast of Mexico are listed as endangered. In 2004, the International Union for Conservation of Nature (IUCN) listed the green sea turtle as an endangered species, worldwide.

More common to our local waters is the giant eastern Pacific leatherback  sea turtles. Leatherback sea turtles are the largest, deepest diving of all sea turtle species and are found swimming in all oceans across the globe.

Leatherback sea turtles in the Pacific Ocean are in far greater danger of extinction than Atlantic Ocean populations due to greater commercial fishing, illegal poaching, ocean pollution, and nesting beach destruction in the Pacific. Leatherbacks in the Pacific can be divided into two primary populations: those that nest in the eastern Pacific and those that nest in the west.

Leatherbacks in the eastern Pacific population primarily nest in Central America and spend most of their lives offshore of nesting beaches or migrating to foraging areas. The largest foraging area is off the shore of Chile in the southeastern Pacific. The corridor above the Cocos Ridge of seamounts is a migration area of critical importance to many species between Cocos Island and Easter Island. However, some nesting occurs in Mexico and foraging leatherbacks from the eastern Pacific population may venture into California waters to feed.

In 1990, the California State Legislature banned all longline fishing in the Exclusive Economic Zone (EEZ) to prevent the deaths of leatherbacks sea turtles. Then in 2008, the California Legislature passed Assembly Joint Resolution No. 62 (Leno) for west coast sea turtle protection, supporting efforts to preserve and recover Pacific leatherback populations.

The Marin non-profit organization, Sea Turtle Restoration Project’s (STRP),  is working to protect these and all species of endangered sea turtles. Their work has resulted in the National Marine Fisheries Service establishing critical habitats for the leatherback within much of the California, Oregon, and Washington EEZ.

In an effort to enhance recovery prospects for the critically endangered Pacific leatherback sea turtle, they initiated a “citizen scientist” research program as part of its volunteer Leatherback Watch Program.  The program tracks sightings of leatherbacks off the northern California coast, coordinating with recreational sailors, whale watchers, and scientists.  This region is an essential feeding area for leatherbacks that swim across the entire Pacific Ocean from nesting beaches to reach the abundant jellyfish blooms that occur each summer in the California Current marine ecosystem. This year,  the Leatherback Watch Program recorded over twenty sightings in our local waters.

We can also follow a live green sea turtle tagged by the researchers from the Sea Turtle Restoration Project. The scientists capture sea turtles off Cocos Island, an island 400 miles off the coast of Costa Rica. Brought aboard the vessel, the scientists weigh, measure, take blood and tissue for DNA analysis and equip the turtles with special satellite tags. These tags send a radio signal to a satellite and relay the position back to a computer.

Fillmore the Turtle by Jim Toomey.

Named Fillmore after cartoonist Jim Toomey’s comical creation, this real sea turtle’s wanderings can be followed on the STRP web site.  In the past week, Fillmore the Green sea turtle swam north then east, making it back into the protected "No Take" area 12 nautical miles around Cocos Island National Park.  Let's hope Fillmore makes it east to the nesting beaches without encountering long lines or plastic bags. Data indicates that 80 percent of the debris on our beaches and shorelines comes from inland sources, traveling through our storm drains or creeks out to the beaches and oceans.  When litter enters sea turtle feeding areas in the ocean, it can have deadly consequences for sea turtles that mistake the debris for food.

We can help protect these and other sea turtles by "Bagging the Plastics" and taking action to reduce the plastic waste polluting sea turtle feeding areas in the ocean.  Fillmore and other sea turtles can use your help by sending a letter to the Costa Rican president asking for more protections at Cocos Island National Park.

Until the battery on the radio transmitter dies, we can follow Fillmore’s voyage and his exploits. Maybe one day Fillmore’s counterparts will visit our Sanctuary in greater numbers in a conservation success story.

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Category: Biology, Environment

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David McGuire

About the Author ()

An avid writer, surfer and ocean voyager, David McGuire is the founder of the conservation non profit Sea Stewards and is an advocate for a healthy ocean. As Captain, Dive Master and Cinematographer, David has explored the world ocean on numerous sailing voyages collecting media with an emphasis on ocean awareness.Educated in Marine Biology, he holds a masters degree in Environmental Health and has worked in education and public health at the University of California at Berkeley for over a decade. David is the writer, producer and underwater cinematographer of the award winning documentary Sharks: Stewards of the Reef, and was writer and cinematographer on a film on California Marine Protected Areas, and Palmyra Atoll. David has written, filmed and produced a new documentary on the Sharks of San Francisco Bay and has worked as cameraman on feature films such as 180 South and A Beautiful Wave. His underwater filmwork on San Francisco elasmobranches and ecosystems continues and he frequently donates his work for conservation causes. As Field and Research Associate with the California Academy of Sciences, David is Project Manager of a shark research program on the San Francisco Bay and has initiated a new sharks awareness campaign: Shark Sanctuary San Francisco. Through expedition sailing and video production, Sea Stewards is exploring and explaining our ocean world, influencing policies and practices from sustainable fishing to marine protection. Through Sea Steward Studios, our Media Production work is used to influence sound policies and sustainable ocean practices. Current work includes a series on Sea Turtle Conservation in Mexico, a film with partners Team Fish Finders using local fishermen to promote catch and release and a documentary on local sustainable seafood and a Cordell Banks Expedition.