by Bryan Jauregui, Todos Santos Eco Adventures
This article first appeared in Janice Kinne’s Journal del Pacifico
If they had a World Championship for Insult Hurling, China’s entry of “Son of a Turtle!” may not seem like obvious prize material. But a review of sea turtle reproductive habits reveals why the insult might be a contender: A female sea turtle will mate with several males prior to nesting season, storing the sperm of all her paramours in oviducts separate from her eggs for extended periods of time – sometimes years. When the time is right for nesting, her body will allow the sperm to fertilize the eggs, resulting in what scientists like to call “multiple paternity” for her offspring. In other words, little baby sea turtles have no idea who their daddies are. Get it?
But that is not the end of a sea turtle’s parental woes. While their mothers do contribute more than genetic material, it is a contribution so slim it resists the characterization of maternal. The female sea turtle will drag her enormous body (that’s about 100 pounds for olive ridleys and up to 2,000 pounds for leatherbacks) out of the ocean, find the perfect spot for her nest, dig a hole, deposit her eggs, cover them up, turn her (very large) back on them and return to the sea. And that’s it. No nest defending, no hatchling feeding, no primers on the sea turtle way of life. The females abandon their eggs to the nests they’ve prepared and let the world have its way. If the eggs are lucky enough to escape predators and the ravages of the sea, in 45 to 75 days (depending on the species) sea turtle hatchlings emerge, whereupon the vast majority promptly become part of the Great Circle of Life as bite-sized snacks for sea birds, fish and crabs. When Hobbes wrote that life is nasty, brutish and short, he quite possibly had sea turtles in mind.
And what of the survivors? Abandoned bastards clinging to seaweed patches with no familial guidance on how to survive. No wonder sea turtles grow up to be total loners with no urge to socialize beyond the mating drive. So what is it that makes a sea turtle’s life worth living? Meet Adelita. Adelita was a loggerhead turtle who was captured off the coast of Baja California as a juvenile and raised in captivity. When she was released in 1996 from a small Baja California town at a healthy 223 pounds, she was fitted with a tag to allow scientists to track her movements. And move she did! In fact, she covered the roughly 7,000 miles to the coast of Japan in just one year. Adelita’s journey was a strong datapoint in confirming scientists’ hypothesis that loggerhead sea turtle hatchlings ride the Great Pacific Turtle Gyre from Japan’s nesting beaches to the waters of Baja, where they spend their youth foraging and growing in the warm, food-rich environment. Then, when they reach sexual maturity at around 20-30 years of age, they return to Japan to mate and nest. Yep, that’s right, sea turtles are the ultimate road trippers!
All seven of the extant sea turtles species in the world – including the five that nest on the beaches of Baja – are road trippers, migrating between nesting and feeding grounds and
sampling all the delicacies and attractions in between. Representatives from Baja’s most abundant species, the olive ridley, have been observed by trans-Pacific ships over 2,400 miles from shore, enjoying the shrimp, lobsters, crab and fish of the tropical waters they like to inhabit. Another Baja nesting species, the hawksbill, has been known to travel almost 1,200 miles to dine on sponges and other invertebrates in tropical coral reefs and mangrove estuaries. And while those travel distances are impressive to be sure, the record is held by Baja’s most endangered sea turtle species, the leatherback, with some individuals logging 10,000 migratory miles.
Leatherbacks have been cruising the oceans’ great Turtle Gyres for 100 million years, consuming several hundred pounds of jelly fish per day, mainly in the jellyfish-rich zone within 1000 feet (300 meters) of the ocean’s surface. But leatherbacks have been observed doing something that only a few species of air-breathing marine animals are capable of achieving – diving over 3,000 feet (1,000 meters) into ocean basins. Over the millennia that they have been on earth, leatherbacks have evolved into diving dynamos, with collapsible lungs to avoid the bends, flexible shells to accommodate increased pressure at depth, and several other adaptations that allow them to go to great depths and stay there for a while. While there are many theories as to why they dive – escaping predators, looking for other food sources and so forth – a recent UK study using satellite transmitter-derived dive data has lead scientists to conclude that really they’re doing what any good sight-seeing road-tripper does – having a lark.
So it turns out that in spite of – or perhaps because of – their fraught beginnings, sea turtles actually lead a totally cool life, cruising the world’s oceans, visiting foreign lands, eating great food and getting spa treatments at turtle stations along the way, where “cleaner” fish and shrimp delicately clean up any algae and parasites they may have accumulated during their travels.
Hurray! The sea turtles are happy and having fun. But everyone knows it’s all about the homo sapiens on this planet, so when you ask Stephanie Rousso, a former Florida Fish and Wildlife Conservation biologist, Todos Santos Eco Adventures’ Wildlife Biologist, and co-founder of Alianza Keloni A.C., a sea turtle research organization in La Paz, why we should concern ourselves with sea turtles, she’s pretty clear that it’s just enlightened self interest for humans to do so. “Consider the leatherback.” says Stephanie. “Individuals can weigh as much as one ton, and leatherbacks eat their weight in jellyfish daily, making the leatherback one of the top jellyfish predators on the planet. With the huge decline in the number of leatherbacks, jellyfish have proliferated around the world, and in many places species dominance is shifting from fish to jellyfish as jellyfish eat fish eggs and larvae. So protecting leatherbacks is really just protecting a key food source for humans.” In other words, if you want to continue having your sushi, save a leatherback.
And that’s not all. “Hawksbills eat sponges on coral reefs, allowing the coral reefs to colonize and grow. Sponges have physical and chemical defenses that prevent most predators from eating them, but the hawksbill has no problem ripping the sponges to shreds. If the sponges were allowed to grow unchecked, they would eventually suffocate the coral reefs and greatly reduce the diversity of reef ecosystems. So protecting hawksbills is not only protecting diversity for the food supply, it also keeps the reefs healthy for human enjoyment.” In other words, if you want to continue enjoying your tropical snorkeling vacations, save a hawksbill.
Each of the seven turtle species has their specific role the planet, all contributing to the
natural balance and health of our ecosystems. They even help protect coastal communities from hurricanes. Stephanie explains. “When sea turtles lay their eggs on sandy beaches, all the nutrients found in the shells get into the sand. This helps make the beach a good environment for plants. Plants help hold the sand dunes in place, and the sand dunes help protect communities from hurricanes and storm surge.” The role of sand dunes has been demonstrated throughout history, most recently after Hurricane Sandy in New England, when researchers demonstrated in the academic journal Shore and Beach that areas protected by sand dunes were relatively unharmed, while those without barrier dunes suffered the greatest damage to structures and infrastructure. In other words, if want your coastal community to be standing after the next storm, save the nesting sea turtle species on your beaches.
So sea turtles help keep us fed, happy and safe from harm. Says Stephanie, only slightly tongue-in-cheek, “The world depends on sea turtles to keep on spinning.”
Yet the world is contributing to their rapid demise, and all seven sea turtle species are on the endangered species list in both the US and Mexico, as well as the red list of the International Union for the Conservation of Nature. The Sea Turtle Conservancy estimates that commercial fishing practices in the US contribute to the deaths of 250,000 sea turtles every year. And that’s just one nation. In Mexico, coastal development rivals fishing as the key threat to sea turtles, as the viability of their nesting beaches falls victim to poor, unregulated development practices. The problem is particularly acute in Baja California Sur, where tourism-related beach development is seen as key to economic success. The law in Mexico states that there can be no development within 20 meters of the high tide line, and this was thought to be sufficient protection for nesting sea turtles. But Stephanie, working with a grant from the prestigious Rufford Foundation, found something decidedly different in the nesting data she collected along a 21 kilometer stretch of beach north of Cabo San Lucas. She discovered that, on average, nests are 76.6 meters above the last officially recorded high tide line. In fact, 52% of nests are found 60 to 90 meters above the official high tide line, while only 22% are found within 30 meters, which includes the officially protected zone. For annual nesters like the olive ridley, this is not such a huge obstacle to overcome. But for more sporadic nesters like the leatherback – which nests every two to three years – this is an enormous problem and the leatherback population has declined 98% over the last two decades. If you’re a jellyfish, this is excellent news.
Turtles are loners, but that doesn’t mean that they always do things alone. Off the Pacific coast of Mexico for example, female olive ridley turtles will congregate just offshore. Then, on some cue currently known only to them, hundreds and sometimes thousands of them will come ashore at once and lay their eggs. Humans can take note. We don’t have to form groups, raise funds, have board meetings and act in concert to collectively respond to the threats to our environment. Each person can respond to their own environmental cues and make individual daily decisions that contribute to the conservation of sea turtles, their habitats and therefore ourselves: resist driving motorized vehicles on sea turtle nesting beaches even though it’s really fun; refrain from constructing buildings on or near sea turtle nesting beaches and sand dunes, even though it’s fabulous to be on the shore; and eliminate the use of plastic bags and bottles even though it’s super convenient to use them (Leatherbacks often mistake plastic bags for jellyfish). If each person acts solely on their own to address these problems, then collectively we can have an enormous impact. Of course, there will always be those who choose to ignore the environmental cues and act with little regard for the consequences, but it’s nobody’s fault but their own if the neighbors start referring to them as a Son of a Turtle!
Each summer Todos Santos Eco Adventures operates Sea Turtle Camp in association with our partners at ASUPMATOMA, one of the oldest sea turtle conservation groups in Baja California Sur. Volunteers have the opportunity to work with Stephanie Rousso and a group of Mexican biologists patrolling the beaches at night to look for nesting sea turtles, relocating the eggs to a protected corral, and often releasing mature hatchlings into the sea. This year the TOSEA Sea Turtle Camp will run August 27-September 5, and we recommend volunteering for only one night at a time. For more information please visit us at www.TOSEA.net or contact us at [email protected].
© Copyright Sergio and Bryan Jauregui, Casa Payaso S de RL de CV, 2016