Growing up in the coastal state of Baja California Sur, Mexico, my main access to nature was the ocean, and I was lucky enough to live in an area with some of the richest marine biodiversity in the world. Eighty percent of marine mammals in the Pacific Ocean come to feed near my hometown in the Sea of California, with up to 40 blue whales feeding in a single location – imagine the ocean’s productivity delivering tons of krill, their only prey!
The ocean supported my family’s livelihood. My grandfather was the captain of two fishing boats and my grandmother was the president of the local fish cooperative. I have vivid memories of my uncle taking me out on his fishing boat five miles off the coast where we would watch loggerhead turtles rise to the surface. When multitudes of loggerheads surfaced simultaneously, bubbles would form in the water, and we would watch the ocean “boil.”
We didn’t know it at the time, but this phrase – “watching the ocean boil” – that we used figuratively would one day become literal. And the many sea turtles that I loved watching would dwindle in numbers over time.
Today, climate change sets and then breaks records for the hottest ocean temperatures, pollution and disease spread plastic and sickness to marine species, and beach erosion destroys habitats along coastlines. The oceans are in trouble because of human impacts, and only 7.5% of marine habitats (the size of North America) are protected, leaving ecosystems and the species that depend on them vulnerable.
All seven species of sea turtles are currently endangered. Sea turtles reflect the presence of environmental contaminants and emerging infectious diseases, making them sentinel species. Because sea turtles occupy both land and sea, they move in and out of infected or polluted areas and spread pathogens and contaminants geographically and through the food chain.
I have been fortunate enough to study sea turtles and their pathogens throughout my career as a wildlife veterinarian and later as a wildlife epidemiologist. I have traveled worldwide to study foxes in Patagonia, manatees in Belize, La Plata dolphins in Argentina, and sea turtles in Australia, Hawaii, and Mexico.
While in Hawaii in the ‘90s, I encountered a disease called fibro papillomatosis, a tumor that causes lesions in the skin and appendages on internal organs. Some of those tumors may become malignant as fibrosacomas in the tomium of sea turtles, ultimately growing into their bones. This disease is not limited to populations found off the coast of Hawaii; it has been documented across all oceans in Australia, Florida, Brazil, Chile, Southeast Asia, and Western Africa. This is likely because sea turtles have some of the largest migratory routes of marine animals, meaning any disease they carry has the potential for pantropical distribution.
I also observed sea turtles returning year after year to the beaches where they were born to lay their eggs. A female sea turtle can lay 100 eggs at a time and 1,000-10,000 eggs in a season; yet, only one out of those hatchlings will make it to adulthood.
Not only does beach erosion make it difficult for females to find areas to lay their eggs, but light pollution also impacts newly hatched sea turtles, obscuring their way to the ocean and leaving them more vulnerable to predators like gulls and crabs. If a hatchling does make it into the ocean and survives to adulthood, there’s a good chance that it will be illegally harvested or caught in nets that aren’t meant for it.
This phenomenon – called bycatch – is one of the biggest threats to marine life, especially the loggerhead turtle. Fishers often use large fishing nets that stretch a mile across the water to maximize their catch. However, sea turtles and other unwanted marine species can easily get caught in these nets, and unable to free themselves, they eventually drown and wash up to the beach.
Given these hosts of problems that sea turtles face, it is no surprise that this species is in trouble, and if the sea turtle is in trouble, then our oceans are in trouble. So, what can we do about it?
As a conservationist, I’ve tried all sorts of solutions, including writing to the Mexican government, asking them to do something about bycatch; working with groups who have introduced a technique to monitor sea turtle bycatch, the Turtle Excluder Device, that allows fishers to avoid sea turtles in their nets; and assisting nonprofits, including Sea Turtle Conservation Network of Californias, to tackle conservation issues. But still, these actions are not enough.
One of the reasons why sea turtle conservation has been so difficult to manage is culture. In Latin America, see turtle meat and eggs are believed to act as aphrodisiacs if consumed. Even as a young child, my grandfather used to make me drink sea turtle blood for medicinal reasons. Despite Mexico outlawing sea turtle consumption in the 1990s and creative marketing campaigns creating stigmas against sea turtle consumption, many coastal residents continue to eat sea turtles.
Oceans connect all of us, so the best way to tackle this issue is through transdisciplinary solutions that are supported by the public, stakeholders, and decision-makers and can be enacted on global and local levels. Recently, through One Health, I have worked on a campaign that combines education, conservation and human health. By demonstrating the dangers of eating sea turtles – which include ingesting heavy metals and toxins that can lead to cancer – the hope is that the public will stop eating sea turtles.
I look forward to measuring the outcomes of this new campaign, but in the meantime, on World Oceans Day and every day, I hope we can all continue to learn more about marine species, improve our policies to address harmful human impacts on our oceans, and explore new depths together.
Sea turtles are telling us what’s happening to the oceans, and it’s time we listen. The health of our marine environment depends on it.
A. Alonso Aguirre is the Dean of Warner College of Natural Resources.