Baja California's Sea Turtles
Swim Out of the Past
For nearly 400 years, Spanish trading ships known as Manila Galleons left Asia loaded with porcelain, silk, spices and other treasures bound for the Port of Acapulco on what is today the west coast of Mexico. After three months at sea, the sailors would reach the coast of Baja California starved, scurvy-ridden, and with no naval escort. British and Dutch buccaneers knew of the treasure ships' vulnerability and waited in the protected waters of coves like Cabo San Lucas to assault the galleons and seize their riches.
Sea turtles were an important part of the buccaneer diet, mainly because they could be held alive, without water, for weeks or months at a time. The diaries of corsairs like Thomas Cavendish, Edward Cooke, and Woodes Rogers contain detailed descriptions of where, how, and how many turtles were caught on the stops between Lima and Cabo San Lucas. There, turtles were consumed as the privateers and sailors waited for the Manila ships.
Nearly four centuries later, the buccaneers' diaries would prove a valuable resource for understanding changes in the ocean, offering a glimpse of the ocean in the distant past. For example, recounting his time in the Marías Archipelago in the Gulf of California, privateer Edward Cooke wrote about how he and his crew "sometimes took 100 tortoises in one Night a-shore, and kept some of them six Weeks without Meat or Water. They are easily taken at Sea, when it is their breeding Time."
A map depicting the route of English privateer Sir Thomas Cavendish who famously looted the Spanish Galleon Santa Anna off the coast of Baja California.
By searching through the archives and the memories of fishermen living today, as well as scientific literature, I am trying to evaluate the changes in the population of the East Pacific Green Turtle, Chelonia mydas, in the central Baja California peninsula. At least as far as the chronology will take me. Looking into collective memory, the archaeological record, and gray literature—such as diaries, photographs, scientific reports, and travelers' journals—we can understand changes in the way humans relate to their environment.
Sir Thomas Cavendish. Johnstone's The Lives and Voyages of Drake, Cavendish, and Dampier.
The first humans to migrate to the Baja California peninsula encountered a vast, arid environment. Fresh water and edible plants were scarce, but rich seas provided ample food in the form of mollusks, fish, and, of course, sea turtles. Marine turtles are one of the most common taxa found in pre-historic sites, and by 6,000 B.P. the Cochimí people captured them with specialized harpoons and included marine turtles in burials and art, suggesting that their importance was both gastronomic and symbolic. The arrival of Spanish missionaries in the seventeenth century brought about massive changes: forced settling of a nomadic population, conflict, and diseases caused massive deaths and within less that two generations, most of the native population of Baja California had disappeared.
The establishment of the missions and the arrival of colonists from Europe and mainland New Spain brought about the establishment of a new society: the Californios, who lived spread across the desert in ranches and small communities. Given that they were easily caught and that an average juvenile East Pacific green turtle (Chelonia mydas) can feed up to twenty people, sea turtles had great cultural and material importance in these isolated desert outposts. Aside from being a staple food, they were also used for medicine and tanning. Eaten in soups, as salted jerky or roasted, they were consumed as much as two or three times a week in some communities.
Whaling in the Baja California lagoons in the mid-1800s left detailed records of sea turtle captures. Sea turtles provided sustenance on the whaling voyages and, as global whale stocks plummeted and voyages became less profitable, sea turtles could supplement meager earnings from sperm whale oil and rendered blubber. Captain Charles Scammon, a whaler and one of the first naturalists to make detailed descriptions of cetacean biology, describes the abundance of the Baja California lagoons stating that "the waters were alive with whales, porpoises, and fish of many varieties; turtle and seal basked upon the shores."
Scientists, such as the famed biologist André Agassiz, also visited the peninsula in the nineteenth century. In 1889, he reported a catch of 162 green turtles in a single haul of a seine, and "probably half as many more escaped from the seine before it could be beached; there being a continual loss by turtles crawling over the cork lines during the entire time."
Fishermen in a panga, 1970's. Courtesy of the Verdugo family of Bahía de los Ángeles, Baja California, Mexico.
An excerpt from Rogers' A Cruising Voyage Round the World.
Throughout the early twentieth century, sea turtles were captured for subsistence from wooden canoes powered by oars or paddles. On clear nights, harpooners would follow the bioluminescent stellae left by swimming turtles, rowing quietly and throwing the harpoon with just enough pressure to perforate the shell without breaking it. The weather, the tides, the small population, and the difficult art of harpooning all limited captures. Fishermen and scientists alike describe a great abundance of green turtles: on a good night, the only limit to catches was the size of the boat. David Caldwell, a marine biologist who worked in the peninsula in the early 1960s, reported seeing over 500 turtles landed over a three week period in the community of Bahía de los Ángeles. One fisher describes a particularly good night, when he and his crew captured around 120 turtles in a night with a single net. This abundance, however, would quickly change.
During the 1960s the economic growth of cities along the U.S.-Mexico border brought about a large demand for sea turtle dishes such as turtle soup (caldo de caguama) and turtle steaks (milanesas de caguama). This coincided with the introduction of off-board motors, sea turtle nets, and the first highway in the peninsula. The increase in demand, technology, and communication led to an exponential growth in sea turtle captures, bringing about a commercial collapse in the early 1980s. In contrast with the massive catches of the mid-twentieth century, for example, only around 300 turtles were captured in scientific monitoring conditions between 1994 and 2004, less than a month's landings in the early 1960s.
Seabirds. Credit: Michelle María Early Capistrán.
Turtle sketch by buccaneer Woodes Rogers.
Sea turtle captures have been banned in Mexico since 1990. Although sea turtle consumption and poaching are still common in some regions, populations of Chelonia mydas have been growing and are showing initial signs of recovery. However, in cases such as this where scientific data collection began after the target population was overfished, there is the risk of “shifting baseline syndrome,” where, for example, an older fisher in Baja California may have considered catches of 15 or 20 turtles a night to be a normal occurrence. In contrast, a younger fisher may have been accustomed to catching only 2 or 3 per trip, judging this level of abundance to be normal as well. In a similar manner, if scientific monitoring initiates after years or decades of exploitation—as in the case of sea turtles in Baja California—the baseline abundance may be that of a depleted population.
Although the population of Chelonia mydas has grown as compared to the populations levels in late 20th century, it must still be compared to a pre-exploitation baseline in order to evaluate its recovery. This situation is not unique to Baja California or to sea turtles.
Because scientific monitoring of many marine species is relatively recent in much of the world (rarely going back more than 40 or 50 years), there is a high risk of underestimating the past abundance of marine species and ecosystems. For this reason, it is critical to look into the past, both the scientific record and the collective memory of fishers, pirates, and whalers, in order to understand changes in the ocean.
The art of the harpoon: an interview with a sea turtle fisherman in Baja California. Credit: Michelle María Early Capistrán.
Though Michelle María Early Capistrán is a cultural anthropologist by training, the currents of the North Pacific led her to marine biology. She received a graduate degree in Ocean Sciences and Limnology at the National Autonomous University of Mexico (UNAM) and researches long-term human interactions with marine ecosystems by integrating ethnographic fieldwork, archival research and statistical analysis. She is author of the book Voces del Oleaje: ecología política de las tortugas marinas en la costa de Oaxaca. Follow her on Twitter @earlycapistran.