Sea Turtle Nesting Expansion into Peru Brings New Management Challenges

Olive ridleys are nesting in increasing numbers in northern Peru, extending their nesting range south in the American Pacific. © Roderic Mast

Olive ridleys are nesting in increasing numbers in northern Peru, extending their nesting range south in the American Pacific. © Roderic Mast

By Shaleyla Kelez and Ximena Velez-Zuazo

Five sea turtle species are known to occur regularly in Peru’s waters and, rightfully, it is in the water that most Peruvian sea turtle research has taken place. For the most part, sea turtle nesting in Peru has been considered an extremely rare event. Before 2000, there had been only a single published account of sea turtle nesting in Peru; in 1979, one olive ridley nest was recorded in the northernmost tip of the country, in Tumbes, just a few meters south of the border with Ecuador. The prevailing notion was that Peru is too far south—too cold—for successful sea turtle nesting. But with only one nesting event on record, very little was truly known about sea turtle nesting in Peru.

In 2000, ecOceanica decided that to effectively study and conserve sea turtles in Peru, we needed to know for certain whether they nest, or used to nest, along our shores. So, traveling by truck, by motorcycle, and on foot, we visited 57 sites scattered along the entire 3,000- kilometer (1,864-mile) Peruvian coastline to gather information about the presence of sea turtles. In 47 places, we interviewed local residents, and in five of those places we were told that sea turtles used to nest nearby, though no further evidence was provided. That same year, a Peruvian fisherman brought olive ridley hatchlings to a nearby crocodile farm, but the origin of the hatchlings was unclear. So we continued to believe that Peru was not a regular nesting site for sea turtles, but rather was home to only rare nesting events.

It was not until 2007 that another sea turtle nest was reported, again an olive ridley, this time in the northwestern region of Piura, just south of the location of the 1979 record. This nest was followed in 2008 by another olive ridley nest in Tumbes, making us, and other organizations, start paying closer attention to nesting activity in Tumbes and Piura. By 2010 a few more nests were recorded in sites even farther south, indicating southward expansion of olive ridley nesting distribution limits in the eastern Pacific Ocean. But it is only in the past three years (2011–2013) that sea turtle nests have begun to occur more frequently, always in these two northernmost departments of Peru (with the exception of one green turtle nest in 2013 found even farther south in Lambayeque). The olive ridley has been, by far, the most commonly reported species nesting in Peru, but green turtle nests have also been observed with increasing frequency.

A total of about 70 nests and nesting emergences were recorded from January 2010 through February 2014, providing needed information about the reproductive biology and ecology of sea turtles in Peru. We are beginning to identify the most popular nesting beaches and to gain a better understanding of breeding seasons, average numbers of eggs per clutch, incubation times, and hatching and emergence success.

Shaleyla Kelez interviews a local resident about the presence of sea turtles during a survey of Peru’s coastline. © ecOceanica

Shaleyla Kelez interviews a local resident about the presence of sea turtles during a survey of Peru’s coastline. © ecOceanica

There are a few theories as to why sea turtle nesting is on the rise in Peru, and, in fact, the cause may be a combination of several factors. First, we are monitoring sea turtle nesting much more closely now than even a few years ago, which may be resulting in higher reporting. Second, eastern Pacific populations of olive ridleys have recovered substantially in recent years, and green turtles also appear to be increasing, which may be resulting in a higher number of “fringe” nesting events. It is also possible that a loss of suitable nesting habitat in other areas is causing the turtles to seek new nesting sites. Finally, warming land and sea temperatures may be allowing the turtles to expand farther south into habitats now suitable for nesting.

At this point, not enough evidence has been collected to determine the precise causes of the increase in sea turtle nesting in Peru. What we do know is that with the rise in nesting comes a new and difficult challenge—to manage the northern coast of Peru, which used to be relatively uninhabited but is now an almost continuous development of beachfront houses and hotels. Because the presence of nesting turtles was not previously known, coastal development has not taken into account the impact on sea turtle nests and hatchlings. Many beachfront houses and hotels have been or are being built over the dunes, or where the dunes used to be before they were removed, as well as very close to the water. These practices are causing erosion that, when combined with future scenarios of rising sea level, may cause the reduction or complete loss of some beaches. At the same time, critical attention is needed to address artificial lighting on the beaches, which can deter nesting females and disorient emerging hatchlings.

In 2000, we knew almost nothing about sea turtle nesting in Peru. We now know not only that turtles regularly nest in Peru, but also that nesting appears to be on the rise. Although the causes of this welcome increase still remain uncertain, we know that it brings new management challenges that must be addressed. Greater awareness, citizen participation in science, and revised legislation are all urgently needed. Now that we know Peru is home to the southernmost nesting of sea turtles in the eastern Pacific, we need to respond responsibly.