Global Status of the Hawksbill Sea Turtle

Issue 3, 2007 Articles:

* Global Status of the Hawksbill Sea Turtle
* The Tortoiseshell Trade

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Global Status of the Hawksbill Sea Turtle

By Marydele Donnelly & Dr. Jeanne A. Mortimer


The hawksbill (Eretmochelys imbricata) is one of the world’s most endangered sea turtles. Hunted intensely for their beautiful shells since ancient times, hawksbill populations declined dramatically during the 20th century. Nearly 40 years ago, troubled by the effects of trade and the loss of nesting populations in the Caribbean and elsewhere, Dr. Archie Carr aroused scientific and public opinion about the hawksbill’s poor prospects for survival through a series of publications. In 1977, in recognition of the species’ plight, the international tortoiseshell trade was prohibited by the Convention on International Trade in Endangered Species (CITES), shortly after the treaty came into force. Hawksbills benefited substantially as the ban became widespread over time although even today, in many areas, hawksbills still are exploited for eggs, meat, and shell. Hawksbills also face a multitude of insidious and destructive modern threats, including the loss of nesting habitat caused by unregulated coastal development and erosion resulting from sea level rise. Hawksbill foraging habitat is threatened by loss of coral reefs caused by elevated sea temperatures as well as various types of marine pollution. Incidental capture in fisheries is also a problem for all species of sea turtles.

Recently, CCC participated in the production of the 2007 IUCN Red List Status Assessment for the Hawksbill Turtle, an in-depth review undertaken on behalf of the Marine Turtle Specialist Group by Dr. Jeanne Mortimer (CCC Scientific Advisor) and Marydele Donnelly (CCC staff). With a focus on changes in nesting populations over time, the assessment analyzed historic and recently published and unpublished accounts. This review unearthed intriguing information that provides a glimpse into a vanished world of abundance, including appeals for hawksbill conservation that were ignored almost a century ago. The 2007 analyses of populations at 25 Index Sites around the world show a decline of 88.3 to 90.8% in the number of females nesting annually over the last three hawksbill generations (105 years in the Atlantic and 135 years in the Indo-Pacific). Additional information on current trends in nesting and estimated populations in 58 countries, and the factors influencing them, is also presented. Based on their quantitative analyses, which demonstrate that hawksbill nesting has declined by at least 80% over the last 105-135 years, the authors recommended IUCN maintain the Critically Endangered listing for hawksbills. The assessment is currently under review.

The hawksbill is the most tropical of the world’s sea turtles. Hawksbills currently nest in at least 70 countries, often at low densities, and are found in the waters of 108 countries. Substantive population declines occurred in all ocean basins in the 19th and 20th Centuries, driven largely by the tortoiseshell trade. From 1950-1992 nearly two million hawksbills were killed for the Japanese trade alone. Although imports have ceased, the Japanese bekko (tortoiseshell) industry remains intact and continues to utilize its stockpile of shell. Earlier this year, the Japanese bekko associations publicly expressed their dismay that Cuba did not seek to overturn the international ban on tortoiseshell at CITES in June.

Today only a few large populations (500-1,000 females nesting annually) can still be found in the Indo-Pacific and Atlantic Oceans. Many populations are depleted or remnants of their former size. In many areas, researchers will never know the full extent of the declines that have taken place in the last several hundred years.

Thousands of females still nest in Australia, but such abundance is the exception rather than the rule. None of the world’s larger populations are free of threat. Hawksbills are heavily exploited and declining in Madagascar and the Maldives; their status in Iran is unknown but substantial numbers have been killed accidentally there by fisheries. Where they are protected in the Seychelles, nesting populations are increasing but overall nesting has declined during the past two decades. Aboriginal egg collection, environmental impacts associated with the oil and gas industry, and intense exploitation in international waters are taking a toll on Australia’s very substantial populations. Tragically, the most significant decline of the 20th century has occurred in Indonesia, historically the world’s most famous waters for tortoiseshell. In the Atlantic, after more than a decade of dramatic increase, hawksbill nesting in Mexico’s Yucatan Peninsula has fallen steeply.

In May, 2007, Indonesian customs officials discovered 296 hawksbill sea turtles that had been killed and preserved aboard a Chinese fishing vessel. Information and photo provided by Nono Rachmad Basuki of the Turtle Foundation.

On a global scale, threats to hawksbills vary by region. Egg exploitation is prevalent in many parts of the world, but it is especially pervasive in Southeast Asia where a culture of eating sea turtle eggs is well-established, with collection often approaching 100%. Capture at sea, both accidental and purposeful, is also an enormous problem in SE Asia where many thousands of large and small boats operate. Hawksbills have been relatively less exploited in the Northwest Indian Ocean in the Arabian Gulf, Arabian Sea, and the Red Sea, but activities associated with the oil and gas industry, coupled with unusually high water temperatures in recent years, have adversely impacted the region’s nesting habitat and coral reef foraging areas. There is evidence that oil pollution may have a greater direct impact on hawksbills than on other species of sea turtles. In the Southwest Atlantic, hawksbills have hybridized with loggerheads as hawksbill populations declined; the presence of adult female hybrids on Brazilian nesting beaches and viable offspring demonstrate that hybridization will continue. In many parts of the world adult and juvenile hawksbills are still killed for meat and are even used as shark bait. Fishermen who target lobster and reef fish will often take hawksbills when they encounter them. Although hawksbills are less common as bycatch in industrial fisheries, they are particularly susceptible to entanglement in gill nets and on fishing hooks. Such bycatch, although extensive, tends to go unreported because it results from the activities of the world’s small-scale fishermen.

The rapid development of tropical coastlines, especially for tourism, is causing extensive destruction of nesting habitat. Because hawksbills prefer to nest under vegetation, they are particularly affected by beachfront development and the clearing of dune vegetation. Similarly, the loss and destruction of foraging habitat is a significant threat. Hawksbills are typically associated with coral reefs, which are among the world’s most endangered marine ecosystems. Climate change has led to massive coral bleaching events with permanent consequences for local habitats. Poor water quality as a result of adjacent coastal development also is problematic.

On the brighter side, increases in hawksbill populations also have occurred as a result of long-term protection, conservation and regional collaboration in both terrestrial and marine habitats. Thanks to the ban on international trade regulated by CITES, some populations have stabilized, and others are now increasing, most notably in the Caribbean at Antigua (Jumby Bay), Barbados, Cuba (Doce Leguas Cays), Mexico (Yucatan Peninsula), Puerto Rico (Mona Island), and US Virgin Islands (Buck Island Reef Nat’l Monument). Increases in the Caribbean also coincide with dramatic reductions in the foraging ground harvest by Cuba which has, in effect, spared more than 55,000 large hawksbills since 1992. In the early 1990s world opinion and the threat of a U.S. fish embargo forced Japan, Cuba’s only tortoiseshell market, to stop importing shell. Subsequently, Cuba reduced its annual fishery quota from 5,000 to 500 hawksbills. Cuba recently announced that in 2008 it will establish a voluntary moratorium on the fishery.

Seychelles, in the Indian Ocean, is one of the few places in the world where records of long-term monitoring of both protected and unprotected beaches are available. For the 22 inner islands of Seychelles, monitoring was conducted at all islands in the early 1980s and the early 2000s. Nesting populations at the two islands that had been well-protected since the 1970s increased by 389% over 20 years, while nesting populations at 13 islands that had received no protection prior to 1994 declined by 59% during the same period. When all 22 inner islands are considered together, there was an overall decline of ~24% in the total nesting population over the two decades. Given that all 22 islands now enjoy high levels of protection, however, population increases are expected in the coming years.

Protection and documented increases provide hope for the future if governments and others commit effort and funds for hawksbill protection and conservation. CCC’s programs in support of hawksbill conservation will continue.

By Marydele Donnelly & Dr. Jeanne A. Mortimer. Marydele is CCC’s Director of International Policy, Jeanne is on CCC’s Scientific Advisory Board