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| Subspecies: | Unknown |
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| Est. World Population: | |
| CITES Status: | NOT LISTED |
| IUCN Status: | Critically Endangered |
| U.S. ESA Status: | NOT LISTED |
| Body Length: | |
| Tail Length: | |
| Shoulder Height: | |
| Weight: | |
| Top Speed: | |
| Jumping Ability: | (Horizontal) |
| Life Span: | in the Wild |
| Life Span: | in Captivity |
| Sexual Maturity: | (Females) |
| Sexual Maturity: | (Males) |
| Litter Size: | |
| Gestation Period: | |
Habitat:
Habitats
Hawksbills nest on insular and mainland sandy beaches throughout the tropics and subtropics. They are highly migratory and use a wide range of broadly separated localities and habitats during their lifetimes (for review see Witzell 1983). Available data indicate that newly emerged hatchlings enter the sea and are carried by offshore currents into major gyre systems where they remain until reaching a carapace length of some 20 to 30 cm. At that point they recruit into a neritic developmental foraging habitat that may comprise coral reefs or other hard bottom habitats, sea grass, algal beds, or mangrove bays and creeks (Musick and Limpus 1997) or mud flats (R. von Brandis unpubl. data). As they increase in size, immature Hawksbills typically inhabit a series of developmental habitats, with some tendency for larger turtles to inhabit deeper sites (van Dam and Diez 1997, Bowen et al. 2007). Once sexually mature, they undertake breeding migrations between foraging grounds and breeding areas at intervals of several years (Witzell 1983, Dobbs et al. 1999, Mortimer and Bresson 1999). Global population genetic studies have demonstrated the tendency of female sea turtles to return to breed at their natal rookery (Bowen and Karl 1997), even though as juveniles they may have foraged at developmental habitats located hundreds or thousands of kilometers from the natal beach. While Hawksbills undertake long migrations, some portion of immature animals may settle into foraging habitats near their beaches of origin (Bowen et al. 2007).
Roles in the Ecosystem
Like other species of sea turtles, Hawksbills contribute to marine and coastal food webs and transport nutrients within the oceans (Bouchard and Bjorndal 2000). Hawksbills are important components of healthy coral reef ecosystems and are primarily spongivorous in the Caribbean (Meylan 1988), but more omnivorous in the Indo-Pacific (review by Bjorndal 1997). They consume relatively large amounts of algae in northern Australia (Whiting 2000 cited in S. Whiting in litt. to J. Mortimer 4 Jun 2007), soft corals in the Great Barrier Reef region (C. Limpus unpublished data), and other combinations of forage depending on habitat (in Seychelles, J. Mortimer and R. von Brandis unpublished data; in Barbados, B. Krueger unpublished data). At sites where they are primarily spongivorous, Hawksbills have been found to support healthy reefs by controlling sponges which would otherwise out-compete reef-building corals for space (Hill 1998, León and Bjorndal 2002, Bjorndal and Jackson 2003).
Hawksbills nest on insular and mainland sandy beaches throughout the tropics and subtropics. They are highly migratory and use a wide range of broadly separated localities and habitats during their lifetimes (for review see Witzell 1983). Available data indicate that newly emerged hatchlings enter the sea and are carried by offshore currents into major gyre systems where they remain until reaching a carapace length of some 20 to 30 cm. At that point they recruit into a neritic developmental foraging habitat that may comprise coral reefs or other hard bottom habitats, sea grass, algal beds, or mangrove bays and creeks (Musick and Limpus 1997) or mud flats (R. von Brandis unpubl. data). As they increase in size, immature Hawksbills typically inhabit a series of developmental habitats, with some tendency for larger turtles to inhabit deeper sites (van Dam and Diez 1997, Bowen et al. 2007). Once sexually mature, they undertake breeding migrations between foraging grounds and breeding areas at intervals of several years (Witzell 1983, Dobbs et al. 1999, Mortimer and Bresson 1999). Global population genetic studies have demonstrated the tendency of female sea turtles to return to breed at their natal rookery (Bowen and Karl 1997), even though as juveniles they may have foraged at developmental habitats located hundreds or thousands of kilometers from the natal beach. While Hawksbills undertake long migrations, some portion of immature animals may settle into foraging habitats near their beaches of origin (Bowen et al. 2007).
Roles in the Ecosystem
Like other species of sea turtles, Hawksbills contribute to marine and coastal food webs and transport nutrients within the oceans (Bouchard and Bjorndal 2000). Hawksbills are important components of healthy coral reef ecosystems and are primarily spongivorous in the Caribbean (Meylan 1988), but more omnivorous in the Indo-Pacific (review by Bjorndal 1997). They consume relatively large amounts of algae in northern Australia (Whiting 2000 cited in S. Whiting in litt. to J. Mortimer 4 Jun 2007), soft corals in the Great Barrier Reef region (C. Limpus unpublished data), and other combinations of forage depending on habitat (in Seychelles, J. Mortimer and R. von Brandis unpublished data; in Barbados, B. Krueger unpublished data). At sites where they are primarily spongivorous, Hawksbills have been found to support healthy reefs by controlling sponges which would otherwise out-compete reef-building corals for space (Hill 1998, León and Bjorndal 2002, Bjorndal and Jackson 2003).
Range:
The Hawksbill has a circumglobal distribution throughout tropical and, to a lesser extent, subtropical waters of the Atlantic Ocean, Indian Ocean, and Pacific Ocean. Hawksbills are migratory and individuals undertake complex movements through geographically disparate habitats during their lifetimes. Hawksbill nesting occurs in at least 70 countries, although much of it now only at low densities. Their movements within the marine environment are less understood, but Hawksbills are believed to inhabit coastal waters in more than 108 countries (Groombridge and Luxmoore 1989, Baillie and Groombridge 1996; see Regional Overviews in Supplementary Material).
Conservation:
The measures briefly described below are dealt with in greater detail in the Regional Overviews (see Supplementary Material).
- Treaties and Agreements. Hawksbills benefit globally from inclusion in CITES, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (listed on Appendix I) and CMS, the Convention on Migratory Species (listed on Appendices I and II). Regional agreements also help to conserve Hawksbills and their habitats (see Regional Summaries, Appendix II).
- Public Awareness. Interest in Hawksbills and other species of marine turtles is at an all-time high around the world. Interest in ecotourism is growing.
- Capacity building. Increasing numbers of biologists and conservationists focusing on sea turtles around the world benefit hawksbills.
- Protected Areas. Nesting and foraging sanctuaries protect Hawksbills although effective enforcement remains an elusive goal in many.
- Legislation and Enforcement. Numerous countries have temporarily or permanently banned all exploitation of sea turtles and their eggs and are attempting to improve enforcement of international bans on the tortoiseshell trade.
References:
McKeown, Sean. A Field Guide to Reptiles and Amphibians in the Hawaiian Islands. Diamond Head Publishing Company, 1996