Hawksbill Turtles, Seychelles
The Foraging Ecology of Hawksbill Turtles (Eretmochelys imbricata) at D’Arros Island, Republic of Seychelles
TURTLE SCIENTIST
Rainer von Brandis (under supervision of Dr. Jeanne Mortimer)
In association with D’Arros Research Centre
THE NEED FOR RESEARCH
Due to the diminished numbers of hawksbill turtles worldwide and the difficulties associated with conducting research in aquatic habitats, foraging populations have been poorly studied and basic information regarding foraging hawksbill populations is lacking. This is especially true for the western Indian Ocean since no baseline data concerning basic elements such as diet selection have been published. As a result, managers of marine protected areas are not able to manage foraging hawksbill populations effectively and do not make adequate provision for their conservation. The publication of the results from this study will provide some basic guidelines in this regard. An understanding of their diet will permit stakeholders to strategically position new MPAs to include hawksbill foraging habitat.
The role of hawksbill turtles on reef ecosystems is also poorly understood and in light of recent findings, significantly underestimated. Hawksbills have strong beaks and flippers and are often seen ripping up the reef in an attempt to locate cryptic food items. Several components of the ecosystem benefit from this type of activity. For instance, sponge eating and carnivorous fishes swarm around the heads of feeding turtles as they expose food. Even though preferred food items are relatively evenly distributed on the reef, turtles avoid some areas (such as colonies of branching or plate corals) and are more active in others. In so doing, hawksbills promote a patchy pattern of habitat development, which in turn, supports higher levels of biodiversity. Findings also suggest that hawksbills create and maintain micro-habitat diversity on coral reefs. Feeding scars left behind by hawksbills include small caves and holes in the reef, which provide both food and shelter for smaller sessile or mobile organisms. Through this projects publications SOSF hopes to elevate the ecological importance of hawksbill turtles on the scientific arena.
PROJECT SUMMARY
D’Arros Island has been protected for many years and due to the resultant higher densities of hawksbill turtles, presents a unique opportunity to collect baseline data describing the foraging ecology of this critically endangered species. In order to complete the final data collection phase and to promote public awareness of hawksbill turtle conservation, underwater photographic equipment is required. Over 200 hours of in-water data collection has resulted in the habituation of 8 turtles on a single insular reef. These turtles show little sign of alarm in the presence of divers and a unique opportunity exists to photographically document their natural behaviour. The photographic equipment is also required to develop turtle identikits, catalogue prey items, document foraging behaviour and to monitor their feeding habitats.
OBJECTIVES
• To quantify the nature and extent of foraging hawksbill turtle presence at the D’Arros/St. Joseph system.
• To describe the feeding ecology of hawksbill turtles at the D’Arros/St. Joseph system.
• To estimate the conservation status of hawksbill turtles at the St. Joseph system.
o Are there any current threats to this population?
o Does food availability affect population growth?
o Do recent coral bleaching events affect foraging hawksbills?
SPECIFIC CONSERVATION AIMS
TO PROMOTE THE PROTECTION AND CONSERVATION STATUS OF HAWKSBILL TURTLES
• To provide decision support for stakeholders involved with the conservation and management of foraging hawksbill populations
• To promote the ecological value of hawksbill turtles on the scientific arena
• To promote the economical value of hawksbill turtles through non-consumptive use
• To promote public awareness amongst consumers of hawksbill products
TURTLE SCIENTIST
Rainer von Brandis (under supervision of Dr. Jeanne Mortimer)
In association with D’Arros Research Centre
THE NEED FOR RESEARCH
Due to the diminished numbers of hawksbill turtles worldwide and the difficulties associated with conducting research in aquatic habitats, foraging populations have been poorly studied and basic information regarding foraging hawksbill populations is lacking. This is especially true for the western Indian Ocean since no baseline data concerning basic elements such as diet selection have been published. As a result, managers of marine protected areas are not able to manage foraging hawksbill populations effectively and do not make adequate provision for their conservation. The publication of the results from this study will provide some basic guidelines in this regard. An understanding of their diet will permit stakeholders to strategically position new MPAs to include hawksbill foraging habitat.
The role of hawksbill turtles on reef ecosystems is also poorly understood and in light of recent findings, significantly underestimated. Hawksbills have strong beaks and flippers and are often seen ripping up the reef in an attempt to locate cryptic food items. Several components of the ecosystem benefit from this type of activity. For instance, sponge eating and carnivorous fishes swarm around the heads of feeding turtles as they expose food. Even though preferred food items are relatively evenly distributed on the reef, turtles avoid some areas (such as colonies of branching or plate corals) and are more active in others. In so doing, hawksbills promote a patchy pattern of habitat development, which in turn, supports higher levels of biodiversity. Findings also suggest that hawksbills create and maintain micro-habitat diversity on coral reefs. Feeding scars left behind by hawksbills include small caves and holes in the reef, which provide both food and shelter for smaller sessile or mobile organisms. Through this projects publications SOSF hopes to elevate the ecological importance of hawksbill turtles on the scientific arena.
PROJECT SUMMARY
D’Arros Island has been protected for many years and due to the resultant higher densities of hawksbill turtles, presents a unique opportunity to collect baseline data describing the foraging ecology of this critically endangered species. In order to complete the final data collection phase and to promote public awareness of hawksbill turtle conservation, underwater photographic equipment is required. Over 200 hours of in-water data collection has resulted in the habituation of 8 turtles on a single insular reef. These turtles show little sign of alarm in the presence of divers and a unique opportunity exists to photographically document their natural behaviour. The photographic equipment is also required to develop turtle identikits, catalogue prey items, document foraging behaviour and to monitor their feeding habitats.
OBJECTIVES
• To quantify the nature and extent of foraging hawksbill turtle presence at the D’Arros/St. Joseph system.
• To describe the feeding ecology of hawksbill turtles at the D’Arros/St. Joseph system.
• To estimate the conservation status of hawksbill turtles at the St. Joseph system.
o Are there any current threats to this population?
o Does food availability affect population growth?
o Do recent coral bleaching events affect foraging hawksbills?
SPECIFIC CONSERVATION AIMS
TO PROMOTE THE PROTECTION AND CONSERVATION STATUS OF HAWKSBILL TURTLES
• To provide decision support for stakeholders involved with the conservation and management of foraging hawksbill populations
• To promote the ecological value of hawksbill turtles on the scientific arena
• To promote the economical value of hawksbill turtles through non-consumptive use
• To promote public awareness amongst consumers of hawksbill products