A critically endangered breed of turtle has seen an eight-fold increase in numbers according to new research from the University of East Anglia.
Above: A hawksbill turtle on Cousin Island. Photo by James Hardcastle.
The already endangered hawksbill turtle (Eretmochelys imbricata) was listed critically endangered in 1996 by the International Union for Conservation of Nature (IUCN), largely due to the international trade of tortoise shell as a decorative material – an activity which was banned in the same year.
New findings published online by the journal Endangered Species Research show that numbers of nesting females in the Cousin Island Special Reserve in the Seychelles have increased eight-fold since the early 1970s. The increase is directly attributed to an ongoing turtle conservation programme on the island.
The study has been carried out by former MSc student Zoё Allen, Prof Alistair Grant and Dr Diana Bell from the University of East Anglia, in collaboration with researchers from conservation organisation Nature Seychelles – Nirmal Shah and Gilles-David Derand.
The Seychelles are home to the largest remaining population of hawksbill turtles within the western Indian Ocean. Cousin Island is one of the most important nesting grounds for the hawksbill and has one of the longest running turtle monitoring programmes, which dates back to 1970.
The new research shows an estimated peak of 256 turtles nesting on the island each season between 2007-2008, compared with just 23 in 1973. In the early 1980s the number had risen to 28-30 turtles, and by 1994, an estimated 40-60 were breeding.
The latest data covers a 10-year period between 1999 and 2009 – during which time the population increased at an average rate of 16.5 turtles per season.
Turtle populations are notoriously difficult to census, relying on long-term monitoring of females at their nesting beaches. Females were individually tagged and nesting data derived from actual turtle sightings and evidence of nesting attempts, such as tracks on the beach.
Survey effort varied over the years, however the underlying trends over time are considered robust.
Dr Bell said: "The Seychelles are important for the hawkbill population and this study demonstrates the value of long-term monitoring programmes.”
Lead author Zoё Allen agrees that whilst this is a fantastic success story for the species, it does not necessarily mean that the hawksbill turtle will be taken off the critically endangered list any time soon.
She said: “This is a relatively small regional success, in an area that is well protected and in a country where legislation is generally well enforced and the local people understand the value of this species for tourism and the economy. This does not necessarily reflect world-wide population trends, however it is a very positive example of what can be achieved.”
Nirmal Shah, chief executive of Nature Seychelles, said: “These findings are a validation of the important work carried out on Cousin. It is long-awaited proof that conservation works even for long lived and critically endangered species like marine turtles.”
Read the full paper here
The already endangered hawksbill turtle (Eretmochelys imbricata) was listed critically endangered in 1996 by the International Union for Conservation of Nature (IUCN), largely due to the international trade of tortoise shell as a decorative material – an activity which was banned in the same year.
New findings published online by the journal Endangered Species Research show that numbers of nesting females in the Cousin Island Special Reserve in the Seychelles have increased eight-fold since the early 1970s. The increase is directly attributed to an ongoing turtle conservation programme on the island.
The study has been carried out by former MSc student Zoё Allen, Prof Alistair Grant and Dr Diana Bell from the University of East Anglia, in collaboration with researchers from conservation organisation Nature Seychelles – Nirmal Shah and Gilles-David Derand.
The Seychelles are home to the largest remaining population of hawksbill turtles within the western Indian Ocean. Cousin Island is one of the most important nesting grounds for the hawksbill and has one of the longest running turtle monitoring programmes, which dates back to 1970.
The new research shows an estimated peak of 256 turtles nesting on the island each season between 2007-2008, compared with just 23 in 1973. In the early 1980s the number had risen to 28-30 turtles, and by 1994, an estimated 40-60 were breeding.
The latest data covers a 10-year period between 1999 and 2009 – during which time the population increased at an average rate of 16.5 turtles per season.
Turtle populations are notoriously difficult to census, relying on long-term monitoring of females at their nesting beaches. Females were individually tagged and nesting data derived from actual turtle sightings and evidence of nesting attempts, such as tracks on the beach.
Survey effort varied over the years, however the underlying trends over time are considered robust.
Dr Bell said: "The Seychelles are important for the hawkbill population and this study demonstrates the value of long-term monitoring programmes.”
Lead author Zoё Allen agrees that whilst this is a fantastic success story for the species, it does not necessarily mean that the hawksbill turtle will be taken off the critically endangered list any time soon.
She said: “This is a relatively small regional success, in an area that is well protected and in a country where legislation is generally well enforced and the local people understand the value of this species for tourism and the economy. This does not necessarily reflect world-wide population trends, however it is a very positive example of what can be achieved.”
Nirmal Shah, chief executive of Nature Seychelles, said: “These findings are a validation of the important work carried out on Cousin. It is long-awaited proof that conservation works even for long lived and critically endangered species like marine turtles.”
Read the full paper here
