Tag Archives: Turtles

Seychelles – a great place to be a turtle!

while she lays, data are collected (Herve Chelle)

Turtle program on Cousin started in 1972 (Herve Chelle)

Last week I was on Cousin Island Special Reserve, with a group of visitors on a guided tour of the island. On the beach we watched as a hawksbill turtle made its short journey back to the sea from laying her eggs. Laborious on land, but effortless in the sea, the hawksbill turtle lays more than 100 eggs into a small pit dug in the sand.

The Seychelles in general and Cousin Island in particular is a great place to be a turtle. Every year around this time, hundreds of female hawksbill turtles will arrive on one of our beaches to nest. The archipelago provides key nesting and feeding areas for the critically endangered hawksbill and is home to the largest remaining population in the Western Indian Ocean. This population, sea turtle experts have said recently, is among the twelve healthiest sea turtle populations globally.

A report produced by IUCN (International Union for Conservation of Nature) Marine Turtle Specialist Group (MTSG) has revealed the most threatened and most healthiest of all sea turtles (there are 7 species) populations globally. It is the first comprehensive status assessment of all sea turtles. See this story here.

It shows that the hawksbill turtles populations in the Southwestern Indian Ocean (Seychelles, British and French Overseas Territories) and in Southeast Indian Ocean and Southwest Pacific Ocean (Australia) are the healthiest. But Hawksbill are threatened in the East Pacific Ocean, East Atlantic Ocean, Northeastern Indian Ocean, and West Pacific Ocean.

The report says that the most significant threats to sea turtles are fisheries bycatch, accidental catches of sea turtles by fishermen targeting other species, and the direct harvest of turtles or their eggs for food or turtle shell for commercial use. The healthiest populations are large and currently facing relatively low threats.

Hawksbill turtles were heavily exploited for many years in Seychelles, mainly for their shell. In 1994 a law that granted them complete protection was passed and harvesting was completely banned, although occasional poaching still occurs.

Turtle conservation is carried out on many islands. One of conservation’s success stories for the hawksbill turtle has been registered on Cousin Island, where a long-term monitoring programme started in 1972 is firmly established.

Baby hawksbills begin to come out

Happy New Year

We have good news here. The waiting period – approximately 60 days – is over and hatching of Hawksbill turtle eggs laid on the Cousin beach has began. Mary and Eric have had a busy time with turtle work. The work continues with the hatching. As reported earlier, apart from the regular monitoring program based on beach patrols carried out around the island to intercept and collect data on as many turtles as possible, Nature Seychelles – with technical assistance from Kelonia Marine Turtle Observatory in Reunion – this season introduced the use of data loggers to measure temperature in selected nests. Temperature inside the turtle nests is known to determine the sex ratio of hatchlings. Warmer temperatures produce more females and cooler temperatures give more males. This is an important area of study, as with rising global temperatures, it is important to understand the potential impacts of climate change on this critically endangered and thermally sensitive species.

When hatching occurs in the nests with data loggers (30 in total) Mary and Eric pick up and measure the weight and length of 30 of the hatchlings, as well as categorizing nest content to determine hatchling success.

weighing.jpg

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They are then put in basket such as the one below with a shadow to avoid dehydration.

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When the sample hatchlings have been measured  and weighed, they are released and head out to sea. The release is controlled to avoid the high level of predation by ghost crabs.

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It is impossible to tell the sex ratio of the hatchlings when they are this small. But from the data collected from the data loggers it is possible to determine the approximate sex ratio using existing and new temperature data. We will give you more information on how this pilot study evolves.

More on turtle work

Turtle laying her eggs

Hawksbill turtles go into some sort of trance when laying their eggs and mademoiselle here shows us how that looks like.

Eggs weighed and measured

While she is in this low state of awareness, her eggs are quickly counted and weighed.This is done by two people as it has to be done very quickly before she completes laying and starts covering the nest with sand. If she does complete her egg laying before the weighing and measuring is complete the eggs are quickly put back anyway.

data logger

This is the tail end of the data logger (and turtle :)) which is also currently being placed in the nest. Nature Seychelles is piloting this experiment with data loggers – with technical assistance from Kelonia – to gauge nest temperature. Data loggers record temperatures of nests throughout incubation. Sex determination in sea turtles is dependent on temperature, with a pivotal temperature in which equal numbers of males and females are produced. Temperatures above this pivotal number produce females and those below produce males. So data loggers help with sex ratio determination. The temperatures can also be used as indicators of the potential impact of  global warming on hawksbill turtles.

Photo ID anyone?

No two individuals, even identical twins, have identical sets of fingerprints. For this reason fingerprints offer a reliable means of identification. They have played a huge role in the area of forensics providing accurate identification of criminals.

As it turns out, marks and patterns on certain marine animals are akin to human fingerprints and are unique to each individual. These marks are being put to good use, not to catch the criminals of sea world, but as a means of identification to help in conservation.

On Thursday 12 November, the Marine Conservation Society Seychelles, in collaboration with the Kelonia Marine Turtle Observatory in Reunion and Ministry of Environment organised a talk on how this form of identification is being utilsed for whale sharks and turtles. The talk, “using images to conserve endangered marine life” was delivered by David Rowat, MCSS, who is working with whale sharks in Seychelles  and Claire Jean from Kelonia working with turtles. As in humans where fingerprints develop at the embryonic stage and do not change, all indications in these marine animals are that marks are usually permanent with little change occurring over time.

According to Claire, Kelonia uses underwater photos of marine turtles head profiles for indetification. Their methodology consists of analyzing scale numbers and shape of both right and left profiles. Photos of these profiles are taken for each turtle. A database has been created to keep these photos. The matching of the new data with those in the database allows one to determine whether or not each marine turtle has been seen previously. Thanks to the participation of scuba divers and marine photographers, photos can be collected throughout the year in various sites.

Claire says photo ID can be used as an alternative or complimentary monitoring method. But she noted that current monitoring methods that use capture-mark-recapture techniques, require physical application of tags. Photo ID on the other hand is non-intrusive, less costly and less stressful. It is particularly useful in places where marine turtles cannot be caught and tagged and helps in situations where tags are lost. It also targets all turtles unlike the capture method, which mostly targets females and juveniles. It can be used in all habitats either at sea or one beaches. What it cannot be used for is measuring other parameters such as growth.

For whale sharks, researchers use photographs of the skin patterning behind the gills of each shark and any scars to distinguish between individual animals. Cutting-edge software supports rapid identification using pattern recognition and photo management tools. See whaleshark.org  for more information. David Rowat said that using this method between 2001-2009, 447 individual sharks have been identified in Seychelles. Fifty percent were re-sightings.

Picture via whalesharks.org

Both these projects rely on the contribution of pictures from people, and pictures come via tourists, scuba divers and others, allowing for public participation. They are asked to take good high resolution photos without obstruction, such as sand on turtles.  Identification however is done by trained people.The talk ended with an offer from Kelonia to conduct training for organizations involved in turtle monitoring in Seychelles.

Posted on our website today: Turtle Poachers arrested in Seychelles

Two men have been arrested for possession of turtle meat and spearguns. The taking, selling or buying of turtles is illegal under the  Wild Animals and Birds Protection Act. Offences under this law carry a maximum fine of SR500,000.00 (about 36,000.00 USD) or a maximum term of two years imprisonment. Spearguns have been banned in Seychelles since the 70’s under Fisheries legislation and the Penal Code.

Read more… 

Picture of the Day: Break out!

 babyhawksbill

Sent in by Jovani Simeon, the Senior Warden on Cousin Island, this photo shows baby Hawksbill turtles coming out during the nesting season on Cousin. Nesting begins end of August and ends beginning March. 99% of all turtles that nest on Cousin are Hawksbill. We also get green turtles, but very few each year. The eggs of Hawksbill take roughly 58 days to incubate.