Methodologies for Tracking Sea Turtle Migration Trends

Methodologies for Tracking Sea Turtle Migration Trends

There are a few standard methods that are used world wide for carrying out investigation and research into sea turtle migration patterns. The traditional method of tracking the under sea movement of turtles is manual “Tagging”. The turtles when they come to nest or are foraging near the coast are tagged on their flippers. The tags are coded and since this activity is shared by a network of integrated government and non governmental conservation organizations worldwide, the information is exchanged and migration routes between various foraging and nesting areas plotted. In addition, new technologies of DNA mapping and satellite tracking are beginning to answer questions about behavior and migration. In the following sections, these new technologies get discussed in detail:

1. How Satellite Tracking Works: State of the Art Research

The technology of satellite telemetry has advanced to the stage of allowing researchers to track turtles in the open ocean after attaching Sony Walkman-sized transmitters to the backs of adult or immature sea turtles. The transmitters send signals full of information to an orbiting satellite each time the turtle surfaces for air. The satellite re-transmits the data to a receiving station on earth, which researchers can access through their computer and modem. After 8-10 months, the transmitters quit working and fall safely off the turtle.

1. Tortuguero Sea Turtle Tracking Project

In late September 2002, the Caribbean Conservation Corporation (CCC) attached satellite transmitters to the shell of a green sea turtle named “Miss Junie 2”, after she nested on the beach at Tortuguero, Costa Rica. After deploying the transmitters, the turtle was immediately released back into the wild to carry on with their normal behavior Using state-of-the-art satellite tracking technology. CCC and other researchers are now monitoring the movements of these and other turtles. Through CCC’s Turtle Migration-Tracking Education Program, the public is invited to watch along on the Internet as we learn more about these amazing animals.

2. Florida Juvenile Green Turtle Tracking Project

Along the coast of Florida in the U.S.A, an extremely successful project of satellite tracking has been carried out on the sea turtle named “Wallace”. Wallace was originally captured in 1996 in the Indian River Lagoon and has been recapped 3 times since. Wallace has remained in the same general area, but because the barrier island is so narrow and the accuracy of the hits are not exact, researchers have difficulty in telling if she is inside or outside.

2. Reading the Genetic Code: Use of DNA Mapping for Tracking Sea Turtle Migration Trends

DNA in a cell nucleus is from both mother and father, but the DNA in cells mitochondria - the bodies that produce the cells energy – is passed directly from female to offspring. That is the reason why mitochondrial DNA (mtDNA) is the preferred DNA marker used to mostly to find out about the fidelity of the turtles to their nesting and foraging sites. If female turtles are returning to their natal beaches to nest, the turtles on each beach would have similar and distinctive mitochondrial DNA. For the most part, they do.

In recent years, genetic markers have provided a valuable tool for elucidating the distribution of migratory sea turtle populations. Genetic tags have been used to identify the sources for mixed populations sampled away from breeding areas. In most species of sea turtles, females return to nest in the vicinity of their natal beach. The high degree of site fidelity on the part of the nesting females results in genetically discrete populations that are distinct demographic (and management) units. When turtles leave the breeding areas, however, reproductive populations may become mixed on foraging grounds, and the distinctions among management units are obscured

1. DNA Mapping of Green Turtles in Inagua Island, Bahamas

The turquoise and emerald shallows surrounding the small Bahamian Island of Great Inagua are feeding grounds for juvenile green turtles. Here University of Florida biologists Karen Bjorndal and Alan Bolten are using DNA to match the turtles with their native beaches and learn their migration patterns. The mtDNA of green turtle hatchlings is being collected. The Inagua study shows that greens born in Florida, Costa Rica, Suriname, and Venezuela’s Isla Aves are coming here to feed. The scientists are confident that they now have the mtDNA patterns of most of the major green turtle rookeries in the Atlantic and now they would be able to tell where these juveniles come from based on genetics and would not have to tag 10,000 turtles and wait to catch one.

2. Transatlantic Developmental Migrations of Loggerhead Sea Turtles Demonstrated by mtDNA Sequence Analysis

Molecular markers based on mtDNA control region sequences were used to test the hypothesis that juvenile loggerhead sea turtles in pelagic habitats of eastern Atlantic are derived from nesting populations in the western Atlantic. Scientists compared mtDNA haplotypes from 131 pelagic juvenile turtles (79 from the Azores and 52 from Madeira) to mtDNA haplotypes observed in major nesting colonies of the Atlantic Ocean and Mediterranean Sea. A subset of 121 pelagic samples (92%) contained haplotypes that match mtDNA sequences observed in nesting colonies. Maximum likelihood analysis estimate that 100% of these pelagic juveniles are from the nesting populations in south eastern United States and adjacent Yucatan Peninsula, Mexico. The link between West Atlantic nesting colonies and east Atlantic feeding grounds provides a more complete scientific basis for assessing the impact of sub adult mortality in oceanic fisheries.

Tracking Migration Trends of Nesting Green Turtles on the Hawksbay/Sandspit Beaches – The Present Status

The two main research organizations undertaking sea turtle conservation activities in the project area – namely, the Sindh Wildlife Department and the World Wildlife Fund Pakistan have for some time been involved in projects and activities aimed at investigating the migration trends and behaviors of nesting green turtles in the Hawksbay/Sandspit area. Following are discussed the details of their work.

3. Investigating Green Turtle Migration Trends by Satellite Tracking – WWF Pakistan

In the year 2001, WWF-Pakistan had initiated a collaborative research and conservation program with the Environment Research and Wildlife Agency (ERWDA) on mangroves and marine turtles. ERWDA provided WWF Pakistan with two satellite transmitters for installation on two of the nesting green turtles on the Hawksbay/Sandspit beaches. Two experts from ERWDA, namely, Dr.John Hoolihan and Dr.Himansu Das conducted satellite tagging on two of the nesting marine turtles at Sandspit, Karachi coast, in the night of August 1^st and 2^nd, 2001.

F
Map – 1

or ensuring accurate information based on satellite tracking, the following procedure was adopted. Two green turtles were captured after they had completed nesting on the Sandspit beach. The location of the capture of the green turtles was marked with the help of Global Positioning System. For identification purposes, the turtles were named as Chandni I & Chandni II. The captured turtles were later transported to the WWF’s Wetland Centre and put into a wooden box with their heads covered by wet towels.

T
Map – 2

he first scute of the dorsal side of each of the green turtles was selected for installation of the satellite transmitter. The scutes were rubbed with the help of sandpaper to make the surface rough so that adhesive can work easily on it.

Elastomer mixture was rubbed on the back of the device and then it was placed on the scute of the carapace. The device was placed in such a position that the antenna pointed towards the tail of the turtle. The drying out of Elastomer took about an hour and thirty minutes. A second adhesive i.e. marine polyester laminator resin mixed with a catalyst was applied on the devise by using 1.5 “ * 1.2” strip on either side of the device. The transmitter was then covered with different layers of fiber glass strips. Before covering, the visiting cards of ERWDA and WWF Pakistan were put on the device. A double coating of resins was applied on the device. Two salt water switches were present at the anterior side and masking was removed from them to make them operational.

The green turtles were then carried to the same place from where they were captured. Before releasing them in the sea, a tag was attached on each front flipper. Location data was later received through ARGOS, a satellite based system that tracks sea turtles when they surface for air. The data was transmitted to the station, then to the user. With the help of GIS Programming, the turtle migration pattern was located. (See Table1/2 for log sheets of Chandni I& II – and Map 1&2 for Turtle Migration Pattern)
Table# 1 - Log Sheet of Chandni I

(Transmitter No. 14812 – Tag No. W3090/Left &W9029/Right)

Date	Time	No. of Eggs
01-08-2001	8:00 pm	103
16-08-2001	10:00 pm	96
28-08-2001	22:45 pm	Visit (no eggs)
29-08-2001	22:45 pm	103

Table# 2 - Log Sheet of Chandni II

(Transmitter No. 14810 – Tag No. W9034/Left &W9035/Right)

Date	Time	No. of Eggs
02-08-2001	09:05 pm	100
17-08-2001	09:45 pm	76
31-08-2001	09:10 pm	Visit (no eggs)

4. Documenting Green Turtle Migration Trends – Sindh Wildlife Department

According to the Sindh Wildlife Department figures, from October 1979 to December 1997, 1,531,980 eggs from 17,702 nests were transplanted to enclosures (three # enclosures, each having a capacity of 300 nests) to protect them from predators. Of these, 1,453,966 were green turtle eggs from 17,702 nests and 78, 014 were olive ridley eggs from 654 nests (see Chart1). A total of 3,91,556 hatchlings were released to the sea. Out of these, 3,70,414 were green turtle hatchlings and 21,142 were olive ridley hatchlings. In addition, 88,108 hatchlings were collected from from outside the enclosures and were released to the sea. In total, 4,79,664 hatchlings were released to the sea.

However, only about 5000 turtles have been tagged so far. Adults have been tagged with Monel Tags (size 19, style 49) on the trailing edge of both front flippers, as these areas are less frequently damaged. Tags have been applied after egg laying following methods by Balasingham (1966) and Bustard (1972). Tag returns have been received from local areas and a few records of long distance migrations have also been reported

Preliminary Feasibility for using DNA Mapping for determining Migration Patterns of Green Turtles nesting in the Sandspit/Hawksbay beaches

Discussed below are the various relevant issues related to working out the preliminary feasibility for using DNA mapping for determining migration patterns of green turtles nesting in the Sandspit/Hawksbay beaches

5. The Technology

When we assess the results of the various methodologies used to track sea turtle migration trends, then it becomes clear that manual tagging is an extremely tedious process while the risk factor associated with satellite tracking of sea turtles is significant with the inherent chances of the sea turtles getting killed or the transmitter getting unhooked. Where DNA mapping scores a clear advantage is that it reduces the workload and cuts down on the risk factor. However, a certain level of technological advancement is required to make effective use of this technology.

As has been mentioned earlier, greater success of scientific research, when it comes to sea turtles, lies in an integrated approach. This is because sea turtles spend most of their lives under the sea, moving between their foraging and breeding grounds. It is therefore essential to link up the research work with as many agencies and organizations engaged in sea turtle conservation efforts as possible, the world over. It is only then that effective conservation plans are developed that properly addresses the wide geographical range of sea turtle movement, spread over different oceans and continents.
In order to achieve harmony and cohesion in scientific research between different countries, a certain level of similarity in approaches and methods is required. Manual tagging is a simple process requiring minimum level of technological input. Use of satellite tracking is gaining ground with research organizations in the less developed countries making greater use of this technology to track the movements of their sea turtle populations. However, DNA mapping is a concept that remains mostly unutilized in countries such as Pakistan, where the level of technological advancement is not in anyway comparable to the western and developed world.
However, where Pakistan is fortunate is that certain centers of excellence in scientific and medical research have developed through the contributions and efforts of the private/non governmental sector and local philanthropists that provide state of the art services, comparable to any of their counterparts in the developed world. These include among others, the Aga Khan University Hospital, Karachi and the Hussain Ebrahim Jamal (HEJ) Research Institute, Karachi. The Aga Khan University Hospital provides state of the art services in DNA profiling, which though till now have only been extended to humans. Therefore, a financial estimation for providing the required facilities for DNA profiling of sea turtles would need to worked out. However, it is not just a matter of finding a facility where DNA profiles can be prepared, a substantial effort is required to build the relevant capacity in the organizations already involved in sea turtle conservation efforts in the project area to so that they can make effective use of this technological option. At present, this desirable level scientific development is found lacking.

6. The Institutions

It is logical that the Sindh Wildlife Department and the World Wildlife Fund, Pakistan be identified as the key organizations to lead the work in exploring the potential of initiating the process of DNA mapping of the sea turtles visiting the Sandspit/Hawksbay beaches. However, in order to extend the scope of this work and facilitate the requirements of applied scientific research, it is suggested that a scientific institute be identified and its capacity built to participate in this process. For this purpose, the Department of Molecular Genetics at the University of Karachi is being identified.

Linkages would also need to be established with research organizations in other relevant countries that are undertaking similar research in order to match and correlate data for understanding migration trends and develop integrated strategies and projects for sea turtle conservation.

7. Geographical Scope of Research

In order to identify countries and organizations with whom collaborative mechanisms for scientific research can be forge, it is essential first to investigate possible migratory routes of the turtles visiting the Sandspit/Hawksbay beaches. As has been mentioned in the earlier sections, gyres and oceanic currents and wave patterns play a significant role in determining the sea turtle migration trends. Sea turtle hatchlings enter the gyre and remain there for years. Wave/current patterns also play a significant role in determining their movement patterns.

In the following sections, baseline assessment is made of the seawater circulation patterns and gyre/currents movement along the Karachi coast.

1. Seawater Circulation Patterns along the Coast of Karachi

Information about the seawater circulation patterns and oceanic current movements along the Karachi coast would be helpful in identifying possible movement and migration patterns of sea turtles visiting the Sandspit/Hawksbay beaches. The sea water circulation pattern along the coast of Karachi can be grouped into three types:

• 
  Clockwise Circulation
  
• 
  Anti-Clockwise Circulation
  
• 
  Mixed Circulation
  

The dominant direction of the seawater flow in the coastal waters of Karachi is clockwise i.e. the major flux of seawater from offshore area enters the coastal waters of Karachi at the western coast area from the southwest. This water then moves along the coast towards the east and then in southeast direction forming a big gyre. This pattern is common mostly during mid April to September period as a consequence of the south west monsoon winds blowing strongly during this period.

The seawater circulation reverses its direction in response to the direction of the prevailing northeast monsoon wind direction. The anti-clockwise circulation of seawater is mostly restricted to the December-January period - the period of the northeast monsoon winds in this area. The seawater from the near shore and offshore Indus Delta enters the coastal waters of Karachi from the southeast and moves along the coast towards northeast, westward and then at the west coast of Karachi, it moves in the south east direction to the offshore area.
There are transition periods between the southwest and northeast monsoons period when the direction of the wind changes frequently. This also results in the complex circulation pattern along the coast with many clockwise and anti-clockwise gyres which persist for short periods only. The dominant direction of the surface circulation during the transition periods depends mostly on the persistent direction of the prevailing winds. Although the seawater circulation patterns during the transition periods (i.e. February-March, October-November) are mixed but there is an identifiable component of anti-clockwise direction during March-April, October-November and clockwise during February. The detailed directions of the seawater circulation pattern along the near shore areas of the coastal belt during the transition periods are not yet mapped and documented.

2. Seawater Currents

The predominant direction and speed of the seawater currents for the South Eastern Karachi coast is given in Table 3. The speed of the current is generally low, about ½ knots. The speed increases up to 1 knot during SW monsoon. The direction of the set is directly related with the prevailing wind system. The set is generally easterly in the SW monsoon and westerly in the NE monsoon. The slight difference in direction in the Western and Eastern part of the Karachi coast is due to circulatory pattern of the current around gyres that are usually formed at the center of the sea. There is a clockwise gyre during SW monsoon and an anti-clockwise gyre during NE monsoon.
Table# 3 – Predominant direction and speed of sea surface currents off South Eastern Karachi Coast

Seasons	Direction of Set (Degrees)	Speed (Knots)	Constancy in Direction (%)
North East Monsoon (Dec-Jan)	W	½	Greater than 33
Pre-Monsoon (Feb-May)	E-ENE	½	Greater then 33
SW Monsoon (June-Sep)	E-ENE to ESE	½-1	33-36
Post SW Monsoon (Oct-Nov)	E	1/2	Greater then 33

8. Potential Migration Routes

Based on the available data and research on documented sea turtle movements, prevailing seawater circulation and oceanic current movements, it can be suggested that two possible migration routes for the sea turtles visiting the Sandspit/Hawksbay beaches could be studied and investigated using the DNA mapping technique:

1. Migration Route#1

It is possible that the movement of the sea turtles, particularly in the earlier phase of their lives when they are driven by the gyre movement predominant along the coast, is restricted to the Northern Arabian Sea, moving back and forth between turtle nesting/foraging grounds in the vicinity of Oman and Gujrat, India.

2. Migration Route#2

It is possible that the movement of the sea turtles, when they are driven by the oceanic currents, in particular, the Somali current, is restricted between the coasts of East Africa and Far Eastern countries.

Collaborative Linkages

It is therefore important that contacts are established with countries like India, Oman, Malaysia and selected countries in East Africa to explore the possibilities of joint or coordinated research.

A need does exist for utilizing the option of DNA mapping for studying the sea turtle migration trends. A positive feasibility also exists for exploring in detail the potential for initiating such a process. However, the financial, technical and institutional requirements of this option and long term strategies, plans ad projects would need to be assessed and evaluated in detail prior to implementation.

_________________

TABLE OF CONTENTS

Objective of the Study 1

Study Methodology 1

Sea Turtles-Distribution and Habitat 1

1.1. Green Turtles – Distribution and Habitat 2

2. Movement Patterns 3

Understanding Sea Turtle Migration Trends 4

Methodologies for Tracking Sea Turtle Migration Trends 6

2.1. How Satellite Tracking Works: State of the Art Research 7

2.1.1. Tortuguero Sea Turtle Tracking Project 9

2.1.2. Florida Juvenile Green Turtle Tracking Project 10

2.2. Reading the Genetic Code: Use of DNA Mapping for Tracking Sea Turtle Migration Trends 10

DNA in a cell nucleus is from both mother and father, but the DNA in cells mitochondria - the bodies that produce the cells energy – is passed directly from female to offspring. That is the reason why mitochondrial DNA (mtDNA) is the preferred DNA marker used to mostly to find out about the fidelity of the turtles to their nesting and foraging sites. If female turtles are returning to their natal beaches to nest, the turtles on each beach would have similar and distinctive mitochondrial DNA. For the most part, they do. 10

2.2.1. DNA Mapping of Green Turtles in Inagua Island, Bahamas 11

2.2.2. Transatlantic Developmental Migrations of Loggerhead Sea Turtles Demonstrated by mtDNA Sequence Analysis 11

Tracking Migration Trends of Nesting Green Turtles on the Hawksbay/Sandspit Beaches – The Present Status 12

2.3. Investigating Green Turtle Migration Trends by Satellite Tracking – WWF Pakistan 12

2.4. Documenting Green Turtle Migration Trends – Sindh Wildlife Department 15

Preliminary Feasibility for using DNA Mapping for determining Migration Patterns of Green Turtles nesting in the Sandspit/Hawksbay beaches 16

2.5. The Technology 16

2.6. The Institutions 18

2.7. Geographical Scope of Research 18

2.7.1. Seawater Circulation Patterns along the Coast of Karachi 19

2.7.2. Seawater Currents 20

2.8. Potential Migration Routes 21

2.8.1. Migration Route#1 21

2.8.2. Migration Route#2 22

Collaborative Linkages 22

It is therefore important that contacts are established with countries like India, Oman, Malaysia and selected countries in East Africa to explore the possibilities of joint or coordinated research. 22

LIST OF TABLES
Table # 1 — Log Sheet of Chandni I 12

Table # 2 — Log Sheet of Chandni II 12

Table # 3 — Predominant direction and speed of sea surface currents off South Eastern Karachi Coast 17

LIST OF MAPS
Map # 1 — Movement of Chandani I 11

Map # 2 — Movement of Chandani II 11

Preliminary Feasibility Study for using DNA Mapping for determining Migration

Patterns of Green Turtles Nesting

in the Sandspit/Hawksbay Beaches

(Project — Helping the Turtles Survive)
Submitted by:
Shehri—CBE

(December 2004)

A GEF/SGP Project of UNDP Pakistan

Preliminary Feasibility Study for using DNA Mapping for determining Migration Patterns of Green Turtles Nesting in the Sandspit/Hawksbay Beaches

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