Our Research Methods

From Data to Impact: Understanding Our Research Methods

At Gili Shark Conservation, we  teach a range of research methods to effectively gather the data required to support the goals in shark, turtle, and coral conservation of NGO Gil Matra Bersama. Each method is important for us to protect and save these important marine animals.  As a member of our research team, you will receive thorough training in these methods, which will enable you to actively contribute to our conservation work.  We are committed to giving you the skills and knowledge you need to make a real difference while you’re staying with us.

* Please know that the research methods Manta Tow, Land Time-Lapses and Underwater Time-Lapses are only being used for specific projects and not all year round.

Seagrass Restoration
Roving Survey Dives
Photo ID
Coral Health Index Surveys
Coral Watch Survey
Manta Tow Surveys
Citizen Science Data Collection
Reef Check
Coral Restoration
RUV (Remoted Underwater Video Surveillance)
PADI Scientific Diver Course Specialty

Roving Diver Fish Surveys

This method forms the basis of our PADI Scientific Diver Speciality Course. Divers swim through a dive site and record target fish species and their size in 10cm increments.  These surveys allow us to quantify the target species’ abundance and biodiversity.  This survey is an excellent introduction to scientific research methods and is our method of choice when there is a strong current.

Fish Belt Transect Research Method - Gili Shark Conservation

fish belt transects

This method involves a pair of divers swimming on either side of a transect and recording target fish species and their size in 10cm increments. Typically, divers sample 2.5m on either side of a 70m transect and 5m up into the water column, resulting in a sampling area of 1,750m3. These surveys allow you to quantify the target species’ abundance, density, biomass, and biodiversity.

Coral Health Index research method used by Gili Shark Conservation

Coral Health Index Surveys

Coral Health Index surveys were developed to ensure a standardised assessment of Indonesian coral reef health.  This is the method employed by the local marine park authority of the Gili Islands, whom we assist with these surveys.  There are two components, benthic and fish.

During the benthic survey, a 50m transect deployed, and a quadrat with a minimum area of 2552cm2 is placed at 1m to the left of the transect line (closest to the shore) and a photograph taken.  The quadrat is then repositioned at 2m on the right-hand side of the transect.  The survey continues with alternating quadrats on either side of the transect until 50 photographs have been collected.  These photographs are then analysed using CPCe software to determine various benthic species’ abundance, density and biodiversity.

During the fish survey, a 70m transect is deployed, and a survey is conducted as per the fish belt transect method described above.  These surveys allow you to quantify the target species’ abundance, density, biomass, and biodiversity.

Coral Health Watch Survey method used by Gili Shark Conservation to access the health of the coral reefs

Coral Watch Surveys

CoralWatch is a not-for-profit citizen science program based at The University of Queensland, working with volunteers worldwide to increase understanding of coral reefs, coral bleaching and climate change.

We use the Coral Health Chart, developed by CoralWatch in 2002, to conduct surveys.  This chart standardises changes in coral colours and provides a simple way for people to quantify coral health.

On the survey, we hold the chart next to a coral and record the lightest and darkest colouration in addition to recording the depth and coral lifeform.  We then upload this data to CoralWatch global database.

invertebrate belt transects​ by Gili Shark Conservation

Invertebrate Belt Transects

This method involves a pair of divers swimming on either side of a transect and recording target invertebrate species and specific reef features.  Typically, divers sample 2.5m on either side of a 50m transect, resulting in a sampling area of 250m2.  These surveys allow you to quantify the target species’ abundance, density, and biodiversity.

Turtle Identification Program around the Gili islands in Indonesia

Photo ID of Sharks and Turtles

Sharks and turtles have unique individual markings that allow them to be identified as individuals using the non-invasive photo identification method.  For sharks, photographs are taken of the left and ride sides of the body, and for turtles, photographs are taken of both sides of the face.  In addition, data is collected on location, depth, gender and size.  Photos are then analysed using i3s software, with results added to our database that allows us to track the movement of individuals around the Gili Islands.

Coral restoration by Gili Shark Conservation

coral restoration

Our coral restoration research project aims to restore reefs damaged by destructive fishing practices, coral bleaching, disease, and earthquakes to their original condition. Within our coral nursery, we grow corals using various techniques to determine the most effective methods and species for the Gili Islands. Once large enough, these coral fragments are outplanted onto the reef. Our work contributes to advancing coral restoration efforts, promoting knowledge sharing, and fostering sustainable practices for the long-term health of the marine ecosystem in the Gili Islands.


Photogrammetry is a technique to obtain reliable data on objects in an environment by creating 2D maps and 3D models.  The process involves taking overlapping photographs of an area which are then merged to form a larger picture.  We utilise photogrammetry to monitor our coral restoration structures, using these images to map growth and survival rate.

Seagrass restoration around the Gili islands in Indonesia

seagrass-watch surveys

Globally, Seagrass-Watch is one of the largest long-term seagrass observing programmes.  Utilising a variety of their established assessment methods, including belt transects and quadrats, we monitor the health status of seagrass beds around Gili Air and determine the effectiveness of our seagrass restoration project.

Baited Remote Underwater Video by Gili Shark Conservation

Remote Underwater Video Surveillance

The research method known as Remote Underwater Video (RUV) surveillance is a valuable technique used to study marine life and habitats. It involves deploying a remotely operated camera system into the underwater environment to capture high-resolution video footage. This method allows us to observe and document marine organisms and their behavior’s without directly disturbing them. We also utilise this footage to record our indicator species, which provide data on coral reef health and fishing practices.  

Timelapse drone project Gili Air by Gili Shark Conservation

land time lapses

Using drone footage, we observe changes in the coastal environment around Gili Air. This allows us to monitor coastal erosion and changes in the extent of coral reefs and seagrass beds around the island. These images aid us in focusing our restoration and research efforts.

Dive against debris by Gili Shark Conservation

Dive Against Debris

Dive Against Debris surveys are a PADI Aware Foundation initiative that allows divers to collect critical marine pollution data.  During these dives, underwater trash is collected within a specified dive site.  After the dive, this trash is sorted into categories and the data is submitted to the PADI Aware Foundation.

Citizen Science Data Collection Program on Gili Air by Gili Shark Conservation

citizen science data collection

Involving the local community is essential to our research and allows everyone living or visiting the Gili Islands to have a positive environmental impact. Through our Unite Gili and photo ID projects, members of the public can submit valuable data which aids us in reaching our scientific goals.

Manta Tow surveys

 Manta Tow Surveys are used to provide a general description of large areas of reef and to gauge broad changes in abundance and distribution of organisms on coral reefs. The advantage of manta tow over other survey techniques is that it enables large areas of reefs to be surveyed quickly and with minimal equipment. We are only using Manta Tow Surveys if we need to analyze if a certain area is suitable for our coral restoration work.