A simple innovation using coconuts and inexpensive satellite trackers has proven successful in collecting valuable oceanographic data on the Great Barrier Reef. The low-cost, biodegradable drifters offer a practical alternative to conventional ocean-tracking equipment, with potential applications well beyond reef research.

Deployed during the December 2025 coral spawning event, five coconut drifters travelled a combined 1,355 kilometres over 27 days, transmitting 2,823 GPS positions as they moved through the waters off Cairns. The experiment, coordinated by the Reef & Rainforest Research Centre in collaboration with research, conservation, tourism, and Traditional Owner partners, was designed to provide real-world observations of ocean currents for testing a sophisticated regional ocean model.

The results, now published in the international scientific journal Oceanography, demonstrate how simple, inexpensive materials can support sophisticated oceanographic research. Building on this success, the research team is preparing another series of deployments during the 2026 coral spawning season.

Understanding how reefs are connected

Ocean currents play a fundamental role in the health and resilience of the Great Barrier Reef, transporting coral larvae, fish larvae, and other marine organisms between reefs. Understanding these connections helps scientists investigate how populations disperse, how damaged reefs might recover, and where restoration efforts could be most effective.

Researchers at the University of Western Australia have developed a high-resolution Regional Ocean Model for the central Great Barrier Reef (GBR ROMS), commissioned by the Reef & Rainforest Research Centre. The model simulates water movement through the complex reef environment, providing a foundation for investigating how marine organisms may disperse between reefs. However, sophisticated computer models need to be tested against real-world observations. Researchers needed an inexpensive, practical way to track surface currents and compare actual water movements with the model’s predictions.

Their solution was surprisingly simple: coconuts.

Nature’s ocean drifters

Coconuts are naturally buoyant, durable, biodegradable, and capable of travelling considerable distances across oceans. Recognising these advantages, the research team developed a simple design using locally collected coconuts fitted with commercially available SPOT Trace satellite trackers. Each coconut was hollowed to accommodate a tracker, sealed with paraffin wax to protect the electronics from seawater, and fitted with recycled metal weights to ensure the tracker remained facing upwards.

Each drifter cost approximately A$276 to construct and activate, including the satellite tracker, which accounted for most of the expense. The trackers could also be recovered and reused, substantially reducing the cost of subsequent deployments. The biodegradable coconut housings also offer an alternative to synthetic flotation materials, reducing the risk of persistent plastic pollution.

On 10 December 2025, five coconut drifters were deployed at hourly intervals from the Reef Magic pontoon at Moore Reef, east of Cairns. Gunggandji Land and Sea Rangers attended the deployment, while a specially developed online tracking platform allowed project partners to follow the coconuts’ journeys in near real time.

All five devices began transmitting immediately, and their subsequent movements revealed the complexity of surface currents in this part of the Great Barrier Reef. Two travelled north before returning towards their deployment area, while another two initially headed south towards the Frankland Islands before eventually moving north again. The fifth washed ashore on Fitzroy Island after just two and a half days.

The longest-travelling coconut covered more than 592 kilometres over 27 days, eventually becoming entangled in mangroves near the Bloomfield River. Four of the five devices were successfully recovered through the combined efforts of project partners, including Gunggandji Land and Sea Rangers, and their satellite trackers were retrieved for reuse.

Importantly, the coconut drifters are not intended to represent the movements of coral spawn and larvae; instead they provide real-world evidence of surface water movements that can then be used to verify GBR ROMS predictions during the window of coral larval competency. Once validated, the model can be used with specialised particle-tracking software to investigate the potential dispersal of coral larvae, fish larvae, crown-of-thorns starfish larvae, and other marine organisms, helping inform future reef management and restoration strategies.

Building on the success

Following the successful pilot, the research team assembled approximately ten additional coconut drifters for deployment during the October and November 2026 coral spawning events. The new devices were constructed at the Reef Cooperative Reef Star Factory in Portsmith, Cairns, with Gunggandji Land and Sea Rangers and Junior Rangers participating in their construction.

On 30 October, five coconut drifters were successfully deployed by kayak near Low Isles, coinciding with reports of coral spawning elsewhere on the Great Barrier Reef. All five devices began transmitting, providing real-world observations of surface water movements during this important period for reef reproduction and connectivity.

A custom-built, live tracking platform allows researchers and the public to follow the drifters’ journeys as they unfold. Further deployment activities are planned for November, while Indigenous ranger groups may assist with recovering the devices depending on where they eventually wash ashore.

The continued involvement of Traditional Owners and Junior Rangers also demonstrates the potential for this accessible technology to support locally led scientific investigations and practical learning opportunities.

Affordable ocean science with international potential

Although developed for the Great Barrier Reef, the coconut drifters have considerable potential throughout the tropical Indo-Pacific, including Polynesia, Micronesia, Melanesia, and Southeast Asia. In regions where research funding and access to specialised scientific equipment may be limited, inexpensive ocean-tracking technology could provide new opportunities to investigate coastal currents, marine connectivity, and the movement of floating materials.

The approach could also support community-led research and education. Interest has already emerged among Reef Guardian schools and Junior Indigenous Ranger groups in using coconut drifters to investigate water movement around their local reefs. The original dataset is also being used in postgraduate ocean modelling courses at the University of Western Australia.

The project brings together expertise and resources from the Reef & Rainforest Research Centre, the University of Western Australia, Resilient Reefs Foundation, GBR Biology, GFD Ltd, and the Gunggandji Aboriginal Corporation. Through shared scientific expertise, local knowledge, equipment, and logistical support, the partners have demonstrated how valuable oceanographic data can be collected at relatively low cost.

With further development, coconut drifters could become an accessible research tool for scientists, schools, and coastal communities around the world, helping expand our understanding of ocean processes without the need for expensive, specialised equipment.

Read the published research

Long, S., D. Stanley, I. Janekovic, C. Bee, R. Donnelly, E.E. Fisher, and S. Morris. 2026. Let’s go nuts! Development and field testing of low-cost biodegradable coconut drifters for surface current tracking and regional ocean model validation. Oceanography 39(3):26–31.