Ghost gear – what is it, and why do we care?
We know troublingly little about the true extent of lost fishing gear in our oceans. There is no estimated figure on the amount of ghost gear currently in the oceans; none that are considered accurate, at least. However, we estimate that fishing gear results in a loss of up to 30% of some fish populations and causes approximately 650,000 marine mammal deaths every year. The nylon used in gillnets is extremely strong & does not break down for hundreds, if not thousands, of years.

It’s important to realise that there is zero benefit to a fisher when they lose a net. This is central to our work; we collaborate with the fishing community, we don’t blame them.

To understand this a little better, let us explain the technical term for ‘ghost gear’, otherwise known as ALDFG: Abandoned, Lost or Discarded Fishing Gear.

Abandoned – gear that has become stuck at sea during deployment or at an irretrievable depth on the seafloor, and gets left behind;
Lost – when a deployed net or trap moves from its deployment location, so when the fishers return they cannot locate it;
Discarded – gear that is brought back on board but is found to be damaged. With no means of compensation for the material and no use for fishing, fishers may just throw it overboard.

ALDFG can be deadly to marine wildlife. Nets can envelop coral and snap off branches, break entire colonies or suffocate them completely. Small fish use the mass of nets as shelter in the vast ocean. This attracts larger predatory fish, which then become trapped within the nets. This in turn attracts much larger predators – at this point, you end up with sharks, rays and turtles becoming entangled, the lines cutting into their skin, stopping sharks from breathing and turtles from feeding. This most often has a sad end.

Researchers Kat and Sol observed this first hand in the Maldives. Kat discovered an Olive Ridley turtle caught in a mass of nets during a drone survey (the first time this has been done). The turtle received urgent veterinary care but still sadly succumbed to its injuries & died that night.

Why do we use drones?

In recent years, drones have become an increasingly popular and democratising tool in conservation and science in general. Until recently, aerial surveys would be conducted by plane or helicopter which are incredibly expensive, and therefore inaccessible to small conservation groups. Now, we’re able to cover kilometres of landscape at higher resolution than via satellite.

With drones, we cover wide survey areas in short periods of time, and require limited resources. The data provides us with information about biodiversity, habitat classification and encroachment of human activities. In terms of ghost gear, we are able to detect nets, lines and traps, and pinpoint their locations with extreme accuracy, producing GPS coordinates, which allows us to locate and retrieve them in-water, quickly and efficiently.

Drones also allow us to monitor wildlife to help shape more effective conservation strategies, and are far less invasive than other methods – meaning we can watch animals behaving as they would naturally, without disturbing them through our presence in the water. By using drones, we’ve been lucky enough to observe a pod of dolphins using a jellyfish as a ‘football’, a turtle snacking on a jellyfish (jellyfish don’t seem to be having a good time of it out on the reef!), schools of mobula interacting with eagle rays and reef sharks hunting together.

This is where our project comes in…

Aerial Recon and Recovery Initiative, or ARRI, is a project dedicated to the study of abandoned, lost, and discarded fishing gear (ALDFG) and its impacts on marine ecosystems.

We use aerial surveying via drone, coupled with action by local recovery and recycling teams, marine conservation organisations and dive centres, to restore coastal marine environments. We are extremely passionate about ocean conservation, cultivating relationships with local communities and researchers, and implementing long-lasting locally-managed solutions.

The ARRI Team: Our team consists of conservation ecologist and PhD Candidate Tania Kanchanarak, marine and shark biologist Kat Mason M.Sc., and conservation technologist Sol Milne, PhD. We are ecologists focused on studying Thailand’s marine environment using innovative technologies, and developing capacity to protect it long-term.

With support from Experiment Foundation, we spent 2.5 months of 2023 on Koh Phangan, Thailand carrying out our initial ALDFG surveys. It became apparent early on that the team were justified in their hypothesis that the coastlines were heavily impacted – over 200 pieces of gear were found around just the one island. We also spent a good amount of time SCUBA-diving, snorkelling and kayaking the coastline, and whilst we were saddened to see the state of many of the reefs, we were also surprised by just how well some of the corals and fish communities were doing.