A select group of marine scientists joined Arksen on an expedition to Tonga in August for a region-first environmental DNA ( eDNA ) sampling mission, carrying out vital research into the make-up and behaviour of humpback whales during their annual breeding season.

Every year, the calm waters of Tonga’s Vava’u region are home to one of the most awe-inspiring events in nature as migrating whales arrive in large volumes to spend time nurturing their young in the protected areas.

The Arksen-operated expedition was led by National Geographic Explorer and scientist, Arzucan 'Zuzu' Askin , whose work with the Tonga Ocean Science Expedition alongside Keith Tuffley and Dr Sylvia Earle has been at the forefront of whale conservation in the Pacific. 

In support of Arksen’s charity, 10% for the Ocean , a number of bursary places were offered to scientists from around the world to join Zuzu and carry out the ground breaking scientific research to help protect and nurture these extraordinary animals.

First-time eDNA sampling

During a week-long adventure, the expedition team carried out cutting-edge eDNA sampling of the marine environment, collecting seawater samples which can be used to detect which cetaceans and marine vertebrates are present and assess the region’s genetic diversity.

New developments in technology are now enabling global scientists to use eDNA analysis to monitor and evaluate animals and ecosystems, rather than directly encountering, disturbing or distressing the wildlife they are trying to protect. 

All animals leave behind tiny traces of DNA in the marine environment through skin cells, faeces, mucus or other biological traces. Instead of relying on direct sightings or physical samples, eDNA sampling simply involves collecting seawater for laboratory analysis.

When filtered and analysed, the seawater samples reveal the unique genetic material and fragments of DNA that scientists can then cross-check with genetic reference databases to build a snapshot of which species are present, even if they are never seen.

As the DNA fragments degrade relatively quickly in seawater, detections often indicate recent presence, providing near real-time information, and the analysis also allows for simultaneous detection of multiple species.

As a result, studies have shown that water samples taken near whale habitats can reveal not only which species are present but also offer insights into population structure, migration patterns and biodiversity in surrounding ecosystems.

The study in Tonga is among the first in the region to examine genetic diversity in cetaceans using eDNA and the results of the work will be shared with Tongan authorities, global research databases and conservation partners. 

Holistic picture of the environment

Genetic diversity is nature’s insurance policy, enabling species to adapt to challenges such as disease, pollution, and climate change – and even apparently healthy-looking populations can be at risk if their genetic variation is too low. 

Alongside the eDNA data collection, the team also carried out some of the more established visual research techniques and audio sampling methods, with a view combining the findings to gaining a richer understanding of the overall marine biodiversity in the region.

The participating scientists were offered unique access to through the existing Tongan marine scientific research special interaction permits, which allowed them to get on the water and carry out their studies in full compliance with all local regulations.

The expedition identified a large number of humpback whale flukes and catalogued them for local, regional and global ID databases, and also documented the presence of ectoparasites, recording any lice, barnacles and cookie-cutter shark marks seen on the animals.

The sightings and behaviours were logged on a custom citizen-science app; whale song was recorded for behaviour, population and migration analysis and non-invasive microbiome samples were taken to assess diversity and health.

Combining the eDNA findings with the fluke photo-ID and acoustic records will enable researchers to develop a detailed picture of Tonga’s whale populations, their movements and their health, and use that knowledge to drive tangible protection measures.

The work hopes to help identify potential threats early, guiding conservation strategies before declines become visible – ensuring that this was more than a research trip, it was a step towards safeguarding one of the planet’s most spectacular marine gatherings.

Arksen will be running its Tonga scientific research expedition again in 2026, with spaces available both for research scientists and any individuals who would like to join in as citizen scientists to experience these incredible encounters and become part of the mission.