Indonesian scientists have developed a new method to detect walking sharks by testing seawater samples for environmental DNA (eDNA). This technique allows researchers to map species like the Indonesian speckled carpetshark without conducting nocturnal reef surveys, aiding conservation management in the Raja Ampat archipelago.
How does the new shark detection method work?
Researchers collect approximately three to five litres of seawater from a specific site to test for environmental DNA. This involves identifying tiny particles of genetic material, such as skin cells, mucus, or faeces, left behind by organisms in the water.
To identify these specific creatures, researchers at the National Research and Innovation Agency (BRIN) developed a novel genetic primer. According to researcher Danang Prabowo, this primer can pick up a gene unique to the walking shark genus even when it is present in relatively low concentrations.
Why is this discovery important for marine conservation?
Traditional monitoring is difficult because walking sharks are nocturnal and frequently hide in coral crevices. Edy Setyawan, a lead conservation scientist at Elasmobranch Institute Indonesia, said the method allows for detection during the daytime and helps confirm the presence of sharks before a survey begins.
The new process also improves safety for field teams. Setyawan noted that using seawater samples reduces the risk of researchers encountering other marine animals, such as stingrays and saltwater crocodiles, during nocturnal surveys.
Mochamad Iqbal Herwata Putra, a senior manager at Konservasi Indonesia, said the Indonesian speckled carpetshark performs an irreplaceable ecological function. He added that these sharks help balance the coral reef food web and can serve as indicators of marine resilience due to their ability to withstand higher temperatures.
What happens next for walking shark research?
The eDNA method is expected to be used for broader monitoring efforts across the region. Scientists plan to use the technique to detect and map walking shark species in other areas, including Papua New Guinea and the island of Halmahera, later in 2026.
Frequently Asked Questions
What is environmental DNA (eDNA)?
eDNA refers to tiny particles of genetic material, such as skin cells, mucus, or faeces, that living organisms leave behind in the water.
Why is it difficult to study walking sharks?
Walking sharks are nocturnal and tend to hide in coral crevices, which makes it difficult for scientists to map their distribution accurately through visual surveys.
How do walking sharks move?
Walking sharks use their pectoral and pelvic fins to “walk” along the sea floor.
How could molecular biology change the way we protect endangered marine life?
