Medical gauze can identify shark species following attacks

Scientists at Flinders University have revealed that injury dressings found in first-aid kits can be used to identify shark species involved in bite incidents, by being used to gather DNA samples from equipment such as surfboards. This new collection method, described in the journal Forensic Science International: Genetics, can improve how shark-related incidents are investigated and provide accurate and timely information about species using regular first-aid equipment carried by surfers, boaties and emergency responders.

Dr Belinda Martin, lead author on the study, said the rapid identification of shark species is important in producing accurate information that can guide future prevention measures and reduce the number of shark incidents.

“Human–shark interactions cause public anxiety, especially following fatal bites, so identifying the species involved, although difficult, is essential to provide information to victims and communities,” Martin said.

“Eye-witness accounts aren’t always accurate, because people are dealing with trauma after the event, so we’ve tested and validated a new approach to collect DNA using regular gauze found in first-aid kits.”

The study included researchers from Flinders University, the NSW Department of Primary Industries and Queensland’s Department of Agriculture and Fisheries, and is based on three separate shark incidents in Australia and South Africa, after which samples were obtained from surf skis and a surfboard. It showed that a similar approach to PCR testing, using medical gauze to collect organic tissue and DNA samples from shark bites, works very effectively.

The researchers successfully identified the shark species responsible for each bite across all three incidents, including an example that was over a month after the incident. The researchers also tested the effectiveness of ordinary gauze when compared to specialised forensic swabs — normally used to collect genetic material from shark bite materials — and found that both the gauze and swabs worked well to identify the shark species.

“This approach is important in providing a new DNA collection technique and will be of interest to first responders, including surfers, lifesavers, police and paramedics, as well as the wider community,” Martin said.

Co-author Dr Michael Doane added that the testing method can provide samples hours to days after a shark bite that can be used to reliably identify the species.

“We have shown that the use of gauzes, which is widely available and accessible, is a simple and effective alternative to forensic-grade sterile swabs,” he said. “Therefore, we encourage the use of gauze as a means for collecting DNA by first responders, including surf lifesavers, police and first aiders.

“Moving forward, we recommend that first responders take samples for genetic analysis using sterile gauze from the bite site as soon as reasonable to limit contamination or DNA loss and increase the probability of the species being identified.”

Image credit: iStock.com/Philip Thurston