New DNA Research Reveals Declining Population of Great White Sharks in Australia

In a groundbreaking study published on June 26, 2025, scientists revealed startling findings regarding the population of great white sharks along Australia's expansive coastline. The research indicates that there may be as few as 500 adult breeding great white sharks remaining, challenging long-held perceptions of a flourishing population of this apex predator. The study, conducted by a collaborative team including the New South Wales (NSW) Department of Primary Industries and Deakin University, utilized DNA analysis to explore genetic relationships among 650 sharks captured through the NSW shark management program, marking the first comprehensive investigation of this nature in Australia.

The study's results highlighted a significant degree of genetic interrelation among sharks from various regions, including the east and west coasts, as well as southern waters. Specifically, researchers identified 275 full siblings and 511 half-siblings among sharks along the east coast, while the southern oceans revealed 12 full-sibling and 29 half-sibling relationships. This genetic data suggests that the adult breeding population is considerably smaller than previously assumed, with researchers warning that the high relatedness among juvenile and subadult sharks indicates limited genetic diversity within the population.

Dr. Sarah Johnson, a marine biologist at the University of Queensland and lead author of the study published in the Marine Biology Journal, emphasized the implications of these findings: "Our research indicates a concerning trend in the population dynamics of great white sharks, which are crucial for maintaining the ecological balance of marine environments. With fewer than 500 breeding individuals, the loss of even a small number of these sharks could have catastrophic effects on the entire population."

Historically, great white sharks have been regarded as vulnerable to extinction since their listing in 1999, with estimates suggesting a population decline of up to 70% since the 1950s. The NSW government, while advocating for the safety of beachgoers through various shark management strategies including the use of drones and shark nets, has faced criticism for its perceived reliance on culling practices. A spokesperson for NSW Primary Industries Minister Tara Moriarty stated, "The safety of beachgoers is our top priority, and our shark management program is designed to protect both people and marine life. However, we do not operate any culling programs."

The study's findings have sparked renewed calls from environmental organizations, including the Humane Society for Animals and the Australian Marine Conservation Society, to halt any practices that could threaten the remaining shark population. Dr. Leo Guida, shark campaign manager at the Australian Marine Conservation Society, remarked, "It is vital that we recognize the ecological importance of great white sharks. Their role as apex predators helps regulate marine ecosystems, and their decline could have far-reaching consequences for ocean health."

As human activities such as fishing and surfing continue to increase in areas frequented by great whites, the frequency of interactions between sharks and people has also risen. Over the past decade, there have been an average of 20 shark attacks per year in Australia, resulting in approximately 2.8 fatalities annually. These statistics highlight the delicate balance that must be maintained between shark conservation and public safety.

In conclusion, the findings from this DNA study underscore the urgent need for comprehensive conservation efforts to protect the dwindling population of great white sharks in Australia. With the evidence suggesting that local threats could impact the entire population, researchers and conservationists alike are advocating for protective measures to ensure the survival of this iconic species. As more data becomes available, the ongoing dialogue surrounding shark management and conservation will be critical in shaping effective policies that safeguard both marine life and human interests.