Green Sawfish Are on the Brink of Extinction, But Scientists Don’t Know How Many Are Left

**Green Sawfish at the Brink of Extinction: Urgency for Conservation in Australia**

A new review of research indicates that the green sawfish, a critically endangered species, may be facing an uncertain future. The study, published in the journal *Reviews in Fish Biology and Fisheries*, highlights significant gaps in knowledge regarding the population sizes and habitat locations crucial for the survival of these unique creatures.

The research team, led by Jack Ingelbrecht and David Morgan from Murdoch University’s Centre for Sustainable Aquatic Ecosystems, examined 123 peer-reviewed studies conducted since 2005. They found that about 80% of the global population of green sawfish resides in Australian waters, where fishing remains the predominant threat to their survival.

Despite the alarming status of the species, scientists discovered minimal concrete data on essential aspects needed for effective conservation efforts. Ingelbrecht lamented the lack of vital information, stating, “When it comes to the research areas most relevant to conservation—the size of remaining populations, the locations of critical habitat, and the number of mature individuals present in the wild—there’s very little information currently available.”

The green sawfish, also known as the longcomb sawfish, can grow beyond 19 feet in length, with the largest individuals potentially reaching 24 feet. Their distinctive flattened snouts, equipped with 23 to 37 teeth on each side, are employed to hunt for prey; however, these same features contribute to their vulnerability, as they can easily become entangled in fishing nets.

Once inhabiting waters across at least 37 countries, ranging from the Mediterranean Sea to Eastern Australia, the range of the green sawfish has now diminished to just 14 nations. Over the last 50 years, the population is suspected to have decreased by more than 80%, primarily due to fishing activities and the loss of coastal habitats. Current estimates suggest there may be fewer than 10,000 adult sawfish remaining, but the reliability of this figure is under scrutiny.

While much of the species’ historical range has been lost—including areas in Africa and southern Asia—northern Australia still harbours some of the last intact populations. The Ashburton River and its adjacent tidal creeks in Western Australia’s Pilbara region are noteworthy as both a birthing site and nursery for the green sawfish. Over the past 15 years, genetic studies have confirmed that at least 50 females have given birth in this area, with at least 10 returning for subsequent births.

Morgan, who has conducted sawfish research in Australia for over two decades, noted the significance of this finding: “It gives us a rare opportunity to understand how green sawfish use their environment, and identify which conservation measures would best facilitate their recovery.”

Tracking adult green sawfish poses a challenge due to their offshore habitat and depths of up to 130 metres. In Australia, the situation remains critical, as fishing threatens their survival, with fewer than 17% of reported individuals being found within protected areas.

Ingelbrecht remains optimistic about the potential for change. “There’s still a genuine opportunity to turn things around,” he asserted. “With the right support, the right research, and the right conservation measures, we can ensure the survival of green sawfish. I hope Australia sets an example the rest of the world can follow.”

The pressing need for targeted conservation efforts is underscored by the fact that this species is emblematic of larger issues facing marine biodiversity. As awareness grows about the plight of the green sawfish, conservationists and researchers must continue to advocate for policy changes and protective measures to secure the future of this remarkable species. Without immediate intervention, the green sawfish may swim into the annals of history as yet another example of the fragility of our planet’s aquatic ecosystems.