📝 usncan Note: Rare Shark Found Again After Half A Century Near Papua New Guinea
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One of the adult female sailback houndsharks captured.
Jack Sagumai et al. (2025)
How often do we discover a new animal on our planet, only for it to disappear from sight for decades and then suddenly reemerge, reminding us it never went extinct at all? That is the story of the sailback houndshark (Gogolia filewoodi), a species described in 1973 from a single specimen collected off northern Papua New Guinea. That individual, a pregnant female caught in 1970 near the mouth of the Gogol River in Astrolabe Bay, became the sole basis for what scientists knew about the species. For nearly half a century, this shark existed as little more than a footnote in ichthyology. With each passing year, no other confirmed sightings were recorded, despite targeted shark and ray studies and deep-sea surveys across the region, fueling speculation that it had slipped quietly into extinction before we even had a chance to study it properly.
Scientists knew very little about the sailback houndshark before it vanished. While it belongs to the houndsharks (a family that includes more familiar species such as smoothhounds and weasel shark), it is the only member of its genus, meaning it represents a unique evolutionary lineage found nowhere else on Earth! Its most recognizable feature is its unusually long first dorsal fin, a trait that gave rise to the “sailback” name. Beyond that? Information on its biology, behavior, and population size is virtually nonexistent.
And it seemed it would remain that way. Then, in 2020, the shark made a surprising return with the first reliable records of the shark since its original discovery.
Between February and May 2020, a World Wildlife Fund facilitator working in Bilbil village recorded the capture of the five sailback houndsharks near the Gogol River mouth. Two were caught at a depth of about 260 feet (80 meters), while three more were caught the next day. All were females, one of which carried five well-developed eggs in her ovary. In 2022, the 28.7 inch (73 centimeter) male was caught nearby at a depth of roughly 660 feet (200 meters), the first time scientists had ever confirmed a male of the species. After almost 50 years without a trace, scientists now had proof that the sailback houndshark was still alive in the very same waters where it had first been discovered! Surprisingly, local fishers described the species as an occasional bycatch when targeting fish part of the Sciaenidae family to the authors of a new study highlighting this find, led by Jack Sagumai of WWF Pacific. Valued for their swim bladders, or fish maw, fish in the Sciaenidae family fetch high prices in international markets. The sharks are another story — their flesh is not well regarded and is often given away, while its fins are considered poor quality for the global shark fin trade. While this may sound like a stroke of luck for the species, the rising demand for fish maw means fishing pressure is increasing in the very waters it seems to call home.
It only being found in this area is another reason why scientists are paying close attention. Despite years of biodiversity surveys across Papua New Guinea, this shark has only ever been recorded in Astrolabe Bay near the Gogol River mouth. If its range truly is that small — which is scientifically known as micro-endemism — then the species could be particularly vulnerable to overfishing. With little room to escape, even the most modest of increases in fishing effort could have devastating impacts on its population. And we don’t even know how many there are to begin with… in fact, we still don’t know how long the species lives, how many pups females produce, or how often they reproduce. Nor do we know whether its range extends beyond Astrolabe Bay or whether it is truly restricted to this small stretch of northern Papua New Guinea. Each of these unknowns makes it difficult to design effective management plans. For now, the sailback houndshark remains listed as “data deficient” on the International Union for Conservation of Nature Red List, meaning researchers simply don’t have enough information to judge its conservation status. But rare and endemic species with restricted ranges are often among the first to be pushed toward extinction when human activity ramps up, meaning the fate of the sailback houndshark is of great concern. The discovery of six individuals in a relatively short time frame suggests the shark may be more common than previously thought, at least in this corner of Astrolabe Bay, but without proper monitoring it’s impossible to know whether the species is stable, declining, or already in trouble.
What might offer a glimmer of hope for these sharks are the very communities that sometimes catch them. On one hand, while local fishers are part of the pressure facing the sailback houndshark, their knowledge was also the reason for its rediscovery. It wasn’t advanced deep-sea equipment or major research expeditions that brought this species back into the scientific record but observations and reporting from fishers and community facilitators. That kind of firsthand knowledge is invaluable. These fishers know where and when certain species appear, which waters are most productive, and which animals turn up only occasionally. Partnering with them could reveal critical hotspots for the sailback houndshark, giving scientists the data they need to design effective conservation strategies. In places where formal surveys are rare and resources are limited, local ecological knowledge may be the only way to build a foundation for protecting species like this one.
