Some marine species appear once and disappear for decades. Among them is the Sailback Houndshark, a rare shark with an unusually tall dorsal fin. It was first described in 1973 after a pregnant female was caught near the Gogol River in Astrolabe Bay (Papua New Guinea). For fifty years, this specimen remained the only record.
Return to the discovery site: Photos document a surviving population
In March 2020, researchers, together with local fishermen, found new evidence: Several photographs showed sharks with a distinctly tall dorsal fin – five females, clearly identifiable as the long-lost Sailback Houndshark. Two years later, a male was documented in the same region for the first time. This confirms that the species still exists and persists in the waters of Papua New Guinea to this day.
Bycatch instead of target species – and little value on the market
Fishermen in Astrolabe Bay report that the species is occasionally caught as bycatch, particularly when targeting “Jewfish” for the lucrative fish maw trade. Most catches occur between March and July and again during the dry season from August to November. The meat has little local value, and the fins are considered low-quality for the fin trade.
Extremely small distribution range
All recent records come from near the mouth of the Gogol River. The shark apparently prefers deeper areas on the narrow continental shelf – and comes into contact with small-scale fishermen there. The high concentration of findings in Astrolabe Bay suggests microendemism, meaning a very limited occurrence.
Some researchers suspect that the species was once more widely distributed – perhaps beyond Papua New Guinea into Indonesia. Today, only “a last small remnant population” may remain, says shark researcher David Ebert.
Threats: Overfishing and habitat pressure
As with many sharks and rays, overfishing and habitat loss are among the greatest risks. Even without targeted fishing, regular bycatch can quickly endanger a species with a small population – especially if its range is so narrowly limited.
Scientific value and next steps
The Sailback Houndshark represents an independent evolutionary lineage within the houndsharks and is therefore of high scientific interest. Two preserved specimens are held at the University of Papua New Guinea; together with partners in Australia and Florida, DNA analyses aim to establish a genetic basis for future monitoring.
“This work establishes a genetic baseline and helps develop conservation strategies,” says Jack Sagumai, lead author of the study.
Symbol for protection and cooperation
The rediscovery after half a century offers hope – and serves as a warning. Such a rare, locally restricted species can disappear unnoticed. Science, conservation measures, and the knowledge of local communities must work together to turn a curious rediscovery into lasting protection. The study has been published in the Journal of Fish Biology.
