by Gwynn Guilford
Conservation biologist Joshua Drew studied antique shark-tooth weapons to explore shark biodiversity in the waters around Kiribati. Ed Yong relays what Drew discovered:
Drew found that the teeth in the weapons came from 19 species of shark, and that three of these — the spottail shark (Carcharhinus sorrah), dusky shark (Carcharhinus obscurus) and bignose shark (Carcharhinus altimus) — are no longer found in waters close to the islands. The spottail and dusky sharks were among the four species most commonly used to make the weapons, but records suggest that they are no longer found within a few thousand kilometres of the Gilbert Islands.
In line with a common theme of late, shark-finning may be responsible:
It is not clear why the species vanished but Drew says it is “absolutely possible that humans had a role in these declines”. Shark-finning — the practice of hunting sharks for their fins alone, which kills sharks in much greater bulk than ordinary fishing — was first recorded in the area in 1910. However, by that time the practice was probably already well established.