Imax

2008. Howard and Michele Hall are at the Neptune Islands filming Under the Sea 3D for IMAX theatres.³⁴ A subadult male, at least 3.5 metres, shows up with a bent tail — caudal fin deformed, unmistakable. They name him after the format. He gets catalogued. He leaves.

He comes back. 2009. 2010. 2011. Every winter, the same broken tail in the same water. By the time the streak reaches ten years, it is already the longest unbroken residency in the Foundation's records.² It kept going. Sixteen consecutive calendar years, 14.5 years of confirmed presence — no other white shark in a database of over two thousand has come close.⁴

The tail makes him easy. You can confirm Imax from a single frame, in bad visibility, at distance.⁴⁵ No need to compare pigmentation or dorsal fin profiles. That bent caudal is his signature, and it has made him the most reliably identifiable white shark at the Neptune Islands.

He used to be a winter shark. In recent years he has started turning up in summer too.⁴ Nobody knows why. But nobody would have noticed the shift without sixteen years of data behind it.

He is probably over thirty now.⁴

Deformed caudal fin — bent, permanent, visible at distance and in low visibility. Sufficient for single-frame identification. Dorsal fin and pigmentation provide secondary confirmation. 3.5m+ at first recording (2008); likely well over 4m now.

Originally a winter visitor. Now also recorded in summer months.⁴ No explanation for the shift. No other unusual behaviours publicly reported.