First Documented Resighting of a Dwarf Minke Whale From Calf to Adulthood in the Great Barrier Reef Indicates Long-Term Colour Pattern Stability and Site Fidelity.

Dwarf minke whales occur throughout the Southern Hemisphere but the only predictable winter aggregation area is in the northern Great Barrier Reef (GBR). Interannual site fidelity has been recorded frequently there for > 20 years in males and breeding females; mothers with calves are seen occasionally, but a calf has never been recorded as returning after its birth year. Every photographed calf between 2003 and 2023 was compared with a catalogue of known GBR individuals and MW0088 'Rudi,' first seen as a calf in 2006, was found to have been resighted intermittently to 2017-when presumably a mature 11-year-old. This is the first direct evidence for natal wintering ground fidelity in GBR dwarf minke whales and provides one of the longest sighting histories in the GBR and globally. Detailed analysis of MW0088's colour patterns showed almost no variation over the 12-year period, confirming their value for individual photo-identification over extended periods. The likely repeated long-distance migrations of MW0088 to the same GBR location support the designation of this aggregation area as biologically important for this population of a still undescribed minke whale subspecies.