Each whale has a unique pattern of callouses, allowing researchers to recognise individuals. Photo: Will Rayment : Whale numbers are coming right

A southern right whale surfaces off Victory Beach in Wickliffe Bay on the Otago Peninsula. Harbour Cone is visible in the background. Photo: Stephen Jaquiery : Whale numbers are coming right

A southern right whale photographed near Brighton. Photo: Stephen Jaquiery : Whale numbers are coming right

Southern right whales off St Clair Beach. Photo: Peter McIntosh : Whale numbers are coming right

A southern right whale ‘‘lobtails’’ in Port Ross, in the Auckland Islands. Photo: Marta Guerra : Whale numbers are coming right