The protection afforded to blue whales in New Zealand waters may need to be increased, now a study has found they may be more regular visitors to the South Taranaki Bight than previously thought.
The whales had been thought to pass through the Bight while migrating to and from summer feeding grounds in Antarctica.
But a study by the National Institute for Water and Atmospheric Research (NIWA) of whale sightings between 1979 and 1999, and two surveys in 2011, show the whales are a regular presence.
NIWA marine ecologist Dr Leigh Torres said the study linked the presence of the whales to the large amounts of plankton - perfect whale food - in the South Taranaki Bight.
"Conventional wisdom has been that blue whales only transit through New Zealand waters while migrating," Dr Torres said.
"But this new information suggests that this is not an accurate understanding of their ecology. Blue whales appear to be present in the South Taranaki Bight with some regularity and density, and based on their foraging patterns and the availability of their prey in the area, we think they are feediing