Researchers from Oregon State University (OSU) have discovered that a population of blue whales found between the North and South islands of New Zealand are genetically distinct from other blue whales, and live there year-round.
(From Forbes/ By Fiona McMillan) — The first inklings that something unusual was going on began back in 2011, when seismic researchers were surveying the South Taranaki Bight, between the North and South islands. The researchers had observed 9 blue whales in the area, and reported this cluster of sightings to their colleague Leigh Torres, a principal investigator at the OSU Marine Mammal Institute.
Intrigued, Torres examined whaling records from the area and, indeed, it seemed the South Taranaki Bight was a particularly active area for blue whales. Analysis of oceanographic patterns and documentation revealed that this stretch of water has an abundance of particular species of krill that blue whales like to dine on, which might explain its popularity with the whales.
Torres and colleagues subsequently made the journey to the South Taranaki Bight themselves, and over the course of just 10 days, identified 50 individual blue whales.
According to the New Zealand Threat Classification System, which monitors species according to their threat of extinction, the blue whale is listed as a migrant. But the persistence of a steady food supply for blue whales in the South Taranaki Bight and the regular sightings of the whales themselves had Torres wondering if these particular whales had a more permanent presence.
Torres and graduate student Dawn Barlow embarked on more surveys in 2016 and 2017 to get a better picture of just how many blue whales were frequenting the Bight and how they were distributed. Using photographic comparisons and other data, they were able to identify 151 individual whales in the area.