Blue whales off New Zealand are a distinct population

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Blue whales off New Zealand are a distinct population

May 17, 2018 - 19:12
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Study shows New Zealand has its own population of blue whales which are genetically distinct from other blue whales in the Pacific Ocean.

A new population of at least 700 blue whales has been found living between the North and South Islands of New Zealand. While they are not as large as their Antarctic cousins, the New Zealand population can still reach lengths of around 22 metres.

The study, led by Oregon State University's Marine Mammal Institute, found that the group of whales show a high level of residency and are also genetically distinct from whales found in the neighbouring Pacific and Antarctic Oceans, suggesting they are a separate group that lives permanently in the region.

Resident blue whales

Though blue whales have long been listed as a migrant species in the region, Dr Leigh Torres of the Marine Mammal Institute at Oregon State University was the first to suggest it might be home to a resident population. Torres and her graduate student, Dawn Barlow, led longer surveys in the summers of 2016 and 2017, trying to determine the abundance, distribution patterns and population structure of the New Zealand blue whales. They used biopsy darts to determine the genetics of the whales, compared sightings with photo IDs of whales from other regions, and listened to the hydrophones deployed in the region for two years.

Having established this new population, the scientists now want to determine exactly how many of them there are inhabiting the large bay of South Taranaki Bight. Their current minimum estimate is 718.

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