A southern right whale's visit to Wellington Harbour may be a sign the population is recovering following the decimating impacts of commercial and illegal whaling in the last two centuries, an Auckland marine scientist says.
The whale has been in Wellington Harbour for the past week delighting locals with its regular breaching close to shore.
University of Auckland marine science PhD student Victoria Warren has been involved in analysing some of the data recorded in Wellington Harbour by NIWA scientists last week.
She says southern right whales undertake annual migrations, swimming north from Antarctica.
A breeding population is known to congregate around the Auckland Islands each year and the whales have also been recorded around the New Zealand mainland in increasing numbers.
"It may be a sign of a recovering population following the decimating impacts of commercial and illegal whaling during the 19th and 20th centuries," Ms Warren said.
A skin biopsy of the whale was also obtained last week in a collaboration between NIWA and the Department of Conservation.
The huge marine mammal has been in the harbour for a few days, and today it was especially active.
However, results - which will be able to determine its sex - are not expected for some time and will be undertaken by the University of Auckland.
Speculation last week that it is male due to its activity near the surface and regular breaching, possibly to attract females, is premature, Ms Warren said.
"Male whales may undertake these activities to attract females or intimidate other males, but there is no need for a southern right whale to do this. Female southern right whales mate with multiple males, and the male that produces the most sperm is usually the one that fertilises the egg," she said.
On the breeding grounds, southern rights are generally active at the water's surface as they prefer water depths only slightly deeper than their own body depth. Ms Warren says the aerial activities of the whale in Wellington Harbour should not be cause for concern.
Commuters were given a rare treat this morning as the large mammal fed on a school of fish.
NIWA also deployed acoustic equipment in the harbour to record any sounds made by the whale which could indicate its gender.
Southern right whales are a vocal species, but a gunshot sound they make is primarily produced by males, with the gunshot sounds produce by females less common and quieter than those of males.
Seventy minutes of acoustic data were recorded by NIWA between noon and 3pm last Wednesday during which the animal was within about 100m of the boat.
"No gunshot sounds were recorded, so we have no more clues about the animal’s gender," Ms Warren said.
The whale was seen near Miramar yesterday and there have also been sightings reported near the Ferry Terminal today.
Ms Warren says it's impossible to tell how long the whale will remain in the harbour but the species feeds in Antarctic waters over summer and will only eat opportunistically over winter.
Southern right whales migrate south between September and November.
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