Rising temperatures to make areas in New Zealand unsuitable for whales

A new study has shown many areas around New Zealand would become unsuitable for blue and sperm whales as global sea-surface temperatures continue to rise.

With the new modelling predicting they would be seeking refuge further south.

Areas around New Zealand’s southern and eastern offshore islands would likely become more suitable for these species, but the move would have a destabilising effect on marine ecosystems.

These changes would likely have a negative effect on tourism in areas such as New Zealand’s Kaikoura, known for whale watching, as sightings became less frequent and less reliable.

This is according to the study recently published in the international journal Ecological Indicators,

Most of the tourists going on a whale watching tour in Kaikoura could spot whales from their boats, Nick Jiang, a tour operator in New Zealand’s South Island, told Xinhua on Thursday.

However, the chance of spotting a giant sperm whale was decreasing.

Instead, killer whales, humpback whales and other smaller whales were much easier to be spotted, Jiang said.

Selling boat tickets for whale watching in Kaikoura, TripAdvisor said on its website.

“You are almost guaranteed to spot a whale, as you’ll receive most of your ticket price back if you don’t.’’

Most of the whale watchers’ comments on TripAdvisor were positive, such as well worth the money and a once-in-a-lifetime experience.

The international collaborative study between Massey University, Universities of Zurich, Canterbury, and Flinders, has shed light on how climate change would impact the distribution of great whales in New Zealand waters.

It used a complex modelling approach to project the regional range shift of blue and sperm whales by the year 2100, under different climate change scenarios.

The study showed a southerly shift of suitable habitat for both species, which “increases in magnitude as the ocean warms.’’

The most severe climate change scenario that was tested generated a 61 per cent loss and 42 per cent decrease in currently suitable habitats for sperm and blue whales, mostly in New Zealand’s northern waters.

“Regardless of which of the climate change scenarios will be the reality, even the best-case scenario indicates notable changes in the distribution of suitable habitat for sperm and blue whales in New Zealand.’’

Dr Katharina Peters of the University of Canterbury, who led the research had said.

Peters said that Island nations such as New Zealand were extremely vulnerable to climate change’s impact on marine ecosystems because of their strong connection to the ocean.

He added sperm whales in New Zealand were critical for the tourism industry and local economy.

Great whales, such as sperm and blue whales, were important ecosystem engineers.

This meant that they fulfilled a multitude of tasks such as facilitating the transfer of nutrients from deep waters to the surface and across latitudes via migration from feeding to calving areas.

Their predicted future southward shift, driven by climate change, would impact ecosystem functioning and potentially destabilise ecological processes in the northern part of New Zealand, the study showed.

The study also highlighted habitats that might be suitable in the future for both whale species in New Zealand’s South Island and offshore islands, which provided an opportunity for their increased protection in the future.

(Xinhua)