A new study has found the Kaikōura earthquake affected sperm whales' ability to find food for at least a year.

Led by the University of Otago, marine sciences teaching fellow Dr Marta Guerra said research groups had already been monitoring sperm whales since 1990.

"We had the advantage of all of that previous data, so when the earthquake struck we knew where they [sperm whales] were usually feeding and what was their usual behaviour," Guerra said.

The Kaikōura 7.8-magnitude earthquake on November 14, 2016 produced strong ground shaking which triggered widespread mudslides in the underwater canyon off the coastline, the study explained.

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Scientists had been examining the behaviour of 54 sperm whales between January 2014 and January 2018.

They found whales spent about 25 per cent more time at the surface after the earthquake.

Marine Mammal A new study has found sperm whales in Kaikōura had their food source disrupted for up to a year following the 2016 7.8-magnitude earthquake.

"With sperm whales, because they feed at depths and spend so much time underwater, it's hard to know exactly what is going on but you can use these times at the surface to determine what they are doing," Guerra said.

"Time at the surface is recovery time, so it's crucial for exchanging air and making sure they oxygenate,

"Spending more time on the surface means they're probably spending more effort while they're diving and searching for food, that makes them spend longer at the surface recovering."

There are two main reasons the whales may have expanded their search effort, the study explained.

This was due to potentially sparser prey or whales having to "re-familiarise" with a modified habitat.

Marine Mammal Dr Marta Guerra tracking sperm whales in Kaikōura.

The study also found large underwater sounds produced by earthquakes and aftershocks "induced injuries, hearing damage, displacement and behavioural modifications".

"The whales depend on sound for communication, detection of prey and navigation and are also highly sensitive to noise."

Guerra said that while earthquakes and other extreme natural events were rare, they could shift the state of ecosystems by wiping out animals and plants.

"Understanding how wild populations respond to earthquakes helps us figure out their level of resilience, and whether we need to adjust management of these populations while they are more vulnerable," she said.

Marine Mammal Otago University researchers at Kaikōura prepare to track sperm whales behaviour.

She said scientists were particularly surprised how clear the changes were, especially in terms of where the sperm whales were feeding.

"The head of the Kaikōura canyon, where we use to frequently find sperm whales foraging, was quiet as a desert.

"Just why the canyon is important to sperm whales is a piece of the puzzle we are still trying to nut out, but it's likely related to the immense productivity of the canyon's seabed, and a combination of how the currents interact with the steep topography of the submarine canyon."

They found the whales' behavioural changes lasted about a year after the 2016 earthquake and returned to normal levels in the summer of 2017-18.

Findings from the study has been published in Deep Sea Research Part I, which Guerra was lead author.

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