Recent sightings of whales, as well as Hector's and Dusky dolphins, off the coast of Kaikoura have brought immense relief to locals and tour operators.

Forest and Bird marine advocate Anton van Helden was optimistic about the welfare of Kaikoura's many deep-diving species - among them sperm whales, humpback whales, Southern right whales, orca and several dolphin species.

While the submarine Kaikoura Canyon provided a productive ecosystem for whales and dolphins, there were similarly productive habitats elsewhere that could have served as alternatives.

But he expected that, even with considerable uplift around the canyon area - and the potential of landslides - the systems would have been easily large enough to sustain the quake's effects.

"The other thing, with sperm whales, it is only males that would effectively be there at the moment, so this is the time of year when there would be fewer of them in the region."

However, early indications showed Kaikoura's resident fur seals would have fared worse.

At Ohau Point, a large slip had caused heavy damage to a specially protected seal sanctuary, and it was likely some animals would have perished.

"It's too soon to be able to know the full impact that the earthquake will have had on the local population," Department of Conservation science adviser Laura Boren said.