Understanding the future of New Zealand’s unique Fiordland marine ecosystem

Returning from a 7-day voyage to Doubtful Sound, researchers from Victoria University of Wellington have been gathering information that will help them to predict how global climate change might impact New Zealand’s Fiordland ecosystems.

“After the success of the University’s voyage last year, and with funding support from the Department of Conservation, we were eager to get back on board the research vessel Southern Winds and continue our study with The Department of Conservation team,” said Dr Alice Rogers, who joined the Fiordland research team for the first time this year after being appointed as a lecturer in fisheries science at the beginning of 2018.

Like many locations worldwide, New Zealand is set to experience as much as a 2 degree increase in water temperatures over the next 50 years. This could have significant consequences for marine organisms, and for the valuable services they support, such as fisheries and tourism, says Dr Rogers.

“Last year we focussed on finding out about the distribution and abundance of organisms in the fiords, but this time it was all about understanding how the ecosystem works,” says Professor James Bell, who led the team’s first research cruise to Fiordland in 2018. “Warming waters will affect some organisms more than others, but even small changes can cascade through communities with unexpected consequences. Knowing how everything is connected is vital if we are to determine the best management practices to protect this unique environment for future generations.”

Exploring locations from the inner (landward), to outer (seaward) fiords, the research team conducted underwater SCUBA surveys, deep dives with a remotely operated vehicle, and collected water samples and specimens from the shallows to the deep.

“With the information we’ve gathered we will be able to answer a lot of questions. We will be able to say what the main sources of food are in different parts of the fiords, who eats who, and which organisms are most important to the overall health and stability of the ecosystem,” says Dr Rogers.

The research team, including five PhD students, is now back at Victoria University of Wellington to process and analyse their data. So far, they are noticing striking differences between communities based on their position within the fiords, Dr Rogers says.

“Sites closer to the land tend to have simpler communities, whereas those closer to the ocean are much more diverse,” she says. “Having said that, some species seem to be able to do equally well in all locations, and these may represent those that will be most resilient to future environmental change.”

The team produced the following video to document their trip. The video includes footage from shallow reef surveys, a fishing trip to sample common fish species, and on-board activities including water filtering and sample preparation.