Taking a deep dive into our Fiordland marine reserves

Department of Conservation —  13/05/2021 — 1 Comment

“Ultimately, Fiordland is one of the most unique environments in the whole country and just a really special, special place,” says Richard Kinsey, the senior Biodiversity Ranger for the Fiordland Marine Area.

In February, DOC Te Anau organised a trip aboard the Fiordland based DOC vessel Southern Winds and put out a scholarship for emerging scientists to join him on board. The resulting four research projects each examine something unique to Fiordland and help us understand the ecosystems within some of our most remote mainland marine reserves.

The steep walls of the fiords are one factor which makes the marine reserves around here so unique.
📷: Mon Ladds/DOC.

There are ten marine reserves in the fiords. Most were established in 2005, a process which formalised the Fiordland (Te Moana o Atawhenua) Marine area and the Fiordland Marine Guardians. Two reserves –Piopiotahi/Milford Sound and Te Awaatu Channel (“The Gut”) in Pātea/Doubtful Sound– were established in 1993 after being proposed by the commercial fishing industry, who saw the potential to protect the diverse and fragile fiord ecosystem.  

“The whole ethos of the Fiordland management process worked on gifts and gains, so giving something back, taking something,” says Kinsey.

This is the first time that DOC has run a research trip in this way.  

“We got to a stage with the Guardians and with DOC where we are able to create some opportunities for people to get enthused about working in the fiords and to come back again in the future.”

The first fur seal count in fifty years

The last time NZ fur seal pups were ground counted on this coasts, New Zealand was still protesting the Vietnam War and the steam-hauled train between Dunedin and Christchurch was about to make its final trip.

Fur seal colonies have been known in Fiordland for centuries. Captain Cook’s crew recorded killing fur seals in Dusky Sound in 1773.  In the following 60 years, tens of thousands of skins were taken from the area. Despite these early records, there have been almost no counts undertaken on these colonies since.

In general, New Zealand fur seals populations are expanding and rebounding, particularly in the North Island. However, the west coast of the South Island has had declines in previous decades. 

This fur seal colony could be the setting for a Disney movie.
📷: Mon Ladds/DOC.

This trip surveyed Doubtful Sound/Pateā, Dusky Sound, Breaksea Sound and Chalky Inlet and estimated that between 14 and 24 thousand seals make their home in lower Fiordland. “The pup counts and population estimate indicate the fur seal numbers are substantially higher than previous records, a good sign of a healthy ecosystem for a top marine predator like the NZ fur seal.” says Lousie Chilvers of Massey University.

Sea-urchin for healthy kina

Kina are a good indicator of a thriving ecosystem, when their numbers are in balance with other species. However, when their population get too high, over-grazing of kelp causes large ‘kina barrens’ – an ecosystem change which affects many other species.

“I’m looking at the health and density of kina and kina barrens,” says Kelsey Miller, PhD student at the University of Auckland.

She’s mapping kina populations and looking at how marine reserves affect their health. Interestingly, many have been found with their guts full of flatworms, a parasite that loves to live inside kina.  Kelsey is looking at whether parasites affect the health of kina and whether they are healthier in areas that have plenty of kelp species to eat.  

A large kina, the endemic New Zealand sea urchin.
📷: Mon Ladds/DOC.

“There were an average of 160 flatworms in each of the kina we sampled,” she says (these were collected from outside the marine reserves!). “This flatworm is already found in high densities in kina in the Hauraki Gulf, so it’s interesting to find them in Fiordland. There is some evidence that rising sea temperatures might help this parasite spread and infect new hosts.”

What does it take to become a parasite?

Dr Maren Preuss (Victoria University in Wellington, supported by the Marsden Fund) studies parasitic red algae. Maren is interested in understanding the changes that occur when an organism switches from a free-living to a parasitic lifestyle.

“Basically,” she says, “an algal spore evolved into a parasite after settling on its parent and parasitizing it. Incredibly, this transition has happened not only once but over 100 times in various red algal species.”

The parasitic algae, indicated by the white arrows, living on the host algae.
📷: Maren Preuss.

New Zealand has an incredible and unique algal/seaweed diversity, with many species yet to be properly named and studied.

“At least one new alga is discovered on nearly every research trip we do,” says Maren. The DOC voyage led to the collection of 1 known and 7 completely new parasitic red algal species. These samples will further our understanding of how parasitism evolved.

“I want to show people that seaweed can be interesting!” she says. “There are a lot of undescribed species, and so much interesting research that needs to be done in New Zealand”. 

Plenty of fish in the sea

Baited remote underwater video (BRUV) is a versatile way to estimate the number of fishes in an area. It’s a simple concept: attach a camera to a metal frame, strap on a canister filled with bait, and see who comes for a nibble, much like morning tea leftovers on a lunch table.

“We’re using BRUVs to survey the fishes inside and outside the marine reserves in Fiordland,” says Odette Howarth from Massey University, “Do we see a difference between the two?”

Scarlet curious banded wrasse checks out the camera while blue cod and more banded wrasse focus on the bait box behind.
📷: DOC.

BRUV units were deployed between depths of 10-100m across a variety of habitats (silt, mud, rocky reef, cobble, sand) both inside and outside marine reserves. 90 sites were sampled, meaning more than 90 hours of video was collected for analysis an ongoing task.

“We have recorded 17 fish species so far; out of these 6 were sharks or skates. We also recorded some invertebrate species, predominantly sea pens and brittle stars. We only recorded one crayfish at one site, although it was quite large, at least 4kg.”

A sea pen (right). Sea pens are cnidarians, a group of species which includes corals, anemones, and jellyfish.
📷: DOC.

Marine reserves are often the best places to conduct research like this, as they set a ‘baseline’ to study the rest of the ocean.

We’re ramping up our monitoring at marine reserves all over the country. Expect more amazing footage like this as our dedicated rangers and scientists keep their eyes trained on our big blue backyard.


Learn more:

Fiordland Marine Reserves

One response to Taking a deep dive into our Fiordland marine reserves

  1. 

    What a cool initiative!

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