Aotearoa New Zealand is a hotspot for marine diversity.
Due to its wide variety of coastal environments and habitats, Aotearoa New Zealand is a hotspot for marine diversity. This interactive, featuring infographics from the Department of Conservation, explains how and why our marine areas are so diverse.
To use this interactive, move your mouse or finger over any of the labelled boxes and click to obtain more information.
Background image: Dr Leigh Tait/NIWA
Transcript
Marine diversity hotspot
In New Zealand’s waters, 51% of reported species are endemic, meaning they are only found here. There are over 6,000 known species of endemic invertebrates and hundreds of endemic seaweeds and fish species. In a 2008 international study of known marine biodiversity, New Zealand ranked the highest in the world for the proportion of endemic species, with Antarctica in a close second at 45% and Australia third at 28%. This should not come as a surprise considering the geographic isolation of Australia and New Zealand, which separated from other land masses about 83 million years ago.
We have about 1,400 species of fish, nearly 300 of which are endemic, over 1,000 species of seaweeds, 1,100 species of jellyfish, anemones and rocky corals, 1,500 species of sponges, 600 species of sea stars and other spiny creatures, 3,600 species of mollusc and 2,600 species of crustaceans such as rock lobster.
The high number of species of sponges is exceptional, including the exciting carnivorous sponges that were discovered in 1995. Around half of the world’s cetaceans, which includes dolphins and whales, have been recorded in our exclusive economic zone. A few of these are endemic, including the critically endangered Hector’s dolphin.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
Diverse coastal environments
New Zealand’s coastal environment is quite diverse. There is a 6°C difference in water temperature from subtropical Northland to the subantarctic Auckland Islands in the south. A temperate ‘ribbon’ of water runs below southern Australia and around a great portion of our two mainland islands. Different ocean currents run around the globe, bringing with them warm tropical waters, cold deep-ocean waters and nutrients. The mixing of these different currents creates unique zones that support an incredible diversity of life.
Perhaps one of the most remarkable things about features of New Zealand’s waters is its diversity of habitats. There are a multitude of habitat types identified in the coastal regions alone. At Poor Knights Island, you can dive in warm, subtropical waters with sea turtles – a short flight later, you can see elephant seals in Fiordland.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
New Zealand’s EEZ
New Zealand is considered a world hotspot for biodiversity. This is easy to see on land, with our many iconic species like kiwi, tuatara and wētā. The marine environment is no different! The significance of the ocean to our lives is perfectly summed up in the name of our region of the world – Oceania.
Oceania, in the southeast Asia-Pacific, includes Australasia, Micronesia and Polynesia. These Pacific islands are generally located in warm, tropical waters and have recognisable features such as bright coral reefs. New Zealand, situated further south, has different environmental factors that influence the species found in our marine waters. At 4.2 million km² (about 15 times the size of our land mass), our exclusive economic zone (EEZ) is the fifth largest in the world. Our EEZ has about the same known species diversity as the entire European region EEZ, which is about 5.5 times larger.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
Our EEZ is deep
New Zealand’s marine environment includes the exclusive economic zone (EEZ), which extends 200 nautical miles from our coastline and the wider continental shelf of Zealandia. Three out of four of the deepest ocean trenches in the world are found in Oceania. The Kermadec Trench, in our EEZ, is the second deepest ocean trench in the world. At 10,047 m, it is significantly deeper than Mount Everest is tall.
Other underwater features such as seamounts, hills, knolls, guyots, methane seeps, volcanoes, hydrothermal vents and canyons all provide areas for life to thrive.
Seamounts are underwater mountains. There are over 800 known seamounts in our EEZ, most of them found deeper than 1,000 m. These are often areas of high biodiversity, but not many have been researched.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
Deepwater discoveries
Globally, it is estimated that between 25% and 80% of marine species are yet to be described. In New Zealand, it is generally considered that up to 85% of our biodiversity could be in the ocean. Many of these species are still undiscovered, including at least 760 species of undiscovered fish.
The deep ocean in particular (deeper than 2,000 m and over 10 km deep in places) is expensive and time-consuming to explore, so many of its inhabitants and habitats are yet to be discovered.
The deep sea is a hostile environment, which supports an astounding amount of life. Creatures here must adapt to survive under very high pressure in complete darkness. Deeper than 1,000 m, the only source of light comes from bioluminescence – light produced by living creatures. Most of the food and nutrients here arrive by falling from the water column above, although some organisms can get their energy from deepsea vents and seeps.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
Coastal discoveries
Most of what we know about our marine environment is in shallow coastal waters, which are easier to access and research. Despite this, we are making new discoveries all the time from shallow to deep waters. We are still discovering new species of all sizes, such as a new species of deepwater giant sunfish (Mola tecta) discovered in 2017 and the shallow-water Trnskii’s clingfish (Dellichthys trnskii) found in 2018. New habitats have also been discovered and researched, such as the deep rocky reefs located between 50 m and 300 m deep.
Download the Department of Conservation infographic as a PDF.
Copyright: Department of Conservation
Acknowledgment
This resource is another great collaboration between the Department of Conservation and the SLH. Infographics and text are supplied by DOC.
